Specialty: Internal Medicine, Allergy, Infectious Diseases
Massachusetts General Hospital
Infectious Disease Associates
55 Fruit Street GRJ-5
Boston, MA 02114
The following is a list of recent publications for which this Partners Asthma Center physician has been cited as an author in PubMed databases. Study abstracts have been provided for your convenience.
Thomas, S. Y., R. Hou, et al. (2003). "CD1d-restricted NKT cells express a chemokine receptor profile indicative of Th1-type inflammatory homing cells." J Immunol 171(5): 2571-80.
CD1d-restricted T cells (NKT cells) are innate memory cells activated by lipid Ags and play important roles in the initiation and regulation of the immune response. However, little is known about the trafficking patterns of these cells or the tissue compartment in which they exert their regulatory activity. In this study, we determined the chemokine receptor profile expressed by CD1d-restricted T cells found in the peripheral blood of healthy volunteers as well as CD1d-restricted T cell clones. CD1d-restricted T cells were identified by Abs recognizing the invariant Valpha24 TCR rearrangement or by binding to CD1d-Fc fusion tetramers loaded with alpha-GalCer. CD1d-restricted T cells in the peripheral blood and CD1d-restricted T cell clones expressed high levels of CXCR3, CCR5, and CCR6; intermediate levels of CXCR4 and CXCR6; and low levels of CXCR1, CCR1, CCR2, and CX(3)CR1, a receptor pattern often associated with tissue-infiltrating effector Th1 cells and CD8+ T cells. Very few of these cells expressed the lymphoid-homing receptors CCR7 or CXCR5. CCR4 was expressed predominantly on CD4+, but not on double-negative CD1d-restricted T cells, which may indicate differential trafficking patterns for these two functionally distinct subsets. CD1d-restricted T cell clones responded to chemokine ligands for CXCR1/2, CXCR3, CXCR4, CXCR6, CCR4, and CCR5 in calcium flux and/or chemotaxis assays. These data indicate that CD1d-restricted T cells express a chemokine receptor profile most similar to Th1 inflammatory homing cells and suggest that these cells perform their function in peripheral tissue sites rather than in secondary lymphoid organs.
Tager, A. M. and A. D. Luster (2003). "BLT1 and BLT2: the leukotriene B(4) receptors." Prostaglandins Leukot Essent Fatty Acids 69(2-3): 123-34.
Two receptors for leukotriene B(4) (LTB(4)) have been molecularly identified: BLT1 and BLT2. Both receptors are G protein-coupled seven transmembrane domain receptors, whose genes are located in very close proximity to each other in the human and mouse genomes. The two receptors differ in their affinity and specificity for LTB(4): BLT1 is a high-affinity receptor specific for LTB(4), whereas BLT2 is a low-affinity receptor that also binds other eicosanoids. The two receptors also differ in their pattern of expression with BLT1 being expressed primarily in leukocytes, whereas BLT2 is expressed more ubiquitously. By mediating the activities of LTB(4), these receptors participate both in host immune responses and in the pathogenesis of inflammatory diseases. Reduced disease severity in animal inflammatory models seen with LTB(4) receptor antagonists and in mice with targeted deletion of BLT1 have revealed important roles for LTB(4) and its receptors in regulating pathologic inflammation.
Tager, A. M., S. K. Bromley, et al. (2003). "Leukotriene B(4) receptor BLT1 mediates early effector T cell recruitment." Nat Immunol.
Leukotriene B(4) (LTB(4)) was originally described as a potent lipid myeloid cell chemoattractant, rapidly generated from innate immune cells, that activates leukocytes through the G protein-coupled receptor BLT1. We report here that BLT1 is expressed on effector CD4(+) T cells generated in vitro as well as in vivo when effector T cells migrate out of the lymphoid compartment and are recruited into peripheral tissues. BLT1 mediated LTB(4)-induced T helper type 1 (T(H)1) and T(H)2 cell chemotaxis and firm adhesion to endothelial cells under flow, as well as early CD4(+) and CD8(+) T cell recruitment into the airway in an asthma model. Our findings show that the LTB(4)-BLT1 pathway is involved in linking early immune system activation and early effector T cell recruitment.
Swaminathan, G. J., D. E. Holloway, et al. (2003). "Crystal structures of oligomeric forms of the IP-10/CXCL10 chemokine." Structure (Camb) 11(5): 521-32.
We have determined the structure of wild-type IP-10 from three crystal forms. The crystals provide eight separate models of the IP-10 chain, all differing substantially from a monomeric IP-10 variant examined previously by NMR spectroscopy. In each crystal form, IP-10 chains form conventional beta sheet dimers, which, in turn, form a distinct tetrameric assembly. The M form tetramer is reminiscent of platelet factor 4, whereas the T and H forms feature a novel twelve-stranded beta sheet. Analytical ultracentrifugation indicates that, in free solution, IP-10 exists in a monomer-dimer equilibrium with a dissociation constant of 9 microM. We propose that the tetrameric structures may represent species promoted by the binding of glycosaminoglycans. The binding sites for several IP-10-neutralizing mAbs have also been mapped.
Means, T. K., F. Hayashi, et al. (2003). "The Toll-like receptor 5 stimulus bacterial flagellin induces maturation and chemokine production in human dendritic cells." J Immunol 170(10): 5165-75.
Toll-like receptors (TLRs) are pattern recognition receptors that serve an important function in detecting pathogens and initiating inflammatory responses. Upon encounter with foreign Ag, dendritic cells (DCs) go through a maturation process characterized by an increase in surface expression of MHC class II and costimulatory molecules, which leads to initiation of an effective immune response in naive T cells. The innate immune response to bacterial flagellin is mediated by TLR5, which is expressed on human DCs. Therefore, we sought to investigate whether flagellin could induce DC maturation. Immature DCs were cultured in the absence or presence of flagellin and monitored for expression of cell surface maturation markers. Stimulation with flagellin induced increased surface expression of CD83, CD80, CD86, MHC class II, and the lymph node-homing chemokine receptor CCR7. Flagellin stimulated the expression of chemokines active on neutrophils (IL-8/CXC chemokine ligand (CXCL)8, GRO-alpha/CXCL1, GRO-beta/CXCL2, GRO-gamma/CXCL3), monocytes (monocyte chemoattractant protein-1/CC chemokine ligand (CCL)2), and immature DCs (macrophage-inflammatory protein-1 alpha/CCL3, macrophage-inflammatory protein-1 beta/CCL4), but not chemokines active on effector T cells (IFN-inducible protein-10 kDa/CXCL10, monokine induced by IFN-gamma/CXCL9, IFN-inducible T cell alpha chemoattractant/CXCL11). However, stimulating DCs with both flagellin and IFN-inducible protein-10 kDa, monokine induced by IFN-gamma, and IFN-inducible T cell alpha chemoattractant expression, whereas stimulation with IFN-beta or flagellin alone failed to induce these chemokines. In functional assays, flagellin-matured DCs displayed enhanced T cell stimulatory activity with a concomitant decrease in endocytic activity. Finally, DCs isolated from mouse spleens or bone marrows were shown to not express TLR5 and were not responsive to flagellin stimulation. These results demonstrate that flagellin can directly stimulate human but not murine DC maturation, providing an additional mechanism by which motile bacteria can initiate an acquired immune response.
Lee, B. C., T. Cheng, et al. (2003). "P2Y-like receptor, GPR105 (P2Y14), identifies and mediates chemotaxis of bone-marrow hematopoietic stem cells." Genes Dev 17(13): 1592-604.
Hematopoiesis in mammals undergoes a developmental shift in location from fetal liver to bone marrow accompanied by a gradual transition from highly proliferative to deeply quiescent stem cell populations. P2Y receptors are G-protein-coupled nucleotide receptors participating in vascular and immune responses to injury. We identified a P2Y-like receptor for UDP-conjugated sugars, GPR105 (P2Y14), with restricted expression on primitive cells in the hematopoietic lineage. Anti-GPR105 antibody selectively isolated a subset of hematopoietic cells within the fetal bone marrow, but not in the fetal liver, that was enriched for G0 cell cycle status and for in vitro stem-cell-like multipotential long-term culture capability. Conditioned media from bone marrow stroma induced receptor activation and chemotaxis that was sensitive to G alpha i and anti-receptor antibody inhibition. GPR105 is a G-protein-coupled receptor identifying a quiescent, primitive population of hematopoietic cells restricted to bone marrow. It mediates primitive cell responses to specific hematopoietic microenvironments and extends the known immune system functions of P2Y receptors to the stem cell level. These data suggest a new class of receptors participating in the regulation of the stem cell compartment.
Hayashi, F., T. K. Means, et al. (2003). "Toll-like receptors stimulate human neutrophil function." Blood.
The first immune cell to arrive at the site of infection is the neutrophil. Upon arrival, neutrophils quickly initiate microbicidal functions, including the production of anti-microbial products and pro-inflammatory cytokines that serve to contain infection. This allows the acquired immune system enough time to generate sterilizing immunity and memory. Neutrophils detect the presence of a pathogen through germ-line encoded receptors that recognize microbe-associated molecular patterns. In vertebrates, the best characterized of these receptors are Toll-like Receptors (TLRs). We have determined the expression and function of TLRs in freshly isolated human neutrophils. Neutrophils expressed TLR1, 2, 4, 5, 6, 7, 8, 9, and 10 - all TLRs except for TLR3. GM-CSF treatment increased TLR2 and TLR9 expression levels. The agonists of all TLRs expressed in neutrophils triggered or primed cytokine release, superoxide generation, and L-selectin shedding, while inhibiting chemotaxis to IL-8 and increasing phagocytosis of opsonized latex beads. The response to the TLR9 agonist CpG DNA required GM-CSF pretreatment, which also enhanced the response to the other TLR agonists. Finally, using quantitative PCR, we demonstrate a chemokine expression profile that suggests that TLR-stimulated neutrophils recruit innate, but not acquired, immune cells to sites of infection.
Goodarzi, K., M. Goodarzi, et al. (2003). "Leukotriene B(4) and BLT1 control cytotoxic effector T cell recruitment to inflamed tissues." Nat Immunol.
Leukotriene B(4) (LTB(4)) is a potent chemoattractant for myeloid leukocytes, which express BLT1, the high-affinity receptor for LTB(4). We report here that BLT1 is induced substantially in CD8(+) effector T cells and at lower amounts in CD8(+) central memory T cells. LTB(4) elicited BLT1-dependent chemotaxis in effector cells, but not in naive or central memory cells. Intravital microscopy showed that BLT1 signaling induced rapid integrin-mediated arrest of rolling effector and central memory cells in postcapillary venules. In competitive homing experiments, wild-type effector cells were three times more efficient at migrating to the inflamed peritoneal cavity than were BLT-deficient effector cells. These results identify LTB(4)-BLT1 as a potent nonchemokine pathway for cytotoxic effector cell traffic.
Gillessen, S., Y. N. Naumov, et al. (2003). "CD1d-restricted T cells regulate dendritic cell function and antitumor immunity in a granulocyte-macrophage colony-stimulating factor-dependent fashion." Proc Natl Acad Sci U S A 100(15): 8874-9.
CD1d-restricted T cells contribute to tumor protection, but their precise roles remain unclear. Here we show that tumor cells engineered to secrete granulocyte-macrophage colony-stimulating factor induce the expansion of CD1d-restricted T cells through a mechanism that involves CD1d and macrophage inflammatory protein 2 expression by CD8 alpha-, CD11c+ dendritic cells (DCs). The antitumor immunity stimulated by vaccination with irradiated, granulocyte-macrophage colony-stimulating factor-secreting tumor cells was abrogated in CD1d- and J alpha 281-deficient mice, revealing a critical role for CD1d-restricted T cells in this response. The loss of antitumor immunity was associated with impaired tumor-induced T helper 2 cytokine production, although IFN-gamma secretion and cytotoxicity were preserved. DCs from immunized CD1d-deficient mice showed compromised maturation and function. Together, these results delineate a role for CD1d-restricted T cell-DC cross talk in the shaping of antitumor immunity.
Geiben-Lynn, R., M. Kursar, et al. (2003). "HIV-1 antiviral activity of recombinant natural killer cell enhancing factors, NKEF-A and NKEF-B, members of the peroxiredoxin family." J Biol Chem 278(3): 1569-74.
CD8(+) T-cells are a major source for the production of non-cytolytic factors that inhibit HIV-1 replication. In order to characterize further these factors, we analyzed gene expression profiles of activated CD8(+) T-cells using a human cDNA expression array containing 588 human cDNAs. mRNA for the chemokine I-309 (CCL1), the cytokines granulocyte-macrophage colony-stimulating factor and interleukin-13, and natural killer cell enhancing factors (NKEF) -A and -B were up-regulated in bulk CD8(+) T-cells from HIV-1 seropositive individuals compared with seronegative individuals. Recombinant NKEF-A and NKEF-B inhibited HIV-1 replication when exogenously added to acutely infected T-cells at an ID(50) (dose inhibiting HIV-1 replication by 50%) of approximately 130 nm (3 microg/ml). Additionally, inhibition against dual-tropic simian immunodeficiency virus and dual-tropic simian-human immunodeficiency virus was found. T-cells transfected with NKEF-A or NKEF-B cDNA were able to inhibit 80-98% HIV-1 replication in vitro. Elevated plasma levels of both NKEF-A and NKEF-B proteins were detected in 23% of HIV-infected non-treated individuals but not in persons treated with highly active antiviral therapy or uninfected persons. These results indicate that the peroxiredoxin family members NKEF-A and NKEF-B are up-regulated in activated CD8(+) T-cells in HIV infection, and suggest that these antioxidant proteins contribute to the antiviral activity of CD8(+) T-cells.
Friedrich, E. B., A. M. Tager, et al. (2003). "Mechanisms of Leukotriene B4-Triggered Monocyte Adhesion." Arterioscler Thromb Vasc Biol.
OBJECTIVE: Leukotriene B4 (LTB4) has been implicated in the trafficking of monocytes to inflammatory pathologic conditions, such as transplant rejection and atherosclerosis. The aim of this study was to determine the mechanisms by which LTB4 contributes to monocyte capture from the circulation. METHODS AND RESULTS: In in vitro and in vivo vascular models, the lipid chemoattractant LTB4 was an equipotent agonist of monocyte adhesion compared with the chemokine monocyte chemoattractant protein-1 (MCP-1). Adenoviral gene transfer of specific endothelial adhesion molecules and blocking monoclonal antibody studies demonstrated that LTB4 triggers both beta1- and beta2-integrin-dependent adhesion. Flow cytometry studies suggested that changes in integrin avidity or affinity, rather than alterations of integrin surface expression, were responsible for the chemoattractant-triggered arrest. Surprisingly, in contrast to the peptide chemokine MCP-1, LTB4 did not activate the phosphoinositide 3-kinase pathway, which is a functionally critical step in chemokine-triggered effector functions. CONCLUSIONS: LTB4 is a potent trigger of monocyte adhesion under flow yet mediates its effects via pathways that appear to differ from peptide chemoattractants. A better understanding of the mechanisms of LTB4-induced monocyte trafficking might shed insight into disease pathogenesis and pinpoint critical steps for therapeutic intervention for multiple human inflammatory pathologic conditions.
El Khoury, J. B., K. J. Moore, et al. (2003). "CD36 mediates the innate host response to beta-amyloid." J Exp Med 197(12): 1657-66.
Accumulation of inflammatory microglia in Alzheimer's senile plaques is a hallmark of the innate response to beta-amyloid fibrils and can initiate and propagate neurodegeneration characteristic of Alzheimer's disease (AD). The molecular mechanism whereby fibrillar beta-amyloid activates the inflammatory response has not been elucidated. CD36, a class B scavenger receptor, is expressed on microglia in normal and AD brains and binds to beta-amyloid fibrils in vitro. We report here that microglia and macrophages, isolated from CD36 null mice, had marked reductions in fibrillar beta-amyloid-induced secretion of cytokines, chemokines, and reactive oxygen species. Intraperitoneal and stereotaxic intracerebral injection of fibrillar beta-amyloid in CD36 null mice induced significantly less macrophage and microglial recruitment into the peritoneum and brain, respectively, than in wild-type mice. Our data reveal that CD36, a major pattern recognition receptor, mediates microglial and macrophage response to beta-amyloid, and imply that CD36 plays a key role in the proinflammatory events associated with AD.
Campanella, G. S., E. M. Lee, et al. (2003). "CXCR3 and heparin binding sites of the chemokine IP-10 (CXCL10)." J Biol Chem 278(19): 17066-74.
The chemokine IP-10 (interferon-inducible protein of 10 kDa, CXCL10) binds the G protein-coupled receptor CXCR3, which is found mainly on activated T cells and NK cells, and plays an important role in Th1-type inflammatory diseases. IP-10 also binds to glycosaminoglycans (GAGs), an interaction thought to be important for its sequestration on endothelial and other cells. In this study, we performed an extensive mutational analysis to identify the CXCR3 and heparin binding sites of murine IP-10. The mutants were characterized for heparin binding, CXCR3 binding, and the ability to induce chemotaxis, Ca(2+) flux, and CXCR3 internalization. Double mutations neutralizing adjacent basic residues at the C terminus did not lead to a significant reduction in heparin binding, indicating that the main heparin binding site of IP-10 is not along the C-terminal alpha helix. Alanine exchange of Arg-22 had the largest effect on heparin binding, with residues Arg-20, Ile-24, Lys-26, Lys-46, and Lys-47 further contributing to heparin binding. A charge change mutation of Arg-22 resulted in further reduction in heparin binding. The N-terminal residue Arg-8, preceding the first cysteine, was critical for CXCR3 signaling. Mutations of charged and uncharged residues in the loop regions of residues 20-24 and 46-47, which caused reduced heparin binding, also resulted in reduced CXCR3 binding and signaling. CXCR3 expressing GAG-deficient Chinese hamster ovary cells revealed that GAG binding was not required for IP-10 binding and signaling through CXCR3, which suggests that the CXCR3 and heparin binding sites of IP-10 are partially overlapping.
Abdi, R., T. K. Means, et al. (2003). "Chemokines in islet allograft rejection." Diabetes Metab Res Rev 19(3): 186-90.
Chemokines have emerged as important regulators in the development, differentiation, and anatomic distribution of leukocytes. Studies of renal and cardiac allograft biopsies have revealed that the expression of many chemokine receptors and their ligands was associated with acute allograft rejection. However, the importance of these chemokine receptor systems varies in the host response to a particular allograft. In this regard, CXCR3 appears to play a more important role in cardiac allograft rejection than CCR2 and CCR5. We have found that CCR2, CCR5, and CXCR3 and their ligands, as well as Th1 cytokines are induced to high levels in rejecting islet allografts. Interestingly, targeting CCR5 resulted in a significant prolongation of islet allograft survival. This prolongation was associated with a Th2 response. Our data indicate that in the process of acute rejection, the temporal expression and the ultimate function of a given chemokine vary among different organs or tissues. Hence, each organ or tissue may require a unique set of chemokines to generate acute rejection. Targeting the appropriate chemokine receptors may provide a clinically useful strategy to prevent islet allograft rejection.
Zhao, D. X., Y. Hu, et al. (2002). "Differential expression of the IFN-gamma-inducible CXCR3-binding chemokines, IFN-inducible protein 10, monokine induced by IFN, and IFN-inducible T cell alpha chemoattractant in human cardiac allografts: association with cardiac allograft vasculopathy and acute rejection." J Immunol 169(3): 1556-60.
