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Query: UNIPROT:P10145 (IL-8)
 23,849 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chemokines are pro-inflammatory molecules with a diverse array of biological and biochemical functions. These molecules induce the migration of a number of leukocyte subsets including monocytes, neutrophils, and T-cells. The recent cloning of the IL-8, GRO, and MIP-1 alpha chemokine receptors revealed that these glycoproteins belong to the serpentine family of seven transmembrane G-protein-coupled receptors. Other members of this family include the chemotactic receptors for fMLP and C5a, indicating that a common pathway for eliciting the directional migration of leukocytes is probably transduced via G proteins. Ligand binding to chemokine receptors is complex, featured by multiple chemokines binding to a single receptor and multiple receptors binding a specific ligand. Future directions in this field appear to be focused on the cloning of novel receptors and the identification of ligands for orphaned receptors.
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PMID:Chemokines and serpentines: the molecular biology of chemokine receptors. 824 14

The mixed lymphocyte reaction (MLR) has previously been used to elucidate pathways of cytokine activation and T-lymphocyte proliferation and is regarded as a model that simulates responses in allograft rejection. Studies have indicated that interleukin-1 (IL-1), a potent inflammatory cytokine, may have an important activating role in the MLR response. The discovery of a naturally occurring IL-1 receptor antagonist protein (IRAP) has renewed interest in control of IL-1--dependent responses both in vitro and in vivo. MLR cultures were used to study the role of IL-1 and IRAP in the regulation of subsequent cytokines during a T-lymphocyte-mediated alloantigen response. The temporal expression of IL-1 and IRAP during 5-day one-way MLR assays suggested antagonistic production of the two cytokines. IL-1 was produced early in the response, peaking at 4 hours through day 2, subsequently declining to near-background levels on day 5 of culture. In contrast, production of IRAP was delayed until day 2, steadily increased on days 3 and 4, and peaked on day 5 of culture, which correlated with the declining levels of IL-1. The addition of graded doses of IRAP (25 to 1,000 ng/mL) to MLR cultures decreased IL-1 production but had no effect on T-lymphocyte proliferative response. In addition, IRAP had little effect on the production of either IL-2 or tumor necrosis factor. The addition of 25 ng/mL of IRAP to MLR assays showed significantly decreased levels of two potent chemotactic cytokines, IL-8 and macrophage inflammatory protein-1 alpha (MIP-1 alpha), at peak chemokine production on day 5 of culture. The levels of IL-8 and MIP-1 alpha could be restored by the addition of IL-1 to the IRAP-treated cultures. IL-8 and MIP-1 alpha represent the two different families of chemotactic cytokines, C-X-C (IL-8) and C-C (MIP-1 alpha), and potentially play important roles in the recruitment of leukocytes to a site of immune allogeneic response. These studies indicate that regulation of IL-1 by IRAP does not significantly reduce T-lymphocyte activation but can regulate the production of chemokines involved in leukocyte recruitment.
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PMID:Interleukin-1 receptor antagonist blocks chemokine production in the mixed lymphocyte reaction. 826 Jul 4

Rapamycin (RPM) treatment prevents accelerated rejection of cardiac allografts in sensitized rats. The prominent feature of this brisk 24-h rejection, which includes a panoply of both cellular and humoral host immune responses, is a massive infiltration of rejecting grafts with neutrophils. In this study we tested the hypothesis that RPM-mediated therapeutic effects on accelerated rejection may be linked to decreased expression of protein encoded by gro/melanoma-growth stimulatory activity gene (KC) and macrophage inflammatory protein-2 (MIP-2) genes, the operational rat homologues of the human intercrine-alpha cytokines with proinflammatory IL-8-like neutrophil activation/chemotactic properties. The induction of these genes was then correlated with mRNA profiles encoding for Th1-selective IFN-gamma and CTL-specific granzyme B proteins. Northern blot analysis of RNA from cardiac allografts of sensitized untreated recipients, revealed maximal levels of KC and MIP-2 mRNA at 3 to 6 h after transplantation. In contrast, IFN-gamma mRNA, which was at most very weakly expressed at 3 h, peaked between 6 to 12 h. As with IFN-gamma, granzyme B transcripts were undetectable at 3 h, but peaked around the time of actual graft rejection at 24 h. RPM therapy abrogated accelerated rejection and prolonged cardiac allograft survival to ca. 46 days. This effect was associated with markedly reduced expression of KC and MIP-2 mRNA in the first 24 h as well as at 7 and 34 days after transplantation. Moreover, RPM completely blocked intragraft appearance of granzyme B and IFN-gamma mRNA in long term cardiac allografts. Immunohistologic analysis has revealed that accelerated rejection was associated with extensive neutrophil infiltration, which peaked at 18 to 24 h. At this time, leukocytes and endothelium were intensely stained for IL-8 and IFN-gamma antibodies. In contrast, the allografts from RPM-treated hosts showed essentially no neutrophil infiltration and minor, focal staining for IL-8 and IFN-gamma. This study demonstrates an association between the early expression of genes for proinflammatory IL-8-dependent neutrophil chemotactic activity, and later expression of genes associated with activation/effector activity of CTL and NK cells. It also documents a novel effect of RPM in vivo, which results in the suppression of intragraft IL-8-like and CTL-dependent mRNA/protein production and diminished neutrophil infiltration; these may contribute to the striking efficacy of RPM therapy in sensitized graft recipients.
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PMID:Rapamycin treatment depresses intragraft expression of KC/MIP-2, granzyme B, and IFN-gamma in rat recipients of cardiac allografts. 833 97