CXCR3 chemokines exert potent biological effects on both immune and vascular cells. The dual targets suggest their important roles in cardiac allograft vasculopathy (CAV) and rejection. Therefore, we investigated expression of IFN-inducible protein 10 (IP-10), IFN-inducible T cell alpha chemoattractant (I-TAC), monokine induced by IFN (Mig), and their receptor CXCR3 in consecutive endomyocardial biopsies (n = 133) from human cardiac allografts and corresponding normal donor hearts (n = 11) before transplantation. Allografts, but not normal hearts, contained IP-10, Mig, and I-TAC mRNA. Persistent elevation of IP-10 and I-TAC was associated with CAV. Allografts with CAV had an IP-10-GAPDH ratio 3.7 +/- 0.8 compared with 0.8 +/- 0.2 in those without CAV (p = 0.004). Similarly, I-TAC mRNA levels were persistently elevated in allografts with CAV (6.7 +/- 1.9 in allografts with vs 1.5 +/- 0.3 in those without CAV, p = 0.01). In contrast, Mig mRNA was induced only during rejection (2.4 +/- 0.9 with vs 0.6 +/- 0.2 without rejection, p = 0.015). In addition, IP-10 mRNA increased above baseline during rejection (4.1 +/- 2.3 in rejecting vs 1.8 +/- 1.2 in nonrejecting biopsies, p = 0.038). I-TAC did not defer significantly with rejection. CXCR3 mRNA persistently elevated after cardiac transplantation. Double immunohistochemistry revealed differential cellular distribution of CXCR3 chemokines. Intragraft vascular cells expressed high levels of IP-10 and I-TAC, while Mig localized predominantly in infiltrating macrophages. CXCR3 was localized in vascular and infiltrating cells. CXCR3 chemokines are induced in cardiac allografts and differentially associated with CAV and rejection. Differential cellular distribution of these chemokines in allografts indicates their central roles in multiple pathways involving CAV and rejection. This chemokine pathway may serve as a monitor and target for novel therapies to prevent CAV and rejection.
Zhang, Z., L. Kaptanoglu, et al. (2002). "Donor T cell activation initiates small bowel allograft rejection through an IFN-gamma-inducible protein-10-dependent mechanism." J Immunol 168(7): 3205-12.
The poor success in controlling small bowel (SB) allograft rejection is partially attributed to the unique immune environment in the donor intestine. We hypothesized that Ag-induced activation of donor-derived T cells contributes to the initiation of SB allograft rejection. To address the role of donor T cell activation in SB transplantation, SB grafts from DO11.10 TCR transgenic mice (BALB/c, H-2L(d+)) were transplanted into BALB/c (isografts), or single class I MHC-mismatched (L(d)-deficient) BALB/c H-2(dm2) (dm2, H-2L(d-)) mutant mice (allografts). Graft survival was followed after injection of control or antigenic OVA(323-339) peptide. Eighty percent of SB allografts developed severe rejection in mice treated with antigenic peptide, whereas <20% of allografts were rejected in mice treated with control peptide (p < 0.05). Isografts survived >30 days regardless of OVA(323-339) administration. Activation of donor T cells increased intragraft expression of proinflammatory cytokine (IFN-gamma) and CXC chemokine IFN-gamma-inducible protein-10 mRNA and enhanced activation and accumulation of host NK and T cells in SB allografts. Treatment of mice with neutralizing anti-IFN-gamma-inducible protein-10 mAb increased SB allograft survival in Ag-treated mice (67%; p < 0.05) and reduced accumulation of host T cells and NK cells in the lamina propria but not mesenteric lymph nodes. These results suggest that activation of donor T cells after SB allotransplantation induces production of a Th1-like profile of cytokines and CXC chemokines that enhance infiltration of host T cells and NK cells in SB allografts. Blocking this pathway may be of therapeutic value in controlling SB allograft rejection.
Yang, O. O., E. A. Garcia-Zepeda, et al. (2002). "Monocyte chemoattractant protein-2 (CC chemokine ligand 8) inhibits replication of human immunodeficiency virus type 1 via CC chemokine receptor 5." J Infect Dis 185(8): 1174-8.
CC chemokine receptor 5 (CCR5) is a coreceptor for cellular entry of monocyte-tropic (R5) strains of human immunodeficiency virus (HIV) type 1, which has been implicated as the predominant phenotype of HIV in early infection. The CCR5 agonists macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and RANTES (regulated on activation, normally T cell-expressed and -secreted) have been shown to block replication of R5 virus in vitro and have gained attention as potential antiviral factors. However, a few reports have suggested that other chemokines may also block R5 HIV-1, including monocyte chemoattractant protein (MCP)-2 (CC chemokine ligand 8). We demonstrate that MCP-2 specifically inhibits replication of R5 HIV-1 and that this activity is additive to that of RANTES. Furthermore, MCP-2 induces a robust, pertussis toxin-sensitive calcium flux in primary lymphocytes, and cross-desensitization studies indicate that MCP-2 acts via CCR5. These data confirm that MCP-2 is a ligand for CCR5 on CD4(+) lymphocytes and can specifically block R5 HIV-1.
Poznansky, M. C., I. T. Olszak, et al. (2002). "Thymocyte emigration is mediated by active movement away from stroma-derived factors." J Clin Invest 109(8): 1101-10.
T cells leave the thymus at a specific time during differentiation and do not return despite elaboration of known T cell chemoattractants by thymic stroma. We observed differentiation stage-restricted egress of thymocytes from an artificial thymus in which vascular structures or hemodynamics could not have been playing a role. Hypothesizing that active movement of cells away from a thymic product may be responsible, we demonstrated selective reduction in emigration from primary thymus by inhibitors of active movement down a concentration gradient (chemofugetaxis). Immature intrathymic precursors were insensitive to an emigration signal, whereas mature thymocytes and peripheral blood T cells were sensitive. Thymic stroma was noted to elaborate at least two proteins capable of inducing emigration, one of which was stromal cell-derived factor-1. Thymic emigration is mediated, at least in part, by specific fugetaxis-inducing factors to which only mature cells respond.
Moore, K. J., J. El Khoury, et al. (2002). "A CD36-initiated signaling cascade mediates inflammatory effects of beta-amyloid." J Biol Chem 277(49): 47373-9.
beta-Amyloid accumulation is associated with pathologic changes in the brain in Alzheimer's disease and has recently been identified in plaques of another chronic inflammatory disorder, atherosclerosis. The class B scavenger receptor, CD36, mediates binding of fibrillar beta-amyloid to cells of the monocyte/macrophage lineage, including brain macrophages (microglia). In this study, we demonstrate that in microglia and other tissue macrophages, beta-amyloid initiates a CD36-dependent signaling cascade involving the Src kinase family members, Lyn and Fyn, and the mitogen-activated protein kinase, p44/42. Interruption of this signaling cascade, through targeted disruption of Src kinases downstream of CD36, inhibits macrophage inflammatory responses to beta-amyloid, including reactive oxygen and chemokine production, and results in decreased recruitment of microglia to sites of amyloid deposition in vivo. The finding that engagement of CD36 by beta-amyloid initiates a Src kinase-dependent production of inflammatory mediators in cells of the macrophage lineage reveals a novel receptor-mediated pro-inflammatory signaling pathway of potential therapeutic importance.
Medoff, B. D., A. Sauty, et al. (2002). "IFN-gamma-inducible protein 10 (CXCL10) contributes to airway hyperreactivity and airway inflammation in a mouse model of asthma." J Immunol 168(10): 5278-86.
Allergic asthma is an inflammatory disease of the airways characterized by eosinophilic inflammation and airway hyper-reactivity. Cytokines and chemokines specific for Th2-type inflammation predominate in asthma and in animal models of this disease. The role of Th1-type inflammatory mediators in asthma remains controversial. IFN-gamma-inducible protein 10 (IP-10; CXCL10) is an IFN-gamma-inducible chemokine that preferentially attracts activated Th1 lymphocytes. IP-10 is up-regulated in the airways of asthmatics, but its function in asthma is unclear. To investigate the role of IP-10 in allergic airway disease, we examined the expression of IP-10 in a murine model of asthma and the effects of overexpression and deletion of IP-10 in this model using IP-10-transgenic and IP-10-deficient mice. Our experiments demonstrate that IP-10 is up-regulated in the lung after allergen challenge. Mice that overexpress IP-10 in the lung exhibited significantly increased airway hyperreactivity, eosinophilia, IL-4 levels, and CD8(+) lymphocyte recruitment compared with wild-type controls. In addition, there was an increase in the percentage of IL-4-secreting T lymphocytes in the lungs of IP-10-transgenic mice. In contrast, mice deficient in IP-10 demonstrated the opposite results compared with wild-type controls, with a significant reduction in these measures of Th2-type allergic airway inflammation. Our results demonstrate that IP-10, a Th1-type chemokine, is up-regulated in allergic pulmonary inflammation and that this contributes to the airway hyperreactivity and Th2-type inflammation seen in this model of asthma.
Mathew, A., B. D. Medoff, et al. (2002). "Cutting edge: Th2 cell trafficking into the allergic lung is dependent on chemoattractant receptor signaling." J Immunol 169(2): 651-5.
Th2 cells are recruited to the lung where they mediate the asthma phenotype. Since the molecular mechanisms regulating Th2 cell trafficking remain unknown, we sought to determine whether trafficking of Th2 cells into the lung is mediated by G alpha i-coupled chemoattractant receptors. We show here that in contrast to untreated Th2 cells, pertussis toxin-treated Th2 cells were unable to traffic into the lung, airways, or lymph nodes following Ag challenge and therefore were unable to induce allergic inflammation in vivo. Pertussis toxin-treated Th2 cells were functional cells, however, and when directly instilled into the airways of mice, bypassing their need to traffic to the lung, were able to induce airway eosinophilic inflammation. These studies conclusively demonstrate that trafficking of Th2 cells into the lung is an active process dependent on chemoattractant receptors.
Luster, A. D. (2002). "The role of chemokines in linking innate and adaptive immunity." Curr Opin Immunol 14(1): 129-35.
It is becoming clear that chemokine function is necessary to translate an innate-immune response into an acquired response. Dendritic cells activated by innate stimuli and loaded with foreign antigen travel to regional lymph nodes to activate the acquired-immune system. Subsequently, the activated acquired-immune cells move into tissue, where the innate immune system sets-off the danger signal. The chemokine system has emerged as an essential regulator of this dendritic cell and lymphocyte trafficking, which is necessary to turn an innate immune response into an adaptive response.
Izikson, L., R. S. Klein, et al. (2002). "Targeting monocyte recruitment in CNS autoimmune disease." Clin Immunol 103(2): 125-31.
Monocytes and macrophages play a pathogenic role in a number of autoimmune inflammatory diseases. Recent studies in experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis, have identified a critical chemokine-mediated mechanism of monocyte homing to the central nervous system (CNS). Here, we summarize the current findings in EAE, develop a rationale for targeting the chemokine axis in order to treat CNS inflammatory disease, and review currently available molecule-specific therapeutics that inhibit monocyte trafficking to the CNS.
Geiben-Lynn, R., N. Brown, et al. (2002). "Purification of a modified form of bovine antithrombin III as an HIV-1 CD8+ T-cell antiviral factor." J Biol Chem 277(44): 42352-7.
CD8(+) T-cells secrete soluble factor(s) capable of inhibiting both R5- and X4-tropic strains of human immunodeficiency virus type 1 (HIV-1). CCR5 chemokine ligands, released from activated CD8(+) T-cells, contribute to the antiviral activity of these cells. These CC-chemokines, however, do not account for all CD8(+) T-cell antiviral factor(s) (CAF) released from these cells, particularly because the elusive CAF can inhibit the replication of X4 HIV-1 strains that use CXCR4 and not CCR5 as a coreceptor. Here we demonstrate that activated CD8(+) T-cells of HIV-1-seropositive individuals modify serum bovine antithrombin III into an HIV-1 inhibitory factor capable of suppressing the replication of X4 HIV-1. These data indicate that antithrombin III may play a role in the progression of HIV-1 disease.
Dufour, J. H., M. Dziejman, et al. (2002). "IFN-gamma-inducible protein 10 (IP-10; CXCL10)-deficient mice reveal a role for IP-10 in effector T cell generation and trafficking." J Immunol 168(7): 3195-204.
IFN-gamma-inducible protein 10 (IP-10, CXCL10), a chemokine secreted from cells stimulated with type I and II IFNs and LPS, is a chemoattractant for activated T cells. Expression of IP-10 is seen in many Th1-type inflammatory diseases, where it is thought to play an important role in recruiting activated T cells into sites of tissue inflammation. To determine the in vivo function of IP-10, we constructed an IP-10-deficient mouse (IP-10(-/-)) by targeted gene disruption. Immunological analysis revealed that IP-10(-/-) mice had impaired T cell responses. T cell proliferation to allogeneic and antigenic stimulation and IFN-gamma secretion in response to antigenic challenge were impaired in IP-10(-/-) mice. In addition, IP-10(-/-) mice exhibited an impaired contact hypersensitivity response, characterized by decreased ear swelling and reduced inflammatory cell infiltrates. T cells recovered from draining lymph nodes also had a decreased proliferative response to Ag restimulation. Furthermore, IP-10(-/-) mice infected with a neurotropic mouse hepatitis virus had an impaired ability to control viral replication in the brain. This was associated with decreased recruitment of CD4(+) and CD8(+) lymphocytes into the brain, reduced levels of IFN-gamma and the IFN-gamma-induced chemokines monokine induced by IFN-gamma (Mig, CXCL9) and IFN-inducible T cell alpha chemoattractant (I-TAC, CXCL11) in the brain, decreased numbers of virus-specific IFN-gamma-secreting CD8(+) cells in the spleen, and reduced levels of demyelination in the CNS. Taken together, our data suggest a role for IP-10 in both effector T cell generation and trafficking in vivo.
Coraci, I. S., J. Husemann, et al. (2002). "CD36, a class B scavenger receptor, is expressed on microglia in Alzheimer's disease brains and can mediate production of reactive oxygen species in response to beta-amyloid fibrils." Am J Pathol 160(1): 101-12.
A pathological hallmark of Alzheimer's disease is the senile plaque, composed of beta-amyloid fibrils, microglia, astrocytes, and dystrophic neurites. We reported previously that class A scavenger receptors mediate adhesion of microglia and macrophages to beta-amyloid fibrils and oxidized low-density lipoprotein (oxLDL)-coated surfaces. We also showed that CD36, a class B scavenger receptor and an oxLDL receptor, promotes H(2)O(2) secretion by macrophages adherent to oxLDL-coated surfaces. Whether CD36 is expressed on microglia, and whether it plays a role in secretion of H(2)O(2) by microglia interacting with fibrillar beta-amyloid is not known. Using fluorescence-activated cell sorting analysis and immunohistochemistry, we found that CD36 is expressed on human fetal microglia, and N9-immortalized mouse microglia. We also found that CD36 is expressed on microglia and on vascular endothelial cells in the brains of Alzheimer's disease patients. Bowes human melanoma cells, which normally do not express CD36, gained the ability to specifically bind to surfaces coated with fibrillar beta-amyloid when transfected with a cDNA encoding human CD36, suggesting that CD36 is a receptor for fibrillar beta-amyloid. Furthermore, two different monoclonal antibodies to CD36 inhibited H(2)O(2) production by N9 microglia and human macrophages adherent to fibrillar beta-amyloid by approximately 50%. Our data identify a role for CD36 in fibrillar beta-amyloid-induced H(2)O(2) production by microglia, and imply that CD36 can mediate binding to fibrillar beta-amyloid. We propose that similar to their role in the interaction of macrophages with oxLDL, class A scavenger receptors and CD36 play complimentary roles in the interactions of microglia with fibrillar beta-amyloid.
Abdi, R., R. N. Smith, et al. (2002). "The role of CC chemokine receptor 5 (CCR5) in islet allograft rejection." Diabetes 51(8): 2489-95.
Chemokines are important regulators in the development, differentiation, and anatomic location of leukocytes. CC chemokine receptor 5 (CCR5) is expressed preferentially by CD4(+) T helper 1 (Th1) cells. We sought to determine the role of CCR5 in islet allograft rejection in a streptozotocin-induced diabetic mouse model. BALB/c islet allografts transplanted into CCR5(-/-) (C57BL/6) recipients survived significantly longer (mean survival time, 38 +/- 8 days) compared with those transplanted into wild-type control mice (10 +/- 2 days; P < 0.0001). Twenty percent of islet allografts in CCR5(-/-) animals without other treatment survived >90 days. In CCR5(-/-) mice, intragraft mRNA expression of interleukin-4 and -5 was increased, whereas that of interferon-gamma was decreased, corresponding to a Th2 pattern of T-cell activation in the target tissues compared with a Th1 pattern observed in controls. A similar Th2 response pattern was also observed in the periphery (splenocytes responding to donor cells) by enzyme-linked immunosorbent spot assay. We conclude that CCR5 plays an important role in orchestrating the Th1 immune response leading to islet allograft rejection. Targeting this chemokine receptor, therefore, may provide a clinically useful strategy to prevent islet allograft rejection.
Tateno, H., H. Nakamura, et al. (2001). "Eotaxin and monocyte chemoattractant protein-1 in chronic eosinophilic pneumonia." Eur Respir J 17(5): 962-8.
Chronic eosinophilic pneumonia (CEP) is characterized by chronic or recurrent pulmonary infiltrates with eosinophils, but the precise mechanism of eosinophil accumulation has not been fully elucidated. Eotaxin is one of the CC chemokines that selectively recruits eosinophils and contributes to the pathogenesis of allergic airway diseases including asthma, but its roles in pathogenesis of CEP have not been fully elucidated. The authors measured concentrations of eotaxin and other CC chemokines, monocyte chemoattractant protein-1 (MCP-1), regulated on activation, normal T-cell expressed and secreted, macrophage inflammatory protein-1alpha, and the eosinophil activating Th2 cytokine interleukin (IL)-5 in bronchoalveolar lavage (BAL) fluid from CEP patients (n=11), and compared these concentrations with those from control subjects (n = 6). The eotaxin (904 +/- 203 versus 29 +/- 7 pg x mL(-1), p = 0.0001), MCP-1 (194 +/- 57 versus 15 +/- 2 pg x mL(-1), p < 0.05), and IL-5 (7.8 +/- 2.0 versus 2.7 +/- 0.6 pg x mL(-1), p < 0.05) levels were significantly higher for cases with CEP in comparison to those serving as controls. Proportions of eosinophil and lymphocyte counts were greater in BAL fluid from CEP patients. Eotaxin and IL-5 levels correlated with the proportion of eosinophils in BAL fluid from CEP patients. MCP-1 correlated with the relative lymphocyte numbers. In short, eotaxin, interleukin-5, and monocyte chemoattractant protein-1 levels were higher in the BAL fluid of CEP patients and these levels may contribute to eosinophil and lymphocyte recruitment and activation in the airways as found with this disorder.
Shen, H., T. Cheng, et al. (2001). "CXCR-4 desensitization is associated with tissue localization of hemopoietic progenitor cells." J Immunol 166(8): 5027-33.
The chemokine stroma-derived factor (SDF)-1, and its receptor, CXCR-4, have been shown to be essential for the translocation of hemopoietic stem cells from the fetal liver to the bone marrow (BM). We hypothesized that if CXCR-4 plays a crucial role in the localization of human hemopoiesis, stem cells from distinct tissue sources should demonstrate distinct CXCR-4 expression or signaling profiles. CD34(+) cells from BM were compared with blood: either mobilized peripheral blood or umbilical cord blood. Unexpectedly, significantly higher levels of CXCR-4 surface expression on CD34(+) cells from blood sources, mobilized peripheral blood, or cord blood were observed compared with BM (p = 0.0005 and p = 0.002, respectively). However, despite lower levels of CXCR-4, responsiveness of the cells to SDF-1 as measured by either calcium flux or transmigration was proportionally greatest in cells derived from BM. Further, internalization of CXCR-4 in response to ligand, associated with receptor desensitization, was significantly lower on BM-derived cells. Therefore, preserved chemokine receptor signaling was highly associated with marrow rather than blood localization. To test the functional effects of perturbing CXCR-4 signaling, adult mice were exposed to the methionine-SDF-1beta analog that induces prolonged down-regulation/desensitization of CXCR-4 and observed mobilization of Lin(-), Sca-1(+), Thy-1(low), and c-kit(+) hemopoietic progenitor cells to the peripheral blood with a >30-fold increase compared with PBS control (p = 0.0007 day 1 and p = 0.004 day 2). These data demonstrate that CXCR-4 expression and function can be dissociated in progenitor cells and that desensitization of CXCR-4 induces stem cell entry into the circulation.
Sauty, A., R. A. Colvin, et al. (2001). "CXCR3 internalization following T cell-endothelial cell contact: preferential role of IFN-inducible T cell alpha chemoattractant (CXCL11)." J Immunol 167(12): 7084-93.
Chemokine receptors are rapidly desensitized and internalized following ligand binding, a process that attenuates receptor-mediated responses. However, the physiological settings in which this process occurs are not clear. Therefore, we examined the fate of CXCR3, a chemokine receptor preferentially expressed on activated T cells following contact with endothelial cells. By immunofluorescence microscopy and flow cytometry, we found that CXCR3 was rapidly internalized when T cells were incubated with IFN-gamma-activated human saphenous vein endothelial cells (HSVEC), but not with resting HSVEC. Similar results were obtained using human CXCR3-transfected murine 300-19 B cells. CXCR3 down-regulation was significantly more pronounced when T cells were in contact with HSVEC than with their supernatants, suggesting that CXCR3 ligands were efficiently displayed on the surface of HSVEC. Using neutralizing mAbs to IFN-induced protein-10 (CXCL10), monokine induced by IFN-gamma (CXCL9), and IFN-inducible T cell alpha chemoattractant (I-TAC; CXCL11), we found that even though I-TAC was secreted from IFN-gamma-activated HSVEC to lower levels than IFN-induced protein-10 or the monokine induced by IFN-gamma, it was the principal chemokine responsible for CXCR3 internalization. This correlated with studies using recombinant chemokines, which revealed that I-TAC was the most potent inducer of CXCR3 down-regulation and of transendothelial migration. Known inhibitors of chemokine-induced chemotaxis, such as pertussis toxin or wortmannin, did not reduce ligand-induced internalization, suggesting that a distinct signal transduction pathway mediates internalization. Our data demonstrate that I-TAC is the physiological inducer of CXCR3 internalization and suggest that chemokine receptor internalization occurs in physiological settings, such as leukocyte contact with an activated endothelium.
Pertl, U., A. D. Luster, et al. (2001). "IFN-gamma-inducible protein-10 is essential for the generation of a protective tumor-specific CD8 T cell response induced by single-chain IL-12 gene therapy." J Immunol 166(11): 6944-51.
The successful induction of T cell-mediated protective immunity against poorly immunogenic malignancies remains a major challenge for cancer immunotherapy. Here, we demonstrate that the induction of tumor-protective immunity by IL-12 in a murine neuroblastoma model depends entirely on the CXC chemokine IFN-gamma-inducible protein 10 (IP-10). This was established by in vivo depletion of IP-10 with mAbs in mice vaccinated against NXS2 neuroblastoma by gene therapy with a linearized, single-chain (sc) version of the heterodimeric cytokine IL-12 (scIL-12). The efficacy of IP-10 depletion was indicated by the effective abrogation of scIL-12-mediated antiangiogenesis and T cell chemotaxis in mice receiving s.c. injections of scIL-12-producing NXS2 cells. These findings were extended by data demonstrating that IP-10 is directly involved in the generation of a tumor-protective CD8+ T cell-mediated immune response during the early immunization phase. Four lines of evidence support this contention: First, A/J mice vaccinated with NXS2 scIL-12 and depleted of IP-10 by two different anti-IP-10 mAbs revealed an abrogation of systemic-protective immunity against disseminated metastases. Second, CD8+ T cell-mediated MHC class I Ag-restricted tumor cell lysis was inhibited in such mice. Third, intracellular IFN-gamma expressed by proliferating CD8+ T cells was substantially inhibited in IP-10-depleted, scIL-12 NXS2-vaccinated mice. Fourth, systemic tumor protective immunity was completely abrogated in mice depleted of IP-10 in the early immunization phase, but not if IP-10 was depleted only in the effector phase. These findings suggest that IP-10 plays a crucial role during the early immunization phase in the induction of immunity against neuroblastoma by scIL-12 gene therapy.
Nakamura, H., A. D. Luster, et al. (2001). "IL-4 differentially regulates eotaxin and MCP-4 in lung epithelium and circulating mononuclear cells." Am J Physiol Lung Cell Mol Physiol 281(5): L1288-302.
To investigate the mechanisms of eosinophil recruitment in allergic airway inflammation, we examined the effects of interleukin (IL)-4, a Th2-type cytokine, on eotaxin and monocyte chemoattractant protein-4 (MCP-4) expression in human peripheral blood mononuclear cells (PBMCs; n = 10), in human lower airway mononuclear cells (n = 5), in the human lung epithelial cell lines A549 and BEAS-2B, and in human cultured airway epithelial cells. IL-4 inhibited eotaxin and MCP-4 mRNA expression induced by IL-1 beta and tumor necrosis factor-alpha in PBMCs but did not significantly inhibit expression in epithelial cells. Eotaxin and MCP-4 mRNA expression was not significantly induced by proinflammatory cytokines in lower airway mononuclear cells. IL-1 beta-induced eotaxin and MCP-4 protein production was also inhibited by IL-4 in PBMCs, whereas IL-4 enhanced eotaxin protein production in A549 cells. In contrast, dexamethasone inhibited eotaxin and MCP-4 expression in both PBMCs and epithelial cells. The divergent effects of IL-4 on eotaxin and MCP-4 expression between PBMCs and epithelial cells may create chemokine concentration gradients between the subepithelial layer and the capillary spaces that may promote the recruitment of eosinophils to the airway in Th2-type responses.
Nakamura, H., A. D. Luster, et al. (2001). "Variant eotaxin: its effects on the asthma phenotype." J Allergy Clin Immunol 108(6): 946-53.
BACKGROUND: Eotaxin, a CC chemokine expressed in the asthmatic lung, has been associated with impaired lung function. The role of its variant form is unknown. OBJECTIVE: The purpose of this study was to detect the population frequency and effects of a known single-nucleotide polymorphism in the eotaxin gene in which a threonine residue (THR(23)) is substituted for the wild-type alanine (ALA(23)) at the 23rd amino acid at the terminus of the peptide leader sequence. METHODS: We measured eotaxin protein secretion in 293 cells transfected with expression vectors and in PBMCs obtained from individuals bearing the alternative forms of the gene. A case-control study of plasma eotaxin levels and eosinophil counts, a comparison of baseline lung function by genotype in a population of 806 subjects with asthma, and a comparison of the allele frequency with a nonasthmatic population were performed. RESULTS: Human 293 cells and PBMCs with THR(23) variant eotaxin secreted significantly less eotaxin protein than did ALA(23)-bearing cells. In the case-control study, THR(23)-THR(23) individuals had lower plasma levels of eotaxin (310 [240-350] vs 420 [270-700] pg/mL; P < .05) and eosinophil counts (120 [5-220] vs 190 [110-470] cells/microL; P < .05) than ALA(23)-ALA(23) subjects; heterozygous subjects had intermediate levels. Higher levels of lung function were associated with THR(23) eotaxin (percent of predicted FEV(1), 65% +/- 3.5% [THR(23)-THR(23)] vs 58% +/- 0.9% [THR(23)-ALA(23)] and 56% +/- 0.5% [ALA(23)-ALA(23)]; P < .05). CONCLUSION: The THR(23) variant is associated with both decreased eosinophil counts and higher levels of lung function in subjects with asthma.
Miotto, D., P. Christodoulopoulos, et al. (2001). "Expression of IFN-gamma-inducible protein; monocyte chemotactic proteins 1, 3, and 4; and eotaxin in TH1- and TH2-mediated lung diseases." J Allergy Clin Immunol 107(4): 664-70.
BACKGROUND: Chemokines are involved in the influx of leukocytes into the airways in inflammatory lung diseases. The differential cell recruitment characteristic of T(H)1 versus T(H)2 immune responses may be associated with differential chemokine expression. OBJECTIVE: We investigated the expression of chemokines; monocyte chemotactic proteins (MCPs) 1, 3, and 4; eotaxin; and IFN-gamma-inducible protein 10 (IP-10) in both T(H)1- and T(H)2-mediated lung diseases. METHODS: By using immunocytochemistry and in situ hybridization, we examined the protein and mRNA expression, respectively, in bronchoalveolar lavage and biopsy samples in subjects with asthma, tuberculosis, sarcoidosis, and chronic bronchitis. RESULTS: Increased immunoreactivity and mRNA expression of IP-10 and of the MCPs was found in the bronchoalveolar lavage fluid and biopsy specimens of subjects with asthma and tuberculosis compared with that of control subjects (P <.005). IP-10, however, was particularly increased in subjects with sarcoidosis (P <.001). Eotaxin, on the other hand, was increased only in patients with asthma when compared with control subjects (P <.005). CONCLUSION: This study demonstrates that MCP-1, MCP-3, and MCP-4 expression is not specifically associated with lung diseases characterized by a particular cytokine profile. In contrast, IP-10 is mostly expressed in T(H)1-mediated diseases, and eotaxin expression seems to be specifically associated with lung diseases of a T(H)2 cytokine profile.
Meyer, M., P. J. Hensbergen, et al. (2001). "Cross reactivity of three T cell attracting murine chemokines stimulating the CXC chemokine receptor CXCR3 and their induction in cultured cells and during allograft rejection." Eur J Immunol 31(8): 2521-7.
Recent work identified the murine gene homologous to the human T cell attracting chemokine CXC receptor ligand 11 (CXCL11, also termed I-TAC, SCYB11, ss-R1, H174, IP-9). Here, the biological activity and expression patterns of murine CXCL11 relative to CXCL9 (MIG) and CXCL10 (IP-10/crg-2), the other two CXCR3 ligands, were assessed. Calcium mobilization and chemotaxis experiments demonstrated that murine CXCL11 stimulated murine CXCR3 at much lower doses than murine CXCL9 or murine CXCL10. Murine CXCL11 also evoked calcium mobilization in CHO cells transfected with human CXCR3 and was chemotactic for CXCR3-expressing human T lymphocytes as well as for 300--19 pre-B cells transfected with human or murine CXCR3. Moreover, murine CXCL11 blocked the chemotactic effect of human CXCL11 on human CXCR3 transfectants. Depending on cell type (macrophage-like cells RAW264.7, J774A.1, fetal F20 and adult dermal fibroblasts, immature and mature bone marrow-derived dendritic cells) and stimulus (interferons, LPS, IL-1 beta and TNF-alpha), an up to 10,000-fold increase of CXCL9, CXCL10 and CXCL11 mRNA levels, quantified by real-time PCR, was observed. In vivo, the three chemokines are constitutively expressed in various tissues from healthy BALB/c mice and were strongly up-regulated during rejection of allogeneic heart transplants. Chemokine mRNA levels exceeded those of CXCR3 and IFN-gamma which were induced with similar kinetics by several orders of magnitude.
Mathew, A., J. A. MacLean, et al. (2001). "Signal transducer and activator of transcription 6 controls chemokine production and T helper cell type 2 cell trafficking in allergic pulmonary inflammation." J Exp Med 193(9): 1087-96.
Antigen-specific CD4 T helper type 2 (Th2) cells play a pivotal role in the induction of allergic asthma, but the mechanisms regulating their recruitment into the airways are unknown. Signal transducer and activator of transcription factor (Stat)6 is a transcription factor essential for Th2 cell differentiation. Here we show that Stat6 also controls Th2 cell recruitment and effector function in allergic inflammation in vivo. To isolate the role of Stat6 in regulating Th2 cell trafficking and effector function from its role in Th2 cell differentiation, we used a murine model of asthma in which in vitro-differentiated Stat6(+/+) antigen-specific Th2 cells were adoptively transferred into naive Stat6(-/-) and Stat6(+/+) mice followed by aerosol antigen challenge. We found that all of the features of asthma, including Th2 cell accumulation, Th2 and eosinophil-active chemokine production, and airway eosinophilia, mucus production, and hyperresponsiveness seen in Stat6(+/+) mice, were dramatically absent in Stat6(-/)- mice that received Stat6(+/)+ antigen-specific Th2 cells. Our findings establish Stat6 as essential for Th2 cell trafficking and effector function and suggest that interruption of Stat6 signaling in resident cells of the lung is a novel approach to asthma therapy.
Luster, A. D. (2001). "Chemokines regulate lymphocyte homing to the intestinal mucosa." Gastroenterology 120(1): 291-4.
Luster, A. D. (2001). "Antichemokine immunotherapy for allergic diseases." Curr Opin Allergy Clin Immunol 1(6): 561-7.
Chemokines have emerged as critical regulators of leukocyte function and as such represent attractive new targets for the therapy of allergic diseases. Recent studies have revealed important roles for the chemokine family in both the afferent and efferent limbs of the immune system, orchestrating and integrating innate and acquired immune responses. A subset of chemokines including eotaxin-1 (also called CCL11), eotaxin-2 (CCL24), eotaxin-3 (CCL26), MCP (monocyte chemoattractant protein)-3 (CCL7), MCP (monocyte chemoattractant protein)-4 (CCL13), TARC (thymus- and activation-regulated chemokine) (CCL17), and MDC (macrophage-derived chemokine) (CCL22) are highly expressed in allergic inflammation and are regulated by T helper type 2 cytokines. Receptors for these chemokines, including CCR3 (CC chemokine receptor 3), CCR4 (CC chemokine receptor 4) and CCR8 (CC chemokine receptor 8) are expressed on key leukocytes associated with allergic inflammation, such as T helper type 2 cells, eosinophils, mast cells and basophils, establishing a subset of chemokine/chemokine receptors potentially important in allergic inflammation. Recent data using inhibitory antibodies and chemokine antagonists support the concept that interfering with this subset of chemokines and their receptors represents a new approach to allergy immunotherapy.
Lilly, C. M., H. Nakamura, et al. (2001). "Eotaxin expression after segmental allergen challenge in subjects with atopic asthma." Am J Respir Crit Care Med 163(7): 1669-75.
Expression of pulmonary eotaxin protein and mRNA was determined in six subjects with atopic asthma and five nonatopic normal subjects. Levels of eotaxin expression and eosinophil mobilization were compared before and after segmental allergen challenge in subjects with atopic asthma. In the absence of allergen challenge, we found significantly higher levels of eotaxin in the bronchoalveolar lavage (BAL) fluid of subjects with asthma than in that of normal subjects (25 +/- 3 versus 15 +/- 2 pg/ml, p < 0.05). BAL eotaxin levels increased after segmental allergen challenge in all six subjects with atopic asthma tested, with a mean increase from 22 +/- 4 to 53 +/- 10 pg/ml (p = 0.013). Segmental allergen challenge was associated with a significant increase in the percentage of BAL macrophages and eosinophils that were immunopositive for eotaxin. Eotaxin mRNA was detectable by northern analysis in BAL cells exclusively from allergen-challenged segments. Allergen- induced increases in eotaxin levels were strongly associated with increases in BAL eosinophil recovery (r(2) = 0.88, p = 0.0036). Segmental allergen challenge also increased eotaxin expression in airway epithelial and endothelial cells obtained by endobronchial biopsy. These findings demonstrate, for the first time, that the airways of subjects with allergic asthma respond to allergen by increasing eotaxin expression. The tissue loci of eotaxin expression, the levels of eotaxin recovered in BAL fluid, and the association of eotaxin levels with eosinophil mobilization suggest either that eotaxin plays a mechanistic role in allergen-induced airway eosinophilia or that it serves as a biomarker for the causal mechanisms.
Klein, R. S., J. B. Rubin, et al. (2001). "SDF-1 alpha induces chemotaxis and enhances Sonic hedgehog-induced proliferation of cerebellar granule cells." Development 128(11): 1971-81.
The chemokine SDF-1 alpha (CXC12) and its receptor CXCR4 have been shown to play a role in the development of normal cerebellar cytoarchitecture. We report here that SDF-1 alpha both induces chemotactic responses in granule precursor cells and enhances granule cell proliferative responses to Sonic hedgehog. Chemotactic and proliferative responses to SDF-1 alpha are greater in granule cells obtained from cerebella of animals in the first postnatal week, coinciding with the observed in vivo peak in cerebellar CXCR4 expression. SDF-1 alpha activation of neuronal CXCR4 differs from activation of CXCR4 in leukocytes in that SDF-1 alpha-induced calcium flux is activity dependent, requiring predepolarization with KCl or pretreatment with glutamate. However, as is the case in leukocytes, neuronal responses to SDF-1 alpha are all abolished by pretreatment of granule cells with pertussis toxin, suggesting they occur through G(alpha i) activation. In conclusion, SDF-1 alpha plays a role in two important processes of granule cell maturation - proliferation and migration - assisting in the achievement of appropriate cell number and position in the cerebellar cortex.
Hancock, W. W., W. Gao, et al. (2001). "Donor-derived IP-10 initiates development of acute allograft rejection." J Exp Med 193(8): 975-80.
An allograft is often considered an immunologically inert playing field on which host leukocytes assemble and wreak havoc. However, we demonstrate that graft-specific physiologic responses to early injury initiate and promulgate destruction of vascularized grafts. Serial analysis of allografts showed that intragraft expression of the three chemokine ligands for the CXC chemo-kine receptor CXCR3 was induced in the order of interferon (IFN)-gamma-inducible protein of 10 kD (IP-10, or CXCL10), IFN-inducible T cell alpha-chemoattractant (I-TAC; CXCL11), and then monokine induced by IFN-gamma (Mig, CXCL9). Initial IP-10 production was localized to endothelial cells, and only IP-10 was induced by isografting. Anti-IP-10 monoclonal antibodies prolonged allograft survival, but surprisingly, IP-10-deficient (IP-10(-/-)) mice acutely rejected allografts. However, though allografts from IP-10(+/+) mice were rejected by day 7, hearts from IP-10(-/-) mice survived long term. Compared with IP-10(+/+) donors, use of IP-10(-/-) donors reduced intragraft expression of cytokines, chemokines and their receptors, and associated leukocyte infiltration and graft injury. Hence, tissue-specific generation of a single chemokine in response to initial ischemia/reperfusion can initiate progressive graft infiltration and amplification of multiple effector pathways, and targeting of this proximal chemokine can prevent acute rejection. These data emphasize the pivotal role of donor-derived IP-10 in initiating alloresponses, with implications for tissue engineering to decrease immunogenicity, and demonstrate that chemokine redundancy may not be operative in vivo.