Macrophage inflammatory protein 1 alpha (MIP-1 alpha) is a potent stem cell inhibitor and a member of a large and expanding family of related cytokines. In an effort to understand the molecular basis of the activities of MIP-1 alpha, we have sought to characterize the cellular receptors for this molecule. Our results demonstrate the presence of abundant MIP-1 alpha receptors on both human and murine cells. The receptor on K562 cells can bind a range of members of the MIP-1 alpha family and may thus be a general MIP-1 alpha family receptor. Murine FDCPmix cells also bind a range of members of this peptide family, although the receptor(s) that they express appear somewhat more selective for peptides capable of displaying stem cell inhibitory properties. The human and murine receptors do not bind members of the related interleukin 8 family of peptides and are thus distinct from the recently cloned interleukin 8 receptor. We suggest that the receptor on the murine cell is a candidate for the receptor responsible for articulating stem cell inhibitory signals following MIP-1 alpha binding.
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PMID:Characterization of a receptor for macrophage inflammatory protein 1 alpha and related proteins on human and murine cells. 838 74

The BLR1 gene, isolated initially from Burkitt's lymphoma cells (Eur. J. Immunol. 1992. 22: 2795), encodes a G protein-coupled receptor with significant relationship to receptors for chemokines (IL-8, MIP-1 alpha) and neuropeptides. The murine homologue of human BLR1 was cloned and used to investigate its expression in vivo. blr1-specific transcripts are observed in secondary lymphatic organs and to a lesser extent in brain of adult mice but not in other tissues. RNA in situ hybridization localizes blr1 transcription to primary follicles and to the mantle zone of secondary follicles. SCID mice in which mature B cell development is severely impaired exhibit a strongly reduced level of blr1-specific RNA in the spleen. The analysis of murine lymphoid tumor cell lines representing distinct stages of the B cell lineage reveals elevated expression of blr1 in B cell lymphomas but not in pre-B lymphomas or plasmacytomas. Induction of differentiation of resting B cells by cytokines or mitogens down-regulates expression of blr1. RNA in situ hybridization using brain sections of adult mice detects blr1 transcription in the granule and Purkinje cell layer of the cerebellum. Interestingly, the blr1 gene is also expressed during late embryogenesis in fetal liver and brain. In view of the remarkable expression pattern in the B cell lineage we suggest that murine BLR1 may represent a cytokine/neuropeptide receptor exerting regulatory functions on recirculating mature B lymphocytes.
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PMID:The G protein-coupled receptor BLR1 is involved in murine B cell differentiation and is also expressed in neuronal tissues. 840 54

Viruses are known to acquire and modify the genes of their hosts to attain a survival advantage in the host environment. Herpesvirus saimiri (HVS) is a T-lymphotropic virus that causes fatal lymphoproliferative diseases in several non-human primates. The gene ECRF3 of HVS was most likely acquired from a primate host. ECRF3 encodes a putative seven-transmembrane-domain receptor that is remotely related (approximately 30% amino acid identity) to the known mammalian alpha and beta chemokine receptors, namely interleukin-8 receptor (IL8R) types A and B and the MIP-1 alpha/RANTES receptor, respectively. Chemokines regulate the trafficking, activation, and, in some cases, proliferation of myeloid and lymphoid cell types. We now show that ECRF3 encodes a functional receptor for the alpha chemokines IL-8, GRO/melanoma growth stimulatory activity (MGSA), and NAP-2 but not for beta chemokines, a specificity identical to that of IL8RB. Paradoxically, IL8RA shares 77% amino acid identity with IL8RB but is not a receptor for GRO/MGSA or NAP-2. This is the first functional characterization of a viral seven-transmembrane-domain receptor. It suggests a novel role for alpha chemokines in the pathogenesis of HVS infection by transmembrane signaling via the product of ECRF3.
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PMID:Molecular piracy of mammalian interleukin-8 receptor type B by herpesvirus saimiri. 840 86