Geiben-Lynn, R., M. Kursar, et al. (2001). "Noncytolytic inhibition of X4 virus by bulk CD8(+) cells from human immunodeficiency virus type 1 (HIV-1)-infected persons and HIV-1-specific cytotoxic T lymphocytes is not mediated by beta-chemokines." J Virol 75(17): 8306-16.
Human immunodeficiency virus (HIV)-specific cytotoxic T lymphocytes (CTL) mediate immunologic selection pressure by both cytolytic and noncytolytic mechanisms. Non cytolytic mechanisms include the release of beta-chemokines blocking entry of R5 HIV-1 strains. In addition, CD8(+) cells inhibit X4 virus isolates via release of as yet poorly characterized soluble factors. To further characterize these factors, we performed detailed analysis of CTL as well as bulk CD8(+) T lymphocytes from six HIV-1-infected individuals and from six HIV-1-seronegative individuals. Kinetic studies revealed that secreted suppressive activities of HIV-1-specific CTL and bulk CD8(+) T lymphocytes from all HIV-1-infected persons are significantly higher than that of supernatants from seronegative controls. The suppressive activity could be blocked by monensin and brefeldin A, was heat labile, and appeared in a pattern different from that of secretion of chemokines (MDC, I-309, MIP-1alpha, MIP-1beta, and RANTES), cytokines (gamma interferon, tumor necrosis factor alpha, and granulocyte-macrophage colony-stimulating factor), and interleukins (interleukin-13 and interleukin-16). This suppression activity was characterized by molecular size exclusion centrifugation and involves a suppressive activity of >50 kDa which could be bound to heparin and a nonbinding inhibitory activity of <50 kDa. Our data provide a functional link between CD8(+) cells and CTL in the noncytolytic inhibition of HIV-1 and suggest that suppression of X4 virus is mediated through proteins. The sizes of the proteins, their affinity for heparin, and the pattern of release indicate that these molecules are not chemokines.
Fife, B. T., K. J. Kennedy, et al. (2001). "CXCL10 (IFN-gamma-inducible protein-10) control of encephalitogenic CD4+ T cell accumulation in the central nervous system during experimental autoimmune encephalomyelitis." J Immunol 166(12): 7617-24.
Experimental autoimmune encephalomyelitis (EAE) is a CD4(+) Th1-mediated demyelinating disease of the CNS that serves as a model for multiple sclerosis. A critical event in the pathogenesis of EAE is the entry of both Ag-specific and Ag-nonspecific T lymphocytes into the CNS. In the present report, we investigated the role of the CXC chemokine CXCL10 (IFN-gamma-inducible protein-10) in the pathogenesis of EAE. Production of CXCL10 in the CNS correlated with the development of clinical disease. Administration of anti-CXCL10 decreased clinical and histological disease incidence, severity, as well as infiltration of mononuclear cells into the CNS. Anti-CXCL10 specifically decreased the accumulation of encephalitogenic PLP(139-151) Ag-specific CD4+ T cells in the CNS compared with control-treated animals. Anti-CXCL10 administration did not affect the activation of encephalitogenic T cells as measured by Ag-specific proliferation and the ability to adoptively transfer EAE. These results demonstrate an important role for the CXC chemokine CXCL10 in the recruitment and accumulation of inflammatory mononuclear cells during the pathogenesis of EAE.
Abi-Younes, S., M. Si-Tahar, et al. (2001). "The CC chemokines MDC and TARC induce platelet activation via CCR4." Thromb Res 101(4): 279-89.
While chemokines have received considerable attention for their role in leukocyte chemotaxis, their effects on platelets have not been well described. We found that two CC chemokine receptor 4 (CCR4) ligands, macrophage-derived chemokine (MDC) and thymus and activation-regulated chemokine (TARC) induce concentration-dependent platelet aggregation and calcium flux. Flow cytometric analysis revealed the expression of CCR4 on platelets and a monoclonal antibody (mAb) to CCR4 inhibited MDC- and TARC-induced platelet aggregation, confirming that this effect is mediated through their common receptor CCR4. MDC fully desensitized TARC-induced calcium mobilization in platelets, while TARC was unable to completely desensitize a subsequent MDC response, which is similar to observations made in Th2 CD4(+) lymphocytes and CCR4-transfected cells. Aspirin (ASA) treatment of platelets allowed reversible primary aggregation but inhibited irreversible complete aggregation, suggesting that MDC- and TARC-induced full platelet aggregation is dependent on cyclooxygenase metabolites of arachidonic acid. MDC and TARC were unable to induce platelet aggregation and platelet secretion in washed human platelets, even though they induced a calcium flux, suggesting that plasma components are required for MDC- and TARC-induced platelet aggregation. Since Th2-type cytokines induce the release of MDC and TARC from cells and the expression of these chemokines is increased in Th2-type inflammation, we hypothesize that MDC and TARC may play a role in platelet activation seen in Th2 diseases, such as asthma and atopic dermatitis.
Tager, A. M., J. H. Dufour, et al. (2000). "BLTR mediates leukotriene B(4)-induced chemotaxis and adhesion and plays a dominant role in eosinophil accumulation in a murine model of peritonitis." J Exp Med 192(3): 439-46.
Leukotriene B(4) (LTB(4)) is a potent chemoattractant active on multiple leukocytes, including neutrophils, macrophages, and eosinophils, and is implicated in the pathogenesis of a variety of inflammatory processes. A seven transmembrane-spanning, G protein-coupled receptor, called BLTR (LTB(4) receptor), has recently been identified as an LTB(4) receptor. To determine if BLTR is the sole receptor mediating LTB(4)-induced leukocyte activation and to determine the role of LTB(4) and BLTR in regulating leukocyte function in inflammation in vivo, we generated a BLTR-deficient mouse by targeted gene disruption. This mouse reveals that BLTR alone is responsible for LTB(4)-mediated leukocyte calcium flux, chemotaxis, and firm adhesion to endothelium in vivo. Furthermore, despite the apparent functional redundancy with other chemoattractant-receptor pairs in vitro, LTB(4) and BLTR play an important role in the recruitment and/or retention of leukocytes, particularly eosinophils, to the inflamed peritoneum in vivo. These studies demonstrate that BLTR is the key receptor that mediates LTB(4)-induced leukocyte activation and establishes a model to decipher the functional roles of BLTR and LTB(4) in vivo.
Poznansky, M. C., I. T. Olszak, et al. (2000). "Active movement of T cells away from a chemokine." Nat Med 6(5): 543-8.
Movement towards or away from a given stimulus guides the directional migration of prokaryotes, simple eukaryotes and neurons. As bi-directional cues may influence entry and exit of immune effector cells from tissue sites, we evaluated the migratory responses of T-cell subsets to varying concentrations of the chemokine stromal cell derived factor-1 (SDF-1). There was selective repulsion of subpopulations of T cells at high concentrations of recombinant SDF-1 or naturally occurring bone marrow-derived SDF-1, which could be inhibited by pertussis toxin and antibody against the chemokine receptor CXCR4. Distinct sensitivity profiles to genistein, herbimycin and 8-Br-cAMP biochemically distinguished movement of cells towards or away from an SDF-1 gradient. In vivo, antigen-induced T-cell recruitment into the peritoneal cavity was reversed by high but not low concentrations of SDF-1. The phenomenon of movement away from a chemokine represents a previously unknown mechanism regulating the localization of mature T cells. It adds to the functional repertoire of chemokines that may participate in immune physiology and may be applied therapeutically to alter the immune response.
Pavlovich, C. P., B. M. Kraling, et al. (2000). "BCG-induced urinary cytokines inhibit microvascular endothelial cell proliferation." J Urol 163(6): 2014-21.
PURPOSE: Angiogenesis is thought to depend on a net balance of molecules that inhibit or stimulate microvascular endothelial cells. A variety of molecules that affect angiogenesis are induced locally by the administration of intravesical bacille Calmette-Guerin (BCG) for superficial bladder cancer. We sought to determine whether BCG-induced urinary cytokines alter the effects of patient urine on assays of angiogenic activity. MATERIALS AND METHODS: Patients undergoing BCG treatment provided urine samples before and at peak cytokine production times after BCG instillation. Fifty-four urine samples from 8 patients were analyzed by ELISA for a panel of molecules known to affect angiogenesis, and tested for angiogenic activity in human dermal microvascular endothelial cell (HDMEC) proliferation and migration assays. To assess the role of specific BCG-induced cytokines, urinary HDMEC proliferation assays were repeated in the presence of neutralizing antibodies to tumor necrosis factor-alpha (TNF-alpha), interferon-inducible protein-10 (IP-10), and/or interferon-gamma (IFN-gamma). RESULTS: Urinary IFN-gamma, IP-10, TNF-alpha, and vascular endothelial growth factor (VEGF) were induced to nanogram/ml amounts by BCG treatment. While pre-BCG treatment urine samples minimally stimulated microvascular endothelial cell proliferation (+ 9%), post-BCG treatment urine became progressively inhibitory to endothelial cells (to -85%, p = 0.005) during weekly treatment courses. Neutralizing antibodies to TNF-alpha or to IP-10, either alone or in combination, greatly reduced this inhibitory effect. CONCLUSIONS: Intravesical BCG induces a cytokine-rich urinary microenvironment that is inhibitory to human endothelial cells. Urinary cytokine profiles and assays of angiogenic inhibition may provide prognostically important information regarding BCG treatment outcomes.
Marx, N., F. Mach, et al. (2000). "Peroxisome proliferator-activated receptor-gamma activators inhibit IFN-gamma-induced expression of the T cell-active CXC chemokines IP-10, Mig, and I-TAC in human endothelial cells." J Immunol 164(12): 6503-8.
Peroxisome proliferator-activated receptor-gamma (PPARgamma), a member of the nuclear hormone receptor superfamily originally shown to play an important role in adipocyte differentiation and glucose homeostasis, is now known to regulate inflammatory responses. Given the importance of endothelial cell (EC)-derived chemokines in regulating leukocyte function and trafficking, we studied the effects of PPARgamma ligands on the expression of chemokines induced in ECs by the Th1 cytokine IFN-gamma. Treatment of ECs with PPARgamma activators significantly inhibited IFN-gamma-induced mRNA and protein expression of the CXC chemokines IFN-inducible protein of 10 kDa (IP-10), monokine induced by IFN-gamma (Mig), and IFN-inducible T-cell alpha-chemoattractant (I-TAC), whereas expression of the CC chemokine monocyte chemoattractant protein-1 was not altered. PPARgamma activators decreased IFN-inducible protein of 10 kDa promoter activity and inhibited protein binding to the two NF-kappaB sites but not to the IFN-stimulated response element ISRE site. Furthermore, PPARgamma ligands inhibited the release of chemotactic activity for CXC chemokine receptor 3 (CXCR3)-transfected lymphocytes from IFN-gamma-stimulated ECs. These data suggest that anti-diabetic PPARgamma activators might attenuate the recruitment of activated T cells at sites of Th1-mediated inflammation.
MacLean, J. A., G. T. De Sanctis, et al. (2000). "CC chemokine receptor-2 is not essential for the development of antigen-induced pulmonary eosinophilia and airway hyperresponsiveness." J Immunol 165(11): 6568-75.
Monocyte chemoattractant proteins-1 and -5 have been implicated as important mediators of allergic pulmonary inflammation in murine models of asthma. The only identified receptor for these two chemokines to date is the CCR2. To study the role of CCR2 in a murine model of Ag-induced asthma, we compared the pathologic and physiological responses of CCR2(-/-) mice with those of wild-type (WT) littermates following immunization and challenge with OVA. OVA-immunized/OVA-challenged (OVA/OVA) WT and CCR2(-/-) mice developed significant increases in total cells recovered by bronchoalveolar lavage (BAL) compared with their respective OVA-immunized/PBS-challenged (OVA/PBS) control groups. There were no significant differences in BAL cell counts and differentials (i.e., macrophages, PMNs, lymphocytes, and eosinophils) between OVA/OVA WT and CCR2(-/-) mice. Serologic evaluation revealed no significant difference in total IgE and OVA-specific IgE between OVA/OVA WT mice and CCR2(-/-) mice. Lung mRNA expression and BAL cytokine protein levels of IL-4, IL-5, and IFN-gamma were also similar in WT and CCR2(-/-) mice. Finally, OVA/OVA CCR2(-/-) mice developed increased airway hyper-responsiveness to a degree similar to that in WT mice. We conclude that following repeated airway challenges with Ag in sensitized mice, the development of Th2 responses (elevated IgE, pulmonary eosinophilia, and lung cytokine levels of IL-4 and IL5) and the development of airway hyper-responsiveness are not diminished by a deficiency in CCR2.
Luscinskas, F. W., R. E. Gerszten, et al. (2000). "C-C and C-X-C chemokines trigger firm adhesion of monocytes to vascular endothelium under flow conditions." Ann N Y Acad Sci 902: 288-93.
In summary, our findings indicate that specific chemokines that are elaborated by endothelial cells after cytokine or endotoxin activation can play an essential role in monocyte recruitment beyond their chemoattractant activities. We show that this action is to translate initial monocyte tethering into firm adhesion via rapid leukocyte integrin activation. The in vitro model presented here provides a sensitive system for investigating the modulating ability of chemokines and reveals an important biological effect that is not predicted by results in simpler in vitro assays, such as measurement of calcium transients or chemotaxis. The surprising finding that the C-X-C chemokine IL-8 can trigger monocyte firm adhesion to vascular endothelium suggests a potential role for this chemokine in monocyte recruitment and underscores the biological complexity of the chemokine family.
Lamkhioued, B., E. A. Garcia-Zepeda, et al. (2000). "Monocyte chemoattractant protein (MCP)-4 expression in the airways of patients with asthma. Induction in epithelial cells and mononuclear cells by proinflammatory cytokines." Am J Respir Crit Care Med 162(2 Pt 1): 723-32.
Chemokines are chemotactic cytokines that play an important role in recruiting leukocytes in allergic inflammation. Monocyte chemoacctractant protein (MCP)-4 is a CC chemokine with potent chemotactic activities for eosinophils, monocytes, T lymphocytes, and basophils and therefore represents a good candidate to participate in allergic reactions. To determine if MCP-4 plays a role in asthma, we have investigated the expression of MCP-4 messenger RNA (mRNA) and protein in the airways of patients with asthma and normal control subjects by in situ hybridization and immunohistochemistry. We found that MCP-4 mRNA and protein was significantly upregulated in the epithelium and submucosa of bronchial biopsies and in the bronchoalveolar lavage (BAL) cells of patients with asthma compared with normal control subjects (p < 0. 01). In addition, MCP-4 protein was significantly elevated in the BAL fluid of patients with atopic asthma when compared with normal control subjects (p < 0.01) and there was a significant correlation between MCP-4, eotaxin, and eosinophils. In support of our in situ findings demonstrating MCP-4 expression in epithelial cells and mononuclear cells in vivo, we have found that MCP-4 expression can be induced in these cells in vitro by tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta). Interferon-gamma (IFN-gamma) acted synergistically with TNF-alpha and IL-1beta in the induction of mRNA MCP-4 mRNA expression in A549 cells, whereas the glucocorticoid dexamethasone diminished the cytokine-induced expression of MCP-4. Our findings demonstrate that MCP-4 is upregulated in the airways of patients with asthma and suggest that MCP-4 plays a role in the recruitment of eosinophils into the airways of patients with asthma.
Khan, I. A., J. A. MacLean, et al. (2000). "IP-10 is critical for effector T cell trafficking and host survival in Toxoplasma gondii infection." Immunity 12(5): 483-94.
The generation of an adaptive immune response against intracellular pathogens requires the recruitment of effector T cells to sites of infection. Here we show that the chemokine IP-10, a specific chemoattractant for activated T cells, controls this process in mice naturally infected with Toxoplasma gondii. Neutralization of IP-10 in infected mice inhibited the massive influx of T cells into tissues and impaired antigen-specific T cell effector functions. This resulted in >1000-fold increase in tissue parasite burden and a marked increase in mortality compared to control antibody-treated mice. These observations suggest that IP-10 may play a broader role in the localization and function of effector T cells at sites of Th1 inflammation.
Jedrzkiewicz, S., H. Nakamura, et al. (2000). "IL-1beta induces eotaxin gene transcription in A549 airway epithelial cells through NF-kappaB." Am J Physiol Lung Cell Mol Physiol 279(6): L1058-65.
Eotaxin is an asthma-related C-C chemokine that is produced in response to interleukin-1beta (IL-1beta). We detected an increase in newly transcribed eotaxin mRNA in IL-1beta-stimulated airway epithelial cells. Transient transfection assays using promoter-reporter constructs identified a region as essential for IL-1beta-induced increases in eotaxin transcription. Using site-directed mutagenesis, we found that a nuclear factor-kappaB (NF-kappaB) site located 46 bp upstream from the transcriptional start site was both necessary and sufficient for IL-1beta induction of reporter construct activity. Electrophoretic mobility shift assay demonstrated that IL-1beta-stimulated airway epithelial cells produced p50 and p65 protein that bound this site in a sequence-specific manner. The functional importance of the NF-kappaB site was demonstrated by coexpression experiments in which increasing doses of p65 expression vector were directly associated with reporter activity exclusively in constructs with an intact NF-kappaB site (r(2) = 0.97, P = 0.002). Moreover, IL-1beta-induced increases in eotaxin mRNA expression are inhibited by inhibitors of NF-kappaB. Our findings implicate NF-kappaB and its binding sequence in IL-1beta-induced transcriptional activation of the eotaxin gene.
Izikson, L., R. S. Klein, et al. (2000). "Resistance to experimental autoimmune encephalomyelitis in mice lacking the CC chemokine receptor (CCR)2." J Exp Med 192(7): 1075-80.
Monocyte recruitment to the central nervous system (CNS) is a necessary step in the development of pathologic inflammatory lesions in experimental autoimmune encephalomyelitis (EAE), a murine model of multiple sclerosis. Monocyte chemoattractant protein (MCP)-1, a potent agonist for directed monocyte migration, has been implicated in the pathogenesis of EAE. Here we report that deficiency in CC chemokine receptor (CCR)2, the receptor for MCP-1, confers resistance to EAE induced with a peptide derived from myelin oligodendrocyte glycoprotein peptide 35-55 (MOGp35-55). CCR2(-/)- mice immunized with MOGp35-55 failed to develop mononuclear cell inflammatory infiltrates in the CNS and failed to increase CNS levels of the chemokines RANTES (regulated on activation, normal T cell expressed and secreted), MCP-1, and interferon (IFN)-inducible protein 10 (IP-10) as well the chemokine receptors CCR1, CCR2, and CCR5. Additionally, T cells from CCR2(-/)- immunized mice showed decreased antigen-induced proliferation and production of IFN-gamma compared with wild-type immunized controls, suggesting that CCR2 enhances the T helper cell type 1 immune response in EAE. These data indicate that CCR2 plays a necessary and nonredundant role in the pathogenesis of EAE.
Gerszten, R. E., F. Mach, et al. (2000). "Chemokines, leukocytes, and atherosclerosis." J Lab Clin Med 136(2): 87-92.
Abi-Younes, S., A. Sauty, et al. (2000). "The stromal cell-derived factor-1 chemokine is a potent platelet agonist highly expressed in atherosclerotic plaques." Circ Res 86(2): 131-8.
Chemokines are chemotactic cytokines that activate and direct the migration of leukocytes. However, their role in modulating platelet function has not been shown. We studied the direct effect of chemokines on human platelets and found that of the 16 tested only stromal cell-derived factor (SDF)-1 induced platelet aggregation, accompanied by a rise in intracellular calcium. Platelets expressed the SDF-1 receptor, CXCR4, and an antibody to CXCR4 and pertussis toxin inhibited SDF-1-induced platelet aggregation, confirming that this effect is mediated through CXCR4, a Galphai-coupled receptor. SDF-1-induced platelet aggregation was also inhibited by wortmannin, LY294002, and genistein, suggesting that phosphatidylinositol 3-kinase and tyrosine kinase are likely involved in SDF-1-induced platelet aggregation. Because chemokines are produced from multiple vascular cells and atherosclerotic vessels are prone to develop platelet-rich thrombi, we examined the expression of SDF-1 in human atheroma. SDF-1 protein was highly expressed in smooth muscle cells, endothelial cells, and macrophages in human atherosclerotic plaques but not in normal vessels. Our studies demonstrate a direct effect of a chemokine in inducing platelet activation and suggest a role for SDF-1 in the pathogenesis of atherosclerosis and thrombo-occlusive diseases.
Yang, O. O., S. L. Swanberg, et al. (1999). "Enhanced inhibition of human immunodeficiency virus type 1 by Met-stromal-derived factor 1beta correlates with down-modulation of CXCR4." J Virol 73(6): 4582-9.
CXCR4 is a chemokine receptor used by some strains of HIV-1 as an entry coreceptor in association with cell surface CD4 on human cells. In human immunodeficiency virus type 1 (HIV-1)-infected individuals, the appearance of viral isolates with a tropism for CXCR4 (T tropic) has been correlated with late disease progression. The presumed natural ligands for CXCR4 are SDF-1alpha and SDF-1beta, which are proposed to play a role in blocking T-tropic HIV-1 cell entry. Here, we demonstrate that addition of an N-terminal methionine residue to SDF-1beta (Met-SDF-1beta) results in a dramatically enhanced functional activity compared to that of native SDF-1beta. Equivalent concentrations of Met-SDF-1beta are markedly more inhibitory for T-tropic HIV-1 replication than SDF-1beta. A comparison of the biological activities of these two forms of SDF-1beta reveals that Met-SDF-1beta induces a more pronounced intracellular calcium flux yet binds with slightly lower affinity to CXCR4 than SDF-1beta. Down-modulation of CXCR4 is similar after exposure of cells to either chemokine form for 2 h. However, after a 48-h incubation, the surface expression of CXCR4 is much lower for cells treated with Met-SDF-1beta. The enhanced blocking of T-tropic HIV-1 by Met-SDF-1beta appears to be related to prolonged CXCR4 down-modulation.
Tager, A. M., A. D. Luster, et al. (1999). "Accessory cells with immunophenotypic and functional features of monocyte-derived dendritic cells are recruited to the lung during pulmonary inflammation." J Leukoc Biol 66(6): 901-8.
Pulmonary macrophages (Mphi) increase in tissue and bronchoalveolar lavage (BAL) fluid during inflammation caused by bleomycin (BLM). This study demonstrates that increasing numbers of exudate Mphi in BLM lung injury exhibit dendritic cell (DC) features. After the intratracheal administration of BLM (0.075 U), adherent mononuclear cells from the bronchoalveolar lavage fluid (BAMC) of C57BL/6 mice were characterized for morphology, immunophenotype, and accessory cell activities. At day 7 post-BLM, 48% of CD11b+ BAMC displayed features of DC differentiation, as judged by dendritic morphology, expression of class II MHC, 33D1, Factor XIIIa, CD80, and CD86 antigens, and the ability to support a primary allogeneic lymphocyte response (MLR). After BLM treatment, CD11b+ peripheral blood monocytes also showed increased expression of 33D1, Factor XIIIa, CD86, and the ability to stimulate an MLR. We conclude that inflammatory DC with immunophenotypic features of monocyte-derived DC increase in the peripheral blood and lung after an inflammatory stimulus.
Shen, H., T. Cheng, et al. (1999). "Intrinsic human immunodeficiency virus type 1 resistance of hematopoietic stem cells despite coreceptor expression." J Virol 73(1): 728-37.
Interactions of human immunodeficiency virus type 1 (HIV-1) with hematopoietic stem cells may define restrictions on immune reconstitution following effective antiretroviral therapy and affect stem cell gene therapy strategies for AIDS. In the present study, we demonstrated mRNA and cell surface expression of HIV-1 receptors CD4 and the chemokine receptors CCR-5 and CXCR-4 in fractionated cells representing multiple stages of hematopoietic development. Chemokine receptor function was documented in subsets of cells by calcium flux in response to a cognate ligand. Productive infection by HIV-1 via these receptors was observed with the notable exception of stem cells, in which case the presence of CD4, CXCR-4, and CCR-5, as documented by single-cell analysis for expression and function, was insufficient for infection. Neither productive infection, transgene expression, nor virus entry was detectable following exposure of stem cells to either wild-type HIV-1 or lentivirus constructs pseudotyped in HIV-1 envelopes of macrophage-tropic, T-cell-tropic, or dualtropic specificity. Successful entry into stem cells of a vesicular stomatitis virus G protein-pseudotyped HIV-1 construct demonstrated that the resistance to HIV-1 was mediated at the level of virus-cell membrane fusion and entry. These data define the hematopoietic stem cell as a sanctuary cell which is resistant to HIV-1 infection by a mechanism independent of receptor and coreceptor expression that suggests a novel means of cellular protection from HIV-1.
Sauty, A., M. Dziejman, et al. (1999). "The T cell-specific CXC chemokines IP-10, Mig, and I-TAC are expressed by activated human bronchial epithelial cells." J Immunol 162(6): 3549-58.
Recruitment of activated T cells to mucosal surfaces, such as the airway epithelium, is important in host defense and for the development of inflammatory diseases at these sites. We therefore asked whether the CXC chemokines IFN-induced protein of 10 kDa (IP-10), monokine induced by IFN-gamma (Mig), and IFN-inducible T-cell alpha-chemoattractant (I-TAC), which specifically chemoattract activated T cells by signaling through the chemokine receptor CXCR3, were inducible in respiratory epithelial cells. The effects of proinflammatory cytokines, including IFN-gamma (Th1-type cytokine), Th2-type cytokines (IL-4, IL-10, and IL-13), and dexamethasone were studied in normal human bronchial epithelial cells (NHBEC) and in two human respiratory epithelial cell lines, A549 and BEAS-2B. We found that IFN-gamma, but not TNF-alpha or IL-1 beta, strongly induced IP-10, Mig, and I-TAC mRNA accumulation mainly in NHBEC and that TNF-alpha and IL-1 beta synergized with IFN-gamma induction in all three cell types. High levels of IP-10 protein (> 800 ng/ml) were detected in supernatants of IFN-gamma/TNF-alpha-stimulated NHBEC. Neither dexamethasone nor Th2 cytokines modulated IP-10, Mig, or I-TAC expression. Since IFN-gamma is up-regulated in tuberculosis (TB), using in situ hybridization we studied the expression of IP-10 in the airways of TB patients and found that IP-10 mRNA was expressed in the bronchial epithelium. In addition, IP-10-positive cells obtained by bronchoalveolar lavage were significantly increased in TB patients compared with normal controls. These results show that activated bronchial epithelium is an important source of IP-10, Mig, and I-TAC, which may, in pulmonary diseases such as TB (in which IFN-gamma is highly expressed) play an important role in the recruitment of activated T cells.
Nakamura, H., S. T. Weiss, et al. (1999). "Eotaxin and impaired lung function in asthma." Am J Respir Crit Care Med 160(6): 1952-6.
We performed an association study of plasma eotaxin levels, eosinophil counts, total IgE levels, asthma diagnosis, and lung function in an ethnically diverse and geographically dispersed population. We studied 515 asthmatic and 519 normal subjects, none of whom was taking inhaled or oral corticosteroids. Logistic regression analysis demonstrated a direct relationship between asthma diagnosis and eotaxin levels (p < 0.0001). The odds of an asthma diagnosis increased with eotaxin quartile, with the highest quartile having an odds ratio of 5.4 (95% CI 3.2 to 9.2, p < 0.001) compared with the lowest eotaxin quartile. Eotaxin levels were inversely related to lung function (p < 0.001), with the mean percent predicted FEV(1) in the highest eotaxin quartile being 13.5 percentage points (SEM 2.1, p < 0.001) less than that in the lowest quartile. Plasma eotaxin levels were associated with asthma and inversely related to lung function independent of age, race, sex, or smoking status. When combined with eosinophil counts and IgE levels, eotaxin levels contributed to the odds of an asthma diagnosis and of impaired lung function. Our results are the first to associate eotaxin levels with asthma diagnosis and compromised lung function in a large geographically and ethnically diverse population.
MacLean, J. A., A. Sauty, et al. (1999). "Antigen-induced airway hyperresponsiveness, pulmonary eosinophilia, and chemokine expression in B cell-deficient mice." Am J Respir Cell Mol Biol 20(3): 379-87.
Murine models of allergen-induced pulmonary inflammation share many features with human asthma, including the development of antigen-induced pulmonary eosinophilia, airway hyperresponsiveness, antigen-specific cellular and antibody responses, the elaboration of Th2 cytokines (interleukin [IL]-4 and IL-5), and the expression of chemokines with activity for eosinophils. We examined the role of B cells and antigen-specific antibody responses in such a model by studying the histopathologic and physiologic responses of B cell-deficient mice compared with wild-type controls, following systemic immunization and airway challenge with ovalbumin (OVA). Both OVA-challenged wild-type and B cell-deficient mice developed (1) airway hyperresponsiveness, (2) pulmonary inflammation with activated T cells and eosinophils, (3) IL-4 and IL-5 secretion into the airway lumen, and (4) increased expression of the eosinophil active chemokines eotaxin and monocyte chemotactic protein-3. There were no significant differences in either the pathologic or physiologic responses in the B cell-deficient mice compared with wild-type mice. These data indicate that B cells and antigen-specific antibodies are not required for the development of airway hyperresponsiveness, eosinophilic pulmonary inflammation, and chemokine expression in sensitized mice following aerosol challenge with antigen.
Mach, F., A. Sauty, et al. (1999). "Differential expression of three T lymphocyte-activating CXC chemokines by human atheroma-associated cells." J Clin Invest 104(8): 1041-50.
Activated T lymphocytes accumulate early in atheroma formation and persist at sites of lesion growth and rupture, suggesting that they may play an important role in the pathogenesis of atherosclerosis. Moreover, atherosclerotic lesions contain the Th1-type cytokine IFN-gamma, a potentiator of atherosclerosis. The present study demonstrates the differential expression of the 3 IFN-gamma-inducible CXC chemokines--IFN-inducible protein 10 (IP-10), monokine induced by IFN-gamma (Mig), and IFN-inducible T-cell alpha chemoattractant (I-TAC)--by atheroma-associated cells, as well as the expression of their receptor, CXCR3, by all T lymphocytes within human atherosclerotic lesions in situ. Atheroma-associated endothelial cells (ECs), smooth muscle cells (SMCs), and macrophages (MO) all expressed IP-10, whereas Mig and I-TAC were mainly expressed in ECs and MO, as detected by double immunofluorescence staining. ECs of microvessels within lesions also expressed abundant I-TAC. In vitro experiments supported these results and showed that IL-1beta, TNF-alpha, and CD40 ligand potentiated IP-10 expression from IFN-gamma-stimulated ECs. In addition, nitric oxide (NO) treatment decreased IFN-gamma induction of IP-10. Our findings suggest that the differential expression of IP-10, Mig, and I-TAC by atheroma-associated cells plays a role in the recruitment and retention of activated T lymphocytes observed within vascular wall lesions during atherogenesis.
Lu, B., A. Humbles, et al. (1999). "Structure and function of the murine chemokine receptor CXCR3." Eur J Immunol 29(11): 3804-12.
The gene encoding the murine homologue of human CXCR3 exists in a single copy consisting of two exons with an intron interrupting the coding sequence between nucleotides 10 and 11. The deduced amino acid sequence is 86% identical to the predicted human sequence. Murine CXCR3 mRNA is detectable in bone marrow cells cultured in the presence of IL-2 but not unstimulated cells. It is also detectable at low abundance in normal mouse spleen, lymph node, mammary gland, and thymus. Transfection of murine CXCR3 in murine pre-B lymphocyte line (CXCR3++/L1.2) conferred binding of the ligands IP10, ITAC and Mig with K(D)'s of 1.35 +/- 0.56, 1.41 +/- 0.20, and 11.65 +/- 0.90 nM, respectively. Lower affinity binding was observed for several beta or CC chemokines (eotaxin, MCP-3, MIP3alpha and SLC/6Ckine/Exodus 2). ITAC, IP10 and Mig induced chemotaxis with an order of potency ITAC > IP10 = Mig. The chemokines also increased intracellular calcium concentration and were variably desensitized to repeated agonist stimulation. The hierarchy for cross- desensitization was ITAC > Mig > IP10. Thus, while Mig, ITAC and IP10 all act on the same receptor for binding and agonist stimulation, they may interact with different receptor conformational isoforms to produce divergent responses.
Klein, R. S., K. C. Williams, et al. (1999). "Chemokine receptor expression and signaling in macaque and human fetal neurons and astrocytes: implications for the neuropathogenesis of AIDS." J Immunol 163(3): 1636-46.
Chemokines are believed to play a role in the neuropathogenesis of AIDS through their recruitment of neurotoxin-secreting, virally infected leukocytes into the CNS. Levels of chemokines are elevated in brains of patients and macaques with HIV/SIV-induced encephalitis. The chemokine receptors CCR3, CCR5, and CXCR4 are found on subpopulations of neurons in the cortex of human and macaque brain. We have developed an in vitro system using both macaque and human fetal neurons and astrocytes to further investigate the roles of these receptors in neuronal response to inflammation. Here we report the presence of functional HIV/SIV coreceptors CCR3, CCR5, and CXCR4 on fetal human and macaque neurons and CCR5 and CXCR4 on astrocytes immediately ex vivo and after several weeks in culture. Confocal imaging of immunostained neurons demonstrated different patterns of distribution for these receptors, which may have functional implications. Chemokine receptors were shown to respond to their appropriate chemokine ligands with increases in intracellular calcium that, in the case of neurons, required predepolarization with KCl. These responses were blocked by neutralizing chemokine receptor in mAbs. Pretreatment of neural cells with pertussis toxin abolished responses to stromal-derived factor-1alpha, macrophage inflammatory protein-1beta, and RANTES, indicating coupling of CCR5 and CXCR4 to a Gialpha protein, as in leukocytes. Cultured macaque neurons demonstrated calcium flux response to treatment with recombinant SIVmac239 envelope protein, suggesting a mechanism by which viral envelope could affect neuronal function in SIV infection. The presence of functional chemokine receptors on neurons and astrocytes suggests that chemokines could serve to link inflammatory and neuronal responses.
Ghaffar, O., Q. Hamid, et al. (1999). "Constitutive and cytokine-stimulated expression of eotaxin by human airway smooth muscle cells." Am J Respir Crit Care Med 159(6): 1933-42.
Airway eosinophilia is a prominent feature of asthma that is believed to be mediated in part through the expression of specific chemokines such as eotaxin, a potent eosinophil chemoattractant that is highly expressed by epithelial cells and inflammatory cells in asthmatic airways. Airway smooth muscle (ASM) has been identified as a potential source of cytokines and chemokines. The aim of the present study was to examine the capacity of human ASM to express eotaxin. We demonstrate that airway myocytes constitutively express eotaxin mRNA as detected by RT-PCR. Treatment of ASM for 24 h with different concentrations of TNF-alpha and IL-1beta alone or in combination enhanced the accumulation of eotaxin transcripts. Maximal mRNA expression of eotaxin was shown at 12 and 24 h following IL-1beta and TNF-alpha stimulation, respectively. The presence of immunoreactive eotaxin was demonstrated by immunocytochemistry, and constitutive and cytokine-stimulated release of eotaxin was confirmed in ASM culture supernatants by ELISA. Strong signals for eotaxin mRNA and immunoreactivity were observed in vivo in smooth muscle in asthmatic airways. In addition, chemotaxis assays demonstrated the presence of chemoattractant activity for eosinophils and PBMCs in ASM supernatants. The chemotactic responses of eosinophils were partly inhibited with antibodies directed against eotaxin or RANTES, and a combined blockade of both chemokines causes > 70% inhibition of eosinophil chemotaxis. The results of this study suggest that ASM may contribute to airway inflammation in asthma through the production and release of eotaxin.
Gerszten, R. E., E. A. Garcia-Zepeda, et al. (1999). "MCP-1 and IL-8 trigger firm adhesion of monocytes to vascular endothelium under flow conditions." Nature 398(6729): 718-23.
Monocytes contribute to the development of atherosclerotic lesions in mouse models. The chemoattractant proteins (chemokines), monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8), are found in human atheroma, and mice lacking receptors for these chemokines are less susceptible to atherosclerosis and have fewer monocytes in vascular lesions. Although MCP-1 has a powerful effect on monocytes, IL-8 is thought to act predominantly on neutrophils and it is unclear how it could recruit monocytes. Here we investigate the ability of chemokines to control the interaction of monocytes under flow conditions with vascular endothelium that has been transduced to express specific leukocyte-adherence receptors. We find that MCP-1 and IL-8 can each rapidly cause rolling monocytes to adhere firmly onto monolayers expressing E-selectin, whereas related chemokines do not. These effects do not correlate with either the induction of a calcium transient or chemotaxis. We conclude that chemokines are important modulators of monocyte-endothelial interactions under flow conditions. Moreover, our finding that IL-8 is a powerful trigger for firm adhesion of monocytes to vascular endothelium reveals an unexpected role for this chemokine in monocyte recruitment.
Wagner, L., O. O. Yang, et al. (1998). "Beta-chemokines are released from HIV-1-specific cytolytic T-cell granules complexed to proteoglycans." Nature 391(6670): 908-11.
CD8+ lymphocytes are believed to be important in host defence against the human immunodeficiency virus (HIV)-1, inhibiting HIV-1 replication through both cytolytic and non-cytolytic pathways. The cytolytic pathway involves calcium-dependent exocytosis of perforin and granzyme proteases, as well as Fas-mediated programmed cell death, whereas the noncytolytic pathway involves the release of chemokines that prevent viral entry. Using granzyme A as a marker of cytolytic granule proteins, and macrophage inflammatory protein (MIP)-1alpha and RANTES as markers of HIV-1 inhibitory chemokines, we show that these two very different mediators of viral inhibition are both localized in the cytolytic granules of HIV-1-specific CD8+ cytotoxic T lymphocytes (CTL). Following antigen-specific activation, these mediators are secreted together, facilitating both lysis of virion-producing cells and the inhibition of free virus. In addition, RANTES, MIP-1alpha and MIP-1beta are secreted by CTL as a macromolecular complex containing sulphated proteoglycans. This association appears to have a functional significance, because heparan sulphate facilitates RANTES inhibition of HIV-1 infection of monocytes.
van de Rijn, M., P. D. Mehlhop, et al. (1998). "A murine model of allergic rhinitis: studies on the role of IgE in pathogenesis and analysis of the eosinophil influx elicited by allergen and eotaxin." J Allergy Clin Immunol 102(1): 65-74.