A unique subset of gamma delta T cells, termed dendritic epidermal T cells (DETC), resides in symbiosis with keratinocytes in mouse epidermis. We have shown previously that interleukin 7 (IL-7) which is produced by keratinocytes, promotes growth and prevents apoptosis in DETC. To extend this observation, we examined 12 cytokines, each of which is expressed by epidermal cells at mRNA and/or protein levels, for their capacities to modulate the growth of DETC. Cytokines examined included IL-1 alpha, IL-2, IL-3, IL-4, IL-6, IL-7, IL-8, IL-10, tumor necrosis factor-alpha (TNF alpha), interferon-gamma (IFN gamma), granulocyte/macrophage-colony stimulating factor (GM-CSF), and macrophage inflammatory protein-1 alpha (MIP-1 alpha). When tested individually, IL-2 and IL-7 promoted maximal growth of the long-term cultured DETC line 7-17. When tested in combinations, synergistic growth-promoting effects were seen with IL-2 and IL-4 or IL-7, and with IL-7 and IL-4 or TNF alpha. Dose-response experiments demonstrated that TNF alpha, which is produced by keratinocytes, enhances IL-7-induced DETC proliferation, but inhibits IL-2-induced proliferation. The mouse keratinocyte-derived cell line Pam 212 was used to test these cytokines for their capacities to regulate keratinocyte growth. Only gamma IFN, which is produced by DETC, inhibited proliferation in a dose-dependent fashion. These results illustrate three reciprocal pathways by which epidermal cytokines regulate the growth of epidermal cells: 1) a paracrine mechanism by which keratinocyte-derived cytokines (e.g., IL-7 and TNF alpha) promote the growth of DETC, 2) an autocrine mechanism by which DETC-derived cytokines (e.g., IL-2 and IL-4) support their own growth, and 3) a reciprocal pathway in which a cytokine produced by resident epidermal leukocytes (e.g., gamma IFN) modulates the growth of keratinocytes.
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PMID:Reciprocal cytokine-mediated cellular interactions in mouse epidermis: promotion of gamma delta T-cell growth by IL-7 and TNF alpha and inhibition of keratinocyte growth by gamma IFN. 840 21

Macrophage inflammatory proteins-1 (MIP-1) alpha and beta are members of the C-C branch of the platelet factor 4 superfamily of cytokines, recently designated the "chemokine" superfamily. It has been suggested that the major cellular targets for the biologic activities of the C-C chemokines are the mononuclear leukocytes. However, the original designation of murine MIP-1 proteins as inflammatory mediators was based on suggestions that they activated neutrophil functions such as chemotaxis, the respiratory burst, and degranulation. In this study, we have evaluated the ability of human (Hu) MIP-1 alpha and beta to affect purified human neutrophil function. Although both rHuMIP-1 alpha and -1 beta stimulated significant calcium mobilization in human monocytes, only HuMIP-1 alpha exerted a detectable effect on neutrophils. HuMIP-1 alpha stimulated a small, dose-dependent increase in intracellular calcium, which was accompanied by a simultaneous change in right-angle light scatter, the latter indicating induction of shape change. While the effect of HuMIP-1 alpha on calcium mobilization in neutrophils was small when compared with that elicited by IL-8 or Gro alpha, it had similar characteristics to that by other receptor-dependent neutrophil agonists in that it was dependent on pertussis toxin-sensitive G proteins and on both mobilization of calcium from intracellular sources as well as influx from the extracellular environment. In addition, stimulation of neutrophils with HuMIP-1 alpha led to desensitization to subsequent additions of HuMIP-1 alpha. The stimulatory effect of HuMIP-1 alpha on neutrophil calcium mobilization and shape change was not coupled to other standard measures of neutrophil effector function. For instance, neither HuMIP-1 alpha nor -1 beta had any detectable stimulatory effect on the Na+/H+ antiport, degranulation, actin polymerization, or chemotaxis. Moreover, although HuMIP-1 alpha binding could easily be measured on monocytes or monocytic cell lines, the number of sites were too few to characterize on neutrophils by the same technique. Taken together, these results show that neither HuMIP-1 alpha nor -1 beta stimulate significant neutrophil activation and support the concept that the biologic effects of members of the C-C branch of the platelet factor 4 superfamily are not primarily directed toward neutrophils.
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PMID:Uncoupling of early signal transduction events from effector function in human peripheral blood neutrophils in response to recombinant macrophage inflammatory proteins-1 alpha and -1 beta. 848 47

We present a detailed analysis of cytokine expression patterns of the two permanent human bone marrow stromal cell lines, L87/4 and L88/5. These cell lines, previously established in our laboratory, are highly radiotolerant without cell detachment and support long-term cultures of CD(34+)-enriched human cord blood cells. RT-PCR analysis of 22 different cytokines or cytokine receptor mRNAs showed an almost identical expression pattern in the two stromal cell lines compared to primary human Dexter-type stroma. Since stromal feeder lines employed in long-term cultures usually are irradiated and grown in media containing corticosteroids, we analyzed the impact of irradiation and dexamethasone on cytokine production in the two cell lines by RT-PCR, Northern blot analysis