BACKGROUND: Allergic rhinitis is a prevalent disease with significant morbidity. Studies of its pathophysiology in human subjects have been limited. Nasal biopsy specimens are difficult to obtain, and nasal secretions incompletely reflect the cellular and molecular events in the mucosa. IgE-mediated mast cell activation and the elaboration of factors promoting eosinophil development and chemotaxis are likely to participate in pathogenesis. OBJECTIVES: We sought to develop a murine model of allergic rhinitis, to use it to assess the role of IgE in pathogenesis, and to study the effects of IL-5 and eotaxin in the nasal mucosa. METHODS: A protein extract of Aspergillus fumigatus (Af) was instilled intranasally in mice. Histologic changes were examined in wild-type and IgE-deficient (IgE-/-) animals. The effect of eotaxin administration was assessed in wild-type and IL-5 transgenic mice. RESULTS: Af-treated mice developed a nasal mucosal eosinophil influx comparable to that described for humans. This histology was distinct from that observed in a murine model of Af-induced asthma. The pathology appeared over a time course similar to that reported for human subjects. There was no difference in the intensity of the mucosal inflammatory infiltrate of Af-treated IgE-/- mice compared with wild-type mice. Eotaxin was able to recruit eosinophils to the mucosa but only in IL-5 transgenic animals. CONCLUSION: We describe a murine model for allergic rhinitis with an eosinophilic infiltrate comparable to that found in human disease and have demonstrated that rhinitis can arise in the absence of IgE. We have shown that the eosinophil influx can be induced by eotaxin in the presence of IL-5.
Poppas, D. P., C. P. Pavlovich, et al. (1998). "Intravesical bacille Calmette-Guerin induces the antiangiogenic chemokine interferon-inducible protein 10." Urology 52(2): 268-75; discussion 275-6.
OBJECTIVES: Intravesical bacille Calmette-Guerin (BCG) induces a variety of cytokines into the urine of patients with superficial transitional cell carcinoma (TCC) of the bladder. Recent data have shown that some cytokines have antiangiogenic activity. We sought to determine whether the potently antiangiogenic chemokine interferon-inducible protein 10 (IP-10) and its inducing antiangiogenic cytokines, interferon-gamma (IFN-gamma) and interleukin-12 (IL-12), are increased during intravesical BCG immunotherapy of bladder TCC. METHODS: Voided urine samples were collected sequentially from 8 patients before and after each weekly intravesical BCG treatment and from 4 patients receiving maintenance BCG treatments. The urinary output of IP-10, IFN-gamma, and IL-12 over 12 post-treatment hours was assessed by enzyme-linked immunosorbent assay. In vitro BCG and cytokine stimulations of human TCC and primary endothelial cell lines were also performed, and their supernatants were studied for IP-10. RESULTS: In all cases after intravesical BCG, patient urine was found to contain significant elevations of IP-10. Urinary IFN-gamma and IL-12 levels also increased in similar patterns after intravesical BCG. The peak weekly cytokine response per patient usually occurred between the fourth and sixth treatment for IFN-gamma and IP-10, but was less predictable for IL-12. Human TCC and endothelial cell lines were able to secrete IP-10 in response to BCG or interferon stimulation in vitro. CONCLUSIONS: Our small series demonstrates that IP-10 and its inducing cytokines are elevated in response to intravesical BCG. These data suggest that, in addition to a cellular immune response, BCG may induce a cytokine-mediated antiangiogenic environment that aids in inhibiting future tumor growth and progression.
Nakamura, H., K. J. Haley, et al. (1998). "Differential regulation of eotaxin expression by TNF-alpha and PMA in human monocytic U-937 cells." Am J Physiol 275(3 Pt 1): L601-10.
Regulation of eotaxin expression was investigated in U-937 cells, a human monocyte-like cell line. Eotaxin mRNA was induced by tumor necrosis factor-alpha (TNF-alpha; 0.1-100 ng/ml) and phorbol 12-myristate 13-acetate (PMA; 0.01-1 microM). PMA-induced eotaxin mRNA expression was of greater magnitude and was maximal at a later time point than TNF-alpha-induced expression (16 h vs. 2 h after stimulation), which was consistent with eotaxin protein expression detected by immunocytochemistry. Dexamethasone (0.01-10 microM) decreased eotaxin mRNA expression in both TNF-alpha- and PMA-stimulated U-937 cells. PMA-induced eotaxin mRNA expression was inhibited by cycloheximide (10 microg/ml), whereas TNF-alpha-induced expression was not. The protein kinase C (PKC) inhibitor staurosporine (10-50 nM) inhibited PMA-induced eotaxin mRNA expression, whereas TNF-alpha-induced expression was enhanced by this reagent. These results suggest that eotaxin expression can be induced by more than one mechanism: the PMA-triggered pathway is mediated by PKC activation and requires new protein synthesis, whereas the TNF-alpha-triggered pathway is independent of PKC and protein synthesis. TNF-alpha- and PMA-induced pathways are both associated with nuclear factor-kappaB, because its binding activity was enhanced in the presence of these stimuli, and both pathways were limited by its inhibitor, diethyldithiocarbamate.
Matthews, A. N., D. S. Friend, et al. (1998). "Eotaxin is required for the baseline level of tissue eosinophils." Proc Natl Acad Sci U S A 95(11): 6273-8.
Eotaxin is an eosinophil-selective chemokine that is constitutively expressed in a variety of organs such as the intestine. Previous studies have demonstrated that the recruitment of eosinophils during inflammation is partially dependent on eotaxin, but the function of constitutive eotaxin during homeostasis has not been examined. To elucidate the biological role of this molecule, we now examine tissue levels of eosinophils in healthy states in wild-type and eotaxin-deficient mice. The lamina propria of the jejunum of wild-type mice is demonstrated to express eotaxin mRNA, but not mRNA for the related monocyte chemoattractant proteins. Wild-type mice contained readily detectable eosinophils in the lamina propria of the jejunum. In contrast, mice genetically deficient in eotaxin had a large selective reduction in the number of eosinophils residing in the jejunum. The reduction of tissue eosinophils was not limited to the jejunum, because a loss of thymic eosinophils was also observed in eotaxin-deficient mice. These studies demonstrate that eotaxin is a fundamental regulator of the physiological trafficking of eosinophils during healthy states. Because a variety of chemokines are constitutively expressed, their involvement in the baseline trafficking of leukocytes into nonhematopoietic tissue should now be considered.
Luster, A. D. (1998). "Chemokines--chemotactic cytokines that mediate inflammation." N Engl J Med 338(7): 436-45.
Luster, A. D., R. D. Cardiff, et al. (1998). "Delayed wound healing and disorganized neovascularization in transgenic mice expressing the IP-10 chemokine." Proc Assoc Am Physicians 110(3): 183-96.
IP-10 is a member of the alpha or cysteine-X amino acid-cysteine (CXC) chemokine family of chemotactic cytokines. High levels of IP-10 expression have been detected in a number of chronic human inflammatory conditions, including psoriasis, a common inflammatory disease of the skin. IP-10 has been shown to chemoattract activated T cells, inhibit the proliferation of endothelial cells, and inhibit the growth of tumors in vivo. To determine the capacity of IP-10 to modulate the inflammatory response in vivo, we have created transgenic mice that constitutively express IP-10 from keratinocytes. These mice developed normally and, in general, did not spontaneously recruit leukocytes into the skin or other organs that expressed the transgene. In addition, the transgenic mice had a normal cutaneous contact hypersensitivity cellular immune response. However, IP-10 transgenic mice had an abnormal wound healing response characterized by a more intense inflammatory phase and a prolonged and disorganized granulation phase with impaired blood vessel formation. These results have demonstrated that IP-10 can inhibit the neovascularization associated with a physiological response in vivo and have revealed a novel biologic activity of IP-10 as an inhibitor of wound healing.
Huang, W. W., E. A. Garcia-Zepeda, et al. (1998). "Molecular and biological characterization of the murine leukotriene B4 receptor expressed on eosinophils." J Exp Med 188(6): 1063-74.
The movement of leukocytes into tissues is regulated by the local production of chemical mediators collectively referred to as chemoattractants. Although chemoattractants constitute a diverse array of molecules, including proteins, peptides, and lipids, they all appear to signal leukocytes through a related family of seven transmembrane-spanning G protein-coupled receptors. The eosinophil is a potent proinflammatory cell that is attracted into tissues during allergic inflammation, parasitic infection, and certain malignancies. Since the molecular mechanisms controlling eosinophil recruitment are incompletely understood, we performed a degenerate polymerase chain reaction on cDNA isolated from murine eosinophils to identify novel chemoattractant receptors. We report the isolation of a cDNA that encodes a 351-amino acid glycoprotein that is 78% identical to a human gene that has been reported to be a purinoceptor (P2Y7) and a leukotriene B4 (LTB4) receptor (BLTR). Chinese hamster ovary (CHO) cells transfected with this cDNA specifically bound [3H]LTB4 with a dissociation constant of 0.6 +/- 0.1 nM. Furthermore, LTB4 induced a dose-dependent intracellular calcium flux in transfected CHO cells. In contrast, [35S]dATP did not specifically bind to these transfectants. This mRNA was expressed at high levels in interleukin 5-exposed eosinophils, elicited peritoneal macrophages and neutrophils, and to a lesser extent interferon gamma stimulated macrophages. Low levels of expression were detected in the lung, lymph node, and spleen of unchallenged mice. Western blot analysis detected the mBLTR protein in murine eosinophils and alveolar macrophages as well as human eosinophils. In addition, elevated levels of mBLTR mRNA were found in the lungs of mice in a murine model of allergic pulmonary inflammation in a time course consistent with the influx of eosinophils. Our findings indicate that this murine receptor is an LTB4 receptor that is highly expressed on activated leukocytes, including eosinophils, and may play an important role in mediating eosinophil recruitment into inflammatory foci.
Cook, E. B., J. L. Stahl, et al. (1998). "Epithelial cells are a major cellular source of the chemokine eotaxin in the guinea pig lung." Allergy Asthma Proc 19(1): 15-22.
Eotaxin is the major eosinophil chemoattractant found in bronchoalveolar lavage (BAL) fluid from sensitized guinea pigs after antigen challenge. In this study we have performed immunostaining for eotaxin in airways obtained from challenged animals and examined purified guinea pig lung cells (epithelial cells > 98% purity, mast cells > 90% purity) for eotaxin mRNA and protein. In the airways of antigen (ovalbumin) challenged animals, significant amounts of epithelial cell eotaxin immunostaining were observed. Northern analysis of total RNA obtained from unchallenged, freshly isolated airway epithelial cells contained high levels of eotaxin mRNA. Semi-pure and high purity lung mast cell preparations (challenged or unchallenged) did not express eotaxin mRNA. Western analysis of supernatant fluids obtained from incubated airway epithelial cells demonstrated detectable amounts of eotaxin protein, with the majority of the protein being cell-associated. Thus, airway epithelial cells are identified as a major cellular source of eotaxin in the guinea pig pulmonary system.
Agostini, C., M. Cassatella, et al. (1998). "Involvement of the IP-10 chemokine in sarcoid granulomatous reactions." J Immunol 161(11): 6413-20.
The accumulation of T cells and monocytes at sites of ongoing inflammation represents the earliest step in the series of events that lead to granuloma formation in sarcoidosis. In this study, we evaluated the pulmonary production of IFN-inducible protein 10 (IP-10), a CXC chemokine that stimulates the directional migration of activated T cells. Striking levels of IP-10 were demonstrated in the bronchoalveolar lavage (BAL) fluid of 24 patients with pulmonary sarcoidosis and lymphocytic alveolitis, as compared with patients with inactive disease or control subjects. A positive correlation was demonstrated between IP-10 levels and the number of sarcoid CD45R0+/CD4+ cells in the BAL. Immunochemistry, performed with an anti-human IP-10 polyclonal Ab in lymph nodes displaying prominent sarcoid granulomas, showed that cells bearing IP-10 were mainly epithelioid cells and CD68+ macrophages located inside granulomatous areas. Macrophages recovered from the BAL of sarcoid patients stained positive for IP-10 protein. Furthermore, alveolar macrophages isolated from sarcoid patients with T cell alveolitis and cultured for 24 h in presence of IFN-gamma secreted definite levels of IP-10 capable of inducing T cell chemiotaxis. Interestingly, alveolar lymphocytes recovered from patients with active sarcoidosis were CD4+ T cells expressing Th1 cytokines (IL-2 and IFN-gamma) and high levels of CXCR3. Taken together, these data suggest the potential role of IP-10 in regulating the migration and activation of T cells toward sites of sarcoid inflammatory process and the consequent granuloma formation.
Sarafi, M. N., E. A. Garcia-Zepeda, et al. (1997). "Murine monocyte chemoattractant protein (MCP)-5: a novel CC chemokine that is a structural and functional homologue of human MCP-1." J Exp Med 185(1): 99-109.
The chemokines are a large family of cytokines that control the recruitment of leukocytes in immune and inflammatory responses. We describe the isolation of a novel murine CC chemokine that, based on its biological and structural features, we have named monocyte chemoattractant protein (MCP)-5. MCP-5 mapped to the CC chemokine cluster on mouse chromosome 11 and was most closely related to human MCP-1 in structure (66% amino acid identity). Purified recombinant MCP-5 protein was a potent chemoattractant for peripheral blood monocytes, was only weakly active on eosinophils at high doses, and was inactive on neutrophils. MCP-5 induced a calcium flux in peripheral blood mononuclear cells, but not in purified murine eosinophils or neutrophils. Consistent with these results, MCP-5 induced a calcium flux in human embryonic kidney (HEK)-293 cells transfected with human and murine CCR2, a CC chemokine receptor expressed on monocytes. MCP-5 did not induce a calcium flux in HEK-293 cells transfected with CCR1, CCR3, or CCR5. Constitutive expression of MCP-5 mRNA was detected predominantly in lymph nodes, and its expression was markedly induced in macrophages activated in vitro and in vivo. Moreover, MCP-5 expression was up-regulated in the lungs of mice following aerosolized antigen challenge of sensitized mice, and during the host response to infection with Nippostrongylus brasiliensis. These data indicate that MCP-5 is a novel and potent monocyte active chemokine that is involved in allergic inflammation and the host response to pathogens.
Rothenberg, M. E., J. A. MacLean, et al. (1997). "Targeted disruption of the chemokine eotaxin partially reduces antigen-induced tissue eosinophilia." J Exp Med 185(4): 785-90.
The chemokines are a large group of chemotactic cytokines that regulate leukocyte trafficking and have recently been shown to inhibit human immunodeficiency virus entry into cells. Eotaxin is a C-C chemokine implicated in the recruitment of eosinophils in a variety of inflammatory disorders and, unlike all other eosinophil chemoattractants, is eosinophil specific. However, given the large number of chemoattractants that have activities on eosinophils, it is unclear whether eotaxin has an important role in vivo. Furthermore, it remains unclear why there is constitutive expression of eotaxin in healthy states in the absence of eosinophilic inflammation. To begin to determine the significance of eotaxin at baseline and during eosinophil-mediated disease processes, we have used targeted gene disruption to generate mice that are deficient in eotaxin. Such mice demonstrate that eotaxin enhances the magnitude of the early (but not late) eosinophil recruitment after antigen challenge in models of asthma and stromal keratitis. Surprisingly, a role for eotaxin in regulating the constitutive number of eosinophils in the peripheral circulation is also demonstrated. These results indicate a contributory role for eotaxin in the generation of peripheral blood and antigen-induced tissue eosinophilia.
Minshall, E. M., L. Cameron, et al. (1997). "Eotaxin mRNA and protein expression in chronic sinusitis and allergen-induced nasal responses in seasonal allergic rhinitis." Am J Respir Cell Mol Biol 17(6): 683-90.
Eotaxin is an eosinophil-specific chemokine associated with the recruitment of eosinophils to the site of allergic inflammation. The aims of this study were to determine the expression of eotaxin in nasal biopsies from allergic and nonallergic individuals with chronic severe sinusitis, and to examine whether the expression of this chemokine is upregulated following allergen challenge in the nasal mucosa of patients with allergic rhinitis. We also undertook to phenotype of inflammatory cells within the submucosa expressing eotaxin mRNA. Nasal turbinate tissue from 16 individuals with allergic or nonallergic chronic sinusitis and 10 normal controls were examined for the presence of eotaxin mRNA and immunoreactivity by in situ hybridization and immunocytochemistry. The numbers of cells expressing eotaxin mRNA were also determined after either allergen or diluent challenge in atopic subjects with a history of allergic rhinitis. There was a constitutive expression of eotaxin-immunoreactivity and the presence of eotaxin mRNA-positive cells in nasal biopsies from normal individuals. Compared with normal controls, the numbers of cells expressing eotaxin mRNA and protein were significantly increased in both allergic and nonallergic sinusitis (P < 0.001). Eotaxin mRNA was expressed by nasal epithelial cells and primarily colocalized to CD68-positive macrophages within the subepithelium. In subjects with allergic rhinitis, allergen challenge markedly increased the numbers of cells expressing eotaxin mRNA and immunoreactivity in the epithelial and subepithelial cell layers (P < 0.05). This could be largely attributed to a local increase in eotaxin production within the nasal tissues. The results of this study demonstrate the constitutive expression of eotaxin and show that the numbers of cells expressing eotaxin mRNA are increased within the epithelial and subepithelial layers of the nasal mucosa in individuals with chronic sinusitis. Furthermore, allergen challenge of the nasal mucosa in atopic subjects results in a local upregulation of eotaxin expression. These data suggest a potential role for this chemokine in the pathogenesis of allergic and nonallergic eosinophilic inflammation characterizing chronic sinusitis and allergic rhinitis.
Luster, A. D. and M. E. Rothenberg (1997). "Role of the monocyte chemoattractant protein and eotaxin subfamily of chemokines in allergic inflammation." J Leukoc Biol 62(5): 620-33.
Allergic inflammation is characterized by the tissue accumulation and activation of leukocytes rich in eosinophils. During these responses, there is marked induction of specific chemokines that are involved in regulating the recruitment and activation of these inflammatory cells. A subfamily of CC (or beta) chemokines composed of macrophage chemoattractant proteins (MCP) and eotaxin have emerged as cytokines involved in the recruitment and activation of the cells seen in allergic reactions. We now show that these chemokines are strikingly related in chromosomal location, gene structure, primary protein sequence, biological activity, and receptor usage. We also show that these chemokines are differentially regulated in human and animal models of allergic disease and perform distinct roles in vivo. We propose that this subfamily of chemokines plays a fundamental role in the development of allergic responses.
Lilly, C. M., H. Nakamura, et al. (1997). "Expression of eotaxin by human lung epithelial cells: induction by cytokines and inhibition by glucocorticoids." J Clin Invest 99(7): 1767-73.
Eotaxin is a potent and specific eosinophil chemoattractant that is mobilized in the respiratory epithelium after allergic stimulation. Pulmonary levels of eotaxin mRNA are known to increase after allergen exposure in sensitized animals. In this study we demonstrate that TNF alpha and IL-1beta induce the accumulation of eotaxin mRNA in the pulmonary epithelial cell lines A549 and BEAS 2B in a dose-dependent manner. Cytokine-induced A549 cell mRNA accumulation was maximal at 4 h and was significantly enhanced when the cells were costimulated with IFNgamma. TNFalpha- and IL-1beta-induced increases in eotaxin mRNA were diminished in a dose-dependent manner by the glucocorticoid dexamethasone and were augmented by the protein synthesis inhibitor cycloheximide. Cytokine-induced increases in eotaxin mRNA expression correlated with increased eotaxin protein production and secretion, and dexamethasone inhibition of cytokine-induced eotaxin mRNA augmentation was associated with diminished eotaxin protein secretion. These findings, together with the known kinetics of TNF alpha and IL-1beta mobilization in asthmatic airways and the potent eosinophil chemotactic effects of eotaxin, define a mechanism linking inflammatory cytokine mobilization to eosinophil recruitment that may be relevant to the pathogenesis of asthma.
Lamkhioued, B., P. M. Renzi, et al. (1997). "Increased expression of eotaxin in bronchoalveolar lavage and airways of asthmatics contributes to the chemotaxis of eosinophils to the site of inflammation." J Immunol 159(9): 4593-601.
Presently, there is considerable evidence for the participation of eosinophils in the pathophysiology of human bronchial asthma. Although increased numbers of eosinophils are present in the airways and bronchoalveolar lavage (BAL) fluid of atopic asthmatics, the mechanisms responsible for their preferential accumulation are still largely unknown. Eotaxin is a chemokine that promotes the selective recruitment of eosinophils. We report that atopic asthmatic patients have high concentrations of eotaxin in BAL fluid and an increased expression of eotaxin mRNA and protein in the epithelium and submucosa of their airways when compared with normal controls. In the BAL cells from asthmatic patients, eotaxin immunoreactivity colocalized predominantly to macrophages (62.2%), with a lesser contribution from T cells (16.3%) and eosinophils (8.9%). BAL fluid from asthmatics contained chemotactic activity for eosinophils that was attributable in part to the presence of eotaxin. Moreover, eotaxin was more effective at inducing in vitro eosinophil chemotaxis when eosinophils were stimulated with IL-5 (a cytokine that enhances the effector capacity of mature eosinophils). These observations suggest that eotaxin contributes to the pathogenesis of asthma by the specific recruitment of eosinophils into the airways.
Garcia-Zepeda, E. A., M. E. Rothenberg, et al. (1997). "Genomic organization, complete sequence, and chromosomal location of the gene for human eotaxin (SCYA11), an eosinophil-specific CC chemokine." Genomics 41(3): 471-6.
Eotaxin is a CC chemokine that is a specific chemoattractant for eosinophils and is implicated in the pathogenesis of eosinophilic inflammatory diseases, such as asthma. We describe the genomic organization, complete sequence, including 1354 bp 5' of the RNA initiation site, and chromosomal localization of the human eotaxin gene. Fluorescence in situ hybridization analysis localized eotaxin to human chromosome 17, in the region q21.1-q21.2, and the human gene name SCYA11 was assigned. We also present the 5' flanking sequence of the mouse eotaxin gene and have identified several regulatory elements that are conserved between the murine and the human promoters. In particular, the presence of elements such as NF-kappa B, interferon-gamma response element, and glucocorticoid response element may explain the observed regulation of the eotaxin gene by cytokines and glucocorticoids.
Cassatella, M. A., S. Gasperini, et al. (1997). "Regulated production of the interferon-gamma-inducible protein-10 (IP-10) chemokine by human neutrophils." Eur J Immunol 27(1): 111-5.
Interferon-gamma (IFN-gamma)-inducible protein-10 (IP-10), a member of the C-X-C sub-family of chemokines, is known to be produced by monocytes, lymphocytes, keratinocytes and endothelial cells in response to IFN-gamma. Here, we show that human polymorphonuclear neutrophils (PMN) also have the ability to produce IP-10. IFN-gamma alone had a modest effect on IP-10 mRNA accumulation, whereas tumor necrosis factor-alpha (TNF-alpha), yeast particles opsonized with IgG (Y-IgG), lipopolysaccharide (LPS), and formyl-methionyl-leucyl-phenylalanine (fMLP) all failed to up-regulate IP-10 gene expression. However, stimulation of neutrophils with IFN-gamma in combination with either TNF-alpha or LPS (but not with Y-IgG or fMLP) resulted in a considerable induction of IP-10 mRNA transcripts, as well as in the extracellular release of the protein. In contrast, the best inducer of IP-10 release from peripheral blood mononuclear cells was IFN-gamma alone. Furthermore, mRNA stabilization analyses demonstrated that IP-10 mRNA isolated from PMN stimulated with IFN-gamma only, or with IFN-gamma plus either TNF-alpha or LPS, had similar half-lives. Finally, we found that interleukin-10, a known inhibitor of chemokine production in PMN, moderately suppressed the extracellular production of IP-10 in neutrophils stimulated with IFN-gamma plus either LPS or TNF-alpha. Since IP-10 is a potent chemoattractant for activated T lymphocytes, the ability of neutrophils to produce IP-10 might contribute to the evolution and progression of the inflammatory response.
Ayehunie, S., E. A. Garcia-Zepeda, et al. (1997). "Human immunodeficiency virus-1 entry into purified blood dendritic cells through CC and CXC chemokine coreceptors." Blood 90(4): 1379-86.
Blood dendritic cells (DC) are susceptible to both macrophage (M) and T-cell line (T) tropic human immunodeficiency virus type 1. The CC chemokines RANTES, macrophage inflammatory protein-1alpha (MIP-1alpha), MIP-1beta, eotaxin, and, to a lesser extent, monocyte chemoattractant protein-1 (MCP-1) and MCP-4 blocked entry of M-tropic virus into blood DC. The CXC chemokine, SDF-1, a fusin (CXCR4 chemokine receptor) ligand, and an antifusin antibody inhibited DC entry by T-tropic virus. Purified blood DC contained CCR1, CCR2, CCR3, and CCR5 as well as the CXCR4 chemokine receptor RNA transcripts and high levels of fusin on the cell surface. The coexpression of multiple chemokine receptors offers a molecular mechanism to explain the permissiveness of DC for both M- and T-tropic viruses.
Rothenberg, M. E., R. Ownbey, et al. (1996). "Eotaxin triggers eosinophil-selective chemotaxis and calcium flux via a distinct receptor and induces pulmonary eosinophilia in the presence of interleukin 5 in mice." Mol Med 2(3): 334-48.
BACKGROUND: Understanding the processes that control selective eosinophilia is of fundamental importance in a variety of human diseases (e.g., allergies, parasitic infections, malignancy). Interleukin 5, an eosinophil-specific growth and activating factor, and eotaxin appear to collaborate in this process. Eotaxin is a recently described chemotactic factor that belongs to the C-C (or beta) chemokine family and has been implicated in animal and human eosinophilic inflammatory states. We have recently reported the molecular characterization of murine eotaxin and now report the biological properties of purified recombinant murine eotaxin in vitro and in vivo in the presence or absence of interleukin 5 (IL-5) in mice. MATERIALS AND METHODS: Murine eotaxin was expressed in bacteria and purified by affinity chromatography and HPLC. Activity was tested in vitro by examining chemotactic and calcium flux responses of purified murine leukocytes. Additionally, desensitization of calcium flux responses to other chemokines, eosinophil survival assays, and basophil histamine release were examined. Finally, eotaxin was delivered to wild-type or IL-5 transgenic mice and the host response was examined. RESULTS: Eotaxin had activity only when the recombinant molecule had the native mature amino terminus and contained the first 25 amino acids of the mature protein. It was active in vitro at an effective concentration between 10 and 100 ng/ml in both chemotaxis and calcium flux assays toward eosinophils, but not macrophages or neutrophils. Furthermore, intranasal or subcutaneous application of eotaxin selectively recruited large numbers of eosinophils into the mouse lung and skin, respectively, only in the presence of interleukin 5. Macrophage inflammatory protein-1 alpha, a related C-C chemokine active on eosinophils, and eotaxin were not able to cross-desensitize. Eotaxin had no affect on the in vitro survival of eosinophils and did not induce basophil histamine release. CONCLUSIONS: Mouse eotaxin is an eosinophil specific chemoattractant that has a markedly enhanced effect in vivo in the presence of another eosinophil selective cytokine IL-5, and utilizes a signal transduction receptor pathway that is distinct from that utilized by macrophage inflammatory protein-1 alpha. This data suggests that the development of tissue eosinophilia in vivo involves a two-step mechanism elicited by interleukin 5 and eotaxin.
MacLean, J. A., R. Ownbey, et al. (1996). "T cell-dependent regulation of eotaxin in antigen-induced pulmonary eosinophila." J Exp Med 184(4): 1461-9.
T lymphocytes have been implicated in controlling the recruitment of eosinophils into the lung in murine models of allergic asthma. The mechanism by which T cells assist in the recruitment of eosinophils to the lung in these models is not completely understood. We hypothesized that eosinophil-active chemokines might be regulated by antigen (Ag)-induced T cell activation in vivo and thereby mediate T cell-dependent eosinophil recruitment. To test this hypothesis, we examined the effect of an anti-CD3 mAb on Ag-induced pulmonary eosinophilia and correlated this with the expression of three eosinophil-active chemokines: eotaxin, macrophage inflammatory protein (MIP)-1 alpha, and RANTES. We found that Ag-induced pulmonary eosinophilia was associated with the induction of eotaxin and MIP-1 alpha, but not RANTES mRNA. Prechallenge treatment with anti-CD3 mAb inhibited eotaxin, but not MIP-1 alpha and RANTES mRNA induction, and significantly reduced eosinophil accumulation in the lung. In addition, Ag-specific antibody responses and mast cell degranulation after Ag challenge in sensitized mice were not affected by T cell elimination, and were not sufficient to induce the expression of eotaxin and cause pulmonary eosinophilia. These findings suggest that eotaxin is one of the molecular links between Ag-specific T cell activation and the recruitment of eosinophils into the airways.
Garcia-Zepeda, E. A., M. E. Rothenberg, et al. (1996). "Human eotaxin is a specific chemoattractant for eosinophil cells and provides a new mechanism to explain tissue eosinophilia." Nat Med 2(4): 449-56.
Eotaxin is an eosinophil-specific chemoattractant that has been recently identified in rodent models of asthma and host response against tumors. To determine whether a similar molecule might play a role in human inflammatory diseases characterized by eosinophilia, we isolated the human eotaxin gene. We demonstrate that human eotaxin is an early response gene of cytokine-stimulated epithelial and endothelial cells, and is induced in peripheral blood eosinophils by interleukin-3. Eotaxin is directly chemotactic for eosinophils, but not mononuclear cells or neutrophils. Eotaxin messenger RNA accumulates markedly in the lesions of patients with inflammatory bowel disease (ulcerative colitis and Crohn's disease), but not in the lesions of patients with diverticulitis. These results now provide a mechanism involving eotaxin to explain the eosinophil infiltration seen in a variety of human disease; as such, an eotaxin antagonist may be a novel therapy for certain human diseases characterized by tissue eosinophilia.
Garcia-Zepeda, E. A., C. Combadiere, et al. (1996). "Human monocyte chemoattractant protein (MCP)-4 is a novel CC chemokine with activities on monocytes, eosinophils, and basophils induced in allergic and nonallergic inflammation that signals through the CC chemokine receptors (CCR)-2 and -3." J Immunol 157(12): 5613-26.
The chemokines are a large family of cytokines that regulate the complex and precise recruitment of immune cells into inflammatory foci. To fully appreciate their role in the pathogenesis of human diseases, the entire spectrum of chemokines, their receptors, their cellular targets, and mechanisms of regulation need to be delineated. Using eotaxin as a probe, we isolated a cDNA for a novel human beta (or CC) chemokine that, based on its biological and structural features, we have named monocyte chemoattractant protein (MCP)-4. Purified recombinant MCP-4 protein was a potent chemoattractant for monocytes and eosinophils and stimulated histamine release from basophils. MCP-4 induced a calcium flux in HEK-293 cells transfected with the monocyte selective MCP-1 receptor (CCR-2B) and the eosinophil selective eotaxin receptor (CCR-3), but not in the more widely expressed CCR-1 or CCR-5. This novel chemokine is expressed in TNF-alpha and IL-1 activated epithelial and endothelial cells in vitro, and in the epithelial mucosa of patients with both Th2-type allergic and Th1-type nonallergic sinusitis. Furthermore, both IFN-gamma and IL-4, products of Th1 and Th2 cells, respectively, synergized with TNF-alpha and IL-1 in inducing MCP-4 mRNA accumulation. These properties of MCP-4 offer a molecular explanation for the observed accumulation of monocytes, eosinophils and basophils in both Th1- and Th2-type immune responses.
Gao, J. L., A. I. Sen, et al. (1996). "Identification of a mouse eosinophil receptor for the CC chemokine eotaxin." Biochem Biophys Res Commun 223(3): 679-84.
The CC chemokine eotaxin is a selective chemoattractant for eosinophils in vitro and induces eosinophil migration in vivo. Here we show that the mouse orphan receptor previously named macrophage inflammatory protein-1 alpha receptor-like 2 is a functional eotaxin receptor. For consistency with other nomenclature, we have renamed the receptor mouse CC chemokine receptor 3. Human and mouse eotaxin, but not other chemokines, induced transient increases in [Ca2+]i in human embryonic kidney 293 cells expressing the receptor. RNA for the receptor was abundant in primary eosinophils, but at low levels in neutrophils and macrophages. These properties make this receptor the best known candidate to mediate mouse eosinophil responses to eotaxin.
Rothenberg, M. E., A. D. Luster, et al. (1995). "Constitutive and allergen-induced expression of eotaxin mRNA in the guinea pig lung." J Exp Med 181(3): 1211-6.
Eotaxin is a member of the C-C family of chemokines and is related during antigen challenge in a guinea pig model of allergic airway inflammation (asthma). Consistent with its putative role in eosinophilic inflammation, eotaxin induces the selective infiltration of eosinophils when injected into the lung and skin. Using a guinea pig lung cDNA library, we have cloned full-length eotaxin cDNA. The cDNA encodes a protein of 96 amino acids, including a putative 23-amino acid hydrophobic leader sequence, followed by 73 amino acids composing the mature active eotaxin protein. The protein-coding region of this cDNA is 73, 71, 50, and 48% identical in nucleic acid sequence to those of human macrophage chemoattractant protein (MCP) 3, MCP-1, macrophage inflammatory protein (MIP) 1 alpha, and RANTES, respectively. Analysis of genomic DNA suggested that there is a single eotaxin gene in guinea pig which is apparently conserved in mice. High constitutive levels of eotaxin mRNA expression were observed in the lung, while the intestines, stomach, spleen, liver, heart, thymus, testes, and kidney expressed lower levels. To determine if eotaxin mRNA levels are elevated during allergen-induced eosinophilic airway inflammation, ovalbumin (OVA)-sensitized guinea pigs were challenged with aerosolized antigen. Compared with the lungs from saline-challenged animals, eotaxin mRNA levels increased sixfold within 3 h and returned to baseline by 6 h. Thus, eotaxin mRNA levels are increased in response to allergen challenge during the late phase response. The identification of constitutive eotaxin mRNA expression in multiple tissues suggests that in addition to regulating airway eosinophilia, eotaxin is likely to be involved in eosinophil recruitment into other tissues as well as in baseline tissue homing.
Rothenberg, M. E., A. D. Luster, et al. (1995). "Murine eotaxin: an eosinophil chemoattractant inducible in endothelial cells and in interleukin 4-induced tumor suppression." Proc Natl Acad Sci U S A 92(19): 8960-4.
Guinea pig eotaxin is a recently described member of the Cys-Cys family of chemokines and is involved in a guinea pig model of asthma. To determine whether eotaxin is a distinctive member of this family and to understand its physiologic role, we have cloned the mouse eotaxin gene and determined its structure and aspects of its biologic function. The sequence relationship between the mouse and guinea pig genes indicates that eotaxin is indeed a distinct member of the chemokine family. Moreover, murine eotaxin maps to a region of mouse chromosome 11 that encodes other Cys-Cys chemokines. In addition, recombinant murine eotaxin protein has direct chemoattractant properties for eosinophils. The eotaxin gene is widely (but not ubiquitously) expressed in normal mice and is strongly induced in cultured endothelial cells in response to interferon gamma. Eotaxin is also induced locally in response to the transplantation of interleukin 4-secreting tumor cells, indicating that it likely contributes to the eosinophil recruitment and antitumor effect of interleukin 4. Such responses suggest that eotaxin may be involved in multiple inflammatory states.
Post, T. W., C. R. Bozic, et al. (1995). "Molecular characterization of two murine eosinophil beta chemokine receptors." J Immunol 155(11): 5299-305.
beta or C-C chemokines including RANTES, MCP-3, MIP-1 alpha, and eotaxin have been implicated in the pathogenesis of eosinophilic inflammation. Two human beta chemokine receptors have been cloned and characterized: the MIP-1 alpha/RANTES receptor or C-C chemokine receptor 1 (CCR-1) and the MCP-1 receptor or C-C chemokine receptor 2 (CCR-2). However, no murine beta chemokine receptors have thus far been reported. Molecular cloning from mouse genomic DNA and cDNA libraries yielded two murine beta chemokine receptors with 79% and 65% sequence identity with human CCR-1, and 50% and 55% with human CCR-2. COS cells transiently transfected with the murine homologue of human CCR-1 bind murine MIP-1 alpha and human RANTES with Kds of 3.4 nM and 4.2 nM and murine MIP-1 beta with an EC50 of 8.9 nM. The other murine beta chemokine receptor, which we have designated murine CCR-3, also binds murine MIP-1 alpha. The mRNAs for both receptors are expressed in eosinophils from IL-5 transgenic mice. The level of murine CCR-3 mRNA in these mouse eosinophils exceeds that of CCR-1 mRNA and approaches actin levels. Murine MIP-1 alpha was found to be a potent chemoattractant for murine eosinophils. Our findings suggest that the murine MIP-1 alpha ligand/receptor system is an important mediator of murine eosinophil trafficking.
Luster, A. D., S. M. Greenberg, et al. (1995). "The IP-10 chemokine binds to a specific cell surface heparan sulfate site shared with platelet factor 4 and inhibits endothelial cell proliferation." J Exp Med 182(1): 219-31.
IP-10 is a member of the chemokine family of cytokines and is induced in a variety of cells in response to interferon gamma and lipopolysaccharide. The self-aggregation common to many chemokines, including IP-10, has hindered the identification of a specific IP-10 receptor. Using an IP-10 alkaline phosphatase fusion protein that fortuitously blocks this self-aggregation, we have identified an IP-10 binding site on a variety of cells including endothelial, epithelial, and hematopoietic cells. This binding site has a Kd of 25 nM, is inhibited by recombinant murine or human IP-10, and is dependent on the presence of cell surface heparan sulfate proteoglycans (HSPG). This conclusion is based on the findings that IP-10 binding to cells is: (a) inhibited by heparin and heparan sulfate; (b) sensitive to a 1 M NaCl wash; (c) eliminated by treatment with heparinase and trypsin; and (d) absent on mutant CHO cells that do not express cell surface HSPG. Platelet factor 4 (PF4), but not IL-8, monocyte chemoattractant protein-1, RANTES, monocyte inflammatory protein (MIP)-1 alpha, or MIP-1 beta, can compete effectively with IP-10 for binding to the cell surface. Furthermore, IP-10 shares with PF4 the ability to inhibit endothelial cell proliferation (IC50 = 150 nM). These studies demonstrate specificity in the interaction of chemokines and HSPG, and they define IP-10 and PF4 as a distinct subset of chemokines sharing an HSPG-binding site and angiostatic properties.
Gattass, C. R., L. B. King, et al. (1994). "Constitutive expression of interferon gamma-inducible protein 10 in lymphoid organs and inducible expression in T cells and thymocytes." J Exp Med 179(4): 1373-8.
Interferon gamma-inducible protein 10 (IP-10), a member of a family of small proinflammatory chemotactic polypeptides, is expressed in interferon gamma-stimulated keratinocytes, macrophages, fibroblasts, and endothelial cells. Here we report that IP-10 is also expressed by activated but not resting T hybridoma cells, normal T cells, and thymocytes. Although resting lymphocytes did not synthesize IP-10, surprisingly high levels of IP-10 transcripts were found in lymphoid organs (spleen, thymus, and lymph nodes). Thymic and splenic stromal cells were found to express constitutively high levels of both IP-10 mRNA and protein, accounting for the high level of spontaneous expression in lymphoid tissue. Therefore, in addition to its role as a proinflammatory cytokine, IP-10 may participate in T cell effector function and perhaps T cell development.
Luster, A. D. and P. Leder (1993). "IP-10, a -C-X-C- chemokine, elicits a potent thymus-dependent antitumor response in vivo." J Exp Med 178(3): 1057-65.
IP-10 is a member of the -C-X-C-chemokine superfamily of proinflammatory cytokines whose secretion is induced by interferon gamma (IFN-gamma) and lipopolysaccharide (LPS). To date no function has been described for IP-10. We have genetically engineered tumor cells to secrete high levels of murine IP-10 and demonstrate that while IP-10 has no effect on the growth of these tumor cells in culture, it elicits a powerful host-mediated antitumor effect in vivo. The IP-10 antitumor response is T lymphocyte dependent, non-cell autonomous, and appears to be mediated by the recruitment of an inflammatory infiltrate composed of lymphocytes, neutrophils, and monocytes. These results document an important biologic property of IP-10 and raise the possibility that some of the T cell-directed effects of IFN-gamma and LPS may be mediated by this chemokine.
Smoller, B. R., A. D. Luster, et al. (1991). "Fixed drug eruptions: evidence for a cytokine-mediated process." J Cutan Pathol 18(1): 13-9.
Fixed drug eruptions (FDE) are immunologic reactions to drugs which produce erythematous plaques or blisters that characteristically recur at the same cutaneous sites with repeated antigenic challenges. While a detailed pathogenesis of these lesions remains obscure, T-lymphocyte infiltration has been documented repeatedly. In this study, we tried to determine if FDE were mediated, at least in part, by cytokines, such as gamma-interferon. We examined biopsies from 6 cases of clinically well-documented FDE with an HLA-DR antibody, LN3, and an antibody to gamma IP-10 (IP-10), a protein expressed by keratinocytes, monocytes, lymphocytes and endothelial cells following exposure to gamma-interferon. We found staining of the dermal lymphocytes with anti-HLA-DR antibody in all 6 cases examined. Keratinocytes and endothelial cells showed only focal staining at the antibody concentrations used. In addition, there was keratinocyte staining with the IP-10 antibody at all levels of the epidermis, with accentuation in areas of blister formation. There was more intense staining of keratinocytes with the IP-10 antibody in cases with accumulations of HLA-DR positive lymphocytes in the dermis. We believe that these findings are consistent with the hypothesis that FDE represent cell-mediated immunologic responses to a variety of antigens, and further, that the histologic alterations can be explained, at least in part, by a cytokine-mediated process.
Khandke, L., J. F. Krane, et al. (1991). "Cyclosporine in psoriasis treatment. Inhibition of keratinocyte cell-cycle progression in G1 independent of effects on transforming growth factor alpha/epidermal growth factor receptor pathways." Arch Dermatol 127(8): 1172-9.
Cyclosporine, an immunosuppressive drug, is effective in the treatment of recalcitrant psoriasis. Previous work suggested that keratinocyte hyperproliferation and inflammation are linked in psoriasis and that immune mechanisms participate in the pathogenesis of psoriasis. Transforming growth factor (TGF) alpha may be an important regulatory factor of epidermal growth as overproduction of TGF-alpha is associated with epidermal hyperplasia in psoriatic plaques and epidermal growth factor receptors are overexpressed in psoriatic epithelium. In this study, the effects of cyclosporine on cultured human keratinocytes were examined. Cyclosporine specifically inhibited keratinocyte cell-cycle progression in the G1 phase without causing keratinocytes to terminally differentiate. Cyclosporine did not decrease the expression of TGF-alpha or epidermal growth factor receptors. These results suggest that the effects of cyclosporine on psoriatic skin are unrelated to direct effects on autocrine growth regulation of keratinocytes via TGF-alpha production or of epidermal growth factor receptor modulation.
Brooks, D. G., W. Q. Qiu, et al. (1989). "Structure and expression of human IgG FcRII(CD32). Functional heterogeneity is encoded by the alternatively spliced products of multiple genes." J Exp Med 170(4): 1369-85.
The structural heterogeneity of the human low affinity receptor for IgG, FcRII(CD32), has been elucidated through the isolation, characterization, and expression of cDNA clones derived from myeloid and lymphoid RNA. These clones predict amino acid sequences consistent with integral membrane glycoproteins with single membrane spanning domains. The extracellular domains display sequence homology to other Fc gamma Rs and members of the Ig supergene family. A minimum of three genes (Fc gamma RIIa, IIa', and Fc gamma RIIb) encode these transcripts, which demonstrate highly related extracellular and membrane spanning domains. IIa/IIa' differ substantially in the intracytoplasmic domain from IIb. Alternative splicing of the IIb gene generates further heterogeneity in both NH2- and COOH-terminal domains of the predicted proteins. Comparison to the murine homologues of these molecules reveals a high degree of conservation between the products of one of these genes, Fc gamma RIIb, and the murine beta gene in primary sequence, splicing pattern, and tissue distribution. In contrast, the sequence of IIa' indicates its relationship to the beta-like genes, with mutation giving rise to a novel cytoplasmic domain, while IIa is a chimera of both alpha- and beta-like genes. Expression of these cDNA molecules by transfection results in the appearance of IgG binding molecules that bear the epitopes defined by the FcRII(CD32) mAbs previously described.
Weinshank, R. L., A. D. Luster, et al. (1988). "Function and regulation of a murine macrophage-specific IgG Fc receptor, Fc gamma R-alpha." J Exp Med 167(6): 1909-25.
Ligand binding specificities of two cloned murine Fc gamma Rs (Fc gamma R-alpha, Fc gamma R-beta ) were determined by gene transfer into Fc gamma R negative cell lines. Both receptors were expressed as full-length molecules capable of IgG immune complex binding that was inhibitable by the mAb 2.4G2. The ligand binding profiles of these receptors were indistinguishable whereby both bound immune-complexed mouse IgG1, IgG2a, and IgG2b, but not IgG3. Neither receptor could bind monomeric IgG2a, indicating these receptors to be low-affinity IgG Fc receptors. Accumulation of the Fc gamma R-alpha mRNA can be induced with murine IFN-gamma at a concentration of 200 U/ml in the macrophage-like cell lines RAW 264.7 and J774a. The time course for induction indicates that the mRNA accumulation is transient but does not return to the uninduced level even after 50 h of treatment. Fc gamma R-beta mRNA was not induced by IFN-gamma, rather its expression was down modulated in mouse peritoneal macrophages. Both RAW and J774a cells lines exhibited increased receptor levels after IFN-gamma stimulation as measured by 125I-2.4G2 and ligand binding. In the absence of IFN-gamma, the RAW and J774a cell lines were minimally phagocytic, while P388D1 cells were actively phagocytic. In the presence of IFN-gamma, however, RAW 264.7 and J774a cells were induced to become actively phagocytic. Induction of Fc gamma R-alpha mRNA and protein by IFN-gamma may be part of the process by which macrophages become activated to engulf antibody-coated particles.
Luster, A. D., R. L. Weinshank, et al. (1988). "Molecular and biochemical characterization of a novel gamma-interferon-inducible protein." J Biol Chem 263(24): 12036-43.
A cDNA clone has been isolated from mRNA derived from the monocytic cell line U937, which detects an mRNA that is present and inducible by gamma-interferon (IFN gamma) in cells of the hematopoietic lineage and absent but inducible in non-hematopoietic cells. Following recombinant IFN gamma (rIFN gamma) treatment, mRNA accumulation can be detected within 30 min, plateaus at 24 h, and remains elevated for several days. This mRNA accumulation is due, at least in part, to increased transcription and is not inhibited by cycloheximide, although cycloheximide alone induces both mRNA accumulation and transcription of this gene. rIFN gamma is a more potent inducing agent than either rIFN alpha or rIFN beta. Polyclonal monospecific antiserum raised to the longest open reading frame expressed in Escherichia coli immunoprecipitates multiple polypeptides that are inducible by rIFN gamma in human monocytes, fibroblasts, endothelial cells, and keratinocytes. In pulse-chase experiments analyzed under reducing conditions, a 30-kDa polypeptide (referred to as IP-30) is either secreted or converted intracellularly into a 25-kDa protein; when analyzed under nonreducing conditions, the two intracellular forms have apparent molecular masses of 25 and 20 kDa, and the extracellular protein is found in two forms of apparent molecular mass 50 and 25 kDa. These data suggest that the intracellular form contains intrachain disulfide bonds, and the extracellular form is involved in both intrachain and interchain disulfide bonding. Indirect immunofluorescence microscopy reveals a punctate fluorescence pattern in monocytes consistent with a vesicular subcellular location. These data are consistent with IP-30 being a novel IFN gamma-inducible protein which may be lysosomal in location.
Gottlieb, A. B., A. D. Luster, et al. (1988). "Detection of a gamma interferon-induced protein IP-10 in psoriatic plaques." J Exp Med 168(3): 941-8.
The pathologic features of psoriatic plaques are inflammation and increased epidermal turnover. IP-10, a cytokine the expression of which is induced by gamma-interferon, is a member of a family of soluble mediators with inflammatory and growth-promoting activities. IP-10 protein was detected in keratinocytes and the dermal infiltrate from active psoriatic plaques using an affinity-purified rabbit anti-IP-10 antibody in immunoperoxidase studies. Successful treatment of active plaques decreased IP-10 expression in plaques. These results were corroborated by Northern blot analysis with an IP-10 cDNA probe. We have previously detected activated T cells and HLA-DR keratinocytes in active psoriatic plaques. Since IP-10 is detected in delayed cellular immune responses, the present study further points to the role of ongoing cellular immune responses in the pathogenesis of psoriasis.
Luster, A. D., S. C. Jhanwar, et al. (1987). "Interferon-inducible gene maps to a chromosomal band associated with a (4;11) translocation in acute leukemia cells." Proc Natl Acad Sci U S A 84(9): 2868-71.
An interferon-inducible cytokine, IP-10, containing homology to a family of proteins having chemotactic (platelet factor 4, beta-thromboglobulin) and mitogenic (connective tissue-activating peptide III) activities has been mapped to chromosome 4 at band q21, a locus associated with an acute monocytic/B-lymphocyte lineage leukemia that exhibits the nonrandom translocation t(4;11)(q21;q23). In situ hybridization of t(4;11)(q21;q23)-carrying leukemic cells revealed that the IP-10 gene is proximal to the breakpoint of this translocation. No DNA rearrangement was evident when the IP-10 gene was hybridized to genomic DNA isolated from two patients' leukemic cells that contain t(4;11)(q21;q23). However, restriction fragment length polymorphism in the 5' region of the IP-10 gene was detected. The ETS1 protooncogene is located at 11q23 and is known to translocate to chromosome 4 in t(4;11) (q21;q23) and into the interferon gene cluster in (9;11) (p22;q23). Both translocations are associated with acute monocytic leukemia. These results suggest a model in which juxtaposition of genetic loci regulated by antiproliferative signals, such as interferon, next to an oncogene, like ETS1, could effectively short circuit homeostatic control circuits and contribute to the neoplastic state.
Luster, A. D. and J. V. Ravetch (1987). "Biochemical characterization of a gamma interferon-inducible cytokine (IP-10)." J Exp Med 166(4): 1084-97.
An IFN-gamma-inducible protein, IP-10, has previously been described to belong to a gene family of chemotactic and mitogenic proteins, associated with inflammation and proliferation. Biochemical characterization of this predicted protein has been pursued through the development of polyclonal monospecific antisera to recombinant protein and synthetic peptides. These reagents establish that the IP-10 protein is secreted from a variety of cells (endothelial, monocyte, fibroblast, and keratinocyte) in response to IFN-gamma. Posttranslational processing occurs in the biosynthesis of this protein, resulting in a 6-7-kD species, which may reflect COOH-terminal cleavage. Pulse-chase studies indicate that this processing is a rapid event in the primary cell lines studied, completed in the 30-min labeling period. A model is presented for the processing and secondary structure of this protein. In an accompanying study, Kaplan, et al. using these antisera, demonstrate that the IP-10 protein is associated, in vivo, with a delayed-type hypersensitivity response.
Luster, A. D. and J. V. Ravetch (1987). "Genomic characterization of a gamma-interferon-inducible gene (IP-10) and identification of an interferon-inducible hypersensitive site." Mol Cell Biol 7(10): 3723-31.
The genomic organization of a gamma-interferon-inducible gene, IP-10, reveals three introns that interrupt the transcribed sequence into four functional domains. Comparison of the intron-exon structure of this gene to the gene for an homologous chemotactic platelet protein, platelet factor 4, establishes that both genes are interrupted in precisely the same positions within homologous codons; this demonstrates that they belong to a gene family that evolved from a common ancestor. IP-10 and PF4 are two members of a newly described gene family that is likely to include the homologous chemotactic and mitogenic platelet basic proteins (connective tissue-activating protein III and beta-thromboglobulin), the transformation-related protein 9E3, and 310c, a mitogen-stimulated leukocyte protein. A DNase I-hypersensitive site has been found in responsive cells in a region upstream of the RNA initiation site. This hypersensitive site is induced by gamma interferon and thus provides a structural basis for the transcriptional activation seen for this gene by gamma interferon.
Kaplan, G., A. D. Luster, et al. (1987). "The expression of a gamma interferon-induced protein (IP-10) in delayed immune responses in human skin." J Exp Med 166(4): 1098-108.
Our knowledge of the induction of new molecules by IFN-gamma has led to the characterization of IP-10 and the preparation of a monospecific, polyclonal antibody. Using this reagent we have now examined inflammatory states occurring in human skin and used immunocytochemical staining for the expression of both Ia and IP-10 determinants. After evoking a delayed-type response to purified protein derivative of tuberculin (PPD), we noted the presence of IP-10 in dermal macrophages and endothelial cells. Intense staining of the basal layer of epidermal keratinocytes was prominent at 41 h, and by 1 wk the entire epidermis was staining. The comparison of the amount of IP-10 secreted by keratinocytes vs. macrophages, fibroblasts, and endothelial cells revealed that keratinocytes were by far the major producers of this molecule. The expression of Ia occurred in conjunction with IP-10. The injection of rIFN-gamma mimicked many of the features of the PPD response, including the expression of both Ia and IP-10 by epidermal keratinocytes. Coexpression was also found in the natural lesions of tuberculoid leprosy and cutaneous Leishmaniasis. However, it was absent in lepromatous leprosy, a state where activated T lymphocytes are not present. We suggest that the local production of IFN-gamma by T cells of the dermal infiltrate induces IP-10 formation in both the dermis and epidermis. IP-10 and Ia then serve as specific markers of immune IFN and its possible influence on effector cells of the cell mediated immune response.
Ravetch, J. V., A. D. Luster, et al. (1986). "Structural heterogeneity and functional domains of murine immunoglobulin G Fc receptors." Science 234(4777): 718-25.
Binding of antibodies to effector cells by way of receptors to their constant regions (Fc receptors) is central to the pathway that leads to clearance of antigens by the immune system. The structure and function of this important class of receptors on immune cells is addressed through the molecular characterization of Fc receptors (FcR) specific for the murine immunoglobulin G isotype. Structural diversity is encoded by two genes that by alternative splicing result in expression of molecules with highly conserved extracellular domains and different transmembrane and intracytoplasmic domains. The proteins encoded by these genes are members of the immunoglobulin supergene family, most homologous to the major histocompatibility complex molecule E beta. Functional reconstitution of ligand binding by transfection of individual FcR genes demonstrates that the requirements for ligand binding are encoded in a single gene. These studies demonstrate the molecular basis for the functional heterogeneity of FcR's, accounting for the possible transduction of different signals in response to a single ligand.
Luster, A. D., J. C. Unkeless, et al. (1985). "Gamma-interferon transcriptionally regulates an early-response gene containing homology to platelet proteins." Nature 315(6021): 672-6.
Interferons are a family of proteins first identified by their ability to induce cellular resistance to infection by many viruses. In addition to the antiviral properties it shares with the alpha- and beta-interferons, gamma-interferon (IFN-gamma), a lymphokine secreted by activated T cells, activates macrophages, stimulates B cells, increases fibroblast and endothelial cell resistance to many nonviral intracellular parasites and modulates cell-surface proteins central to immune cell regulation. To identify molecules involved in the IFN-gamma response and characterize their modulation, we have isolated genes that are induced following recombinant IFN-gamma treatment of U937 cells, a histiocytic lymphoma cell line with monocytic characteristics. We report here the molecular cloning and characterization of a gene regulated by rIFN-gamma in U937 cells as well as in human mononuclear cells, fibroblasts and endothelial cells. Messenger RNA from this gene is induced within 30 min of rIFN-gamma treatment and demonstrates maximal (greater than 30-fold) accumulation within 5 h. Increased transcription is partly responsible for this accumulation. This gene encodes a protein of relative molecular mass (Mr) 12,378 which has significant amino-acid homology to platelet factor-4 and beta-thromboglobulin, two chemotatic proteins released by platelets on degranulation. This IFN-gamma-inducible protein may be a member of a family of proteins involved in the inflammatory process.
Pure, E., A. D. Luster, et al. (1984). "Cell surface expression of murine, rat, and human Fc receptors by Xenopus oocytes." J Exp Med 160(2): 606-11.
We report that Xenopus laevis oocytes can efficiently translate and insert heterologous membrane receptors into the oocyte plasma membrane, where they can be detected by the binding of either monoclonal antibodies or ligands. Thus, oocytes injected with mRNA from the mouse J774 macrophage-like cell line, the rat RBL-1 basophilic leukemia, and the U937 promonocyte cell line, bound 2.4G2 Fab, rat IgE, and mouse IgG2a, respectively. The increase in the high avidity Fc gamma R observed after gamma-interferon induction of U937 cells was also observed after injection of mRNA from gamma-interferon-induced U937 cells into oocytes. This suggests either much greater message stability or a greater rate of transcription of Fc gamma Rhi mRNA in the gamma-interferon-induced cells. The assay affords a sensitive method for the detection of rare mRNA species that code for plasma membrane proteins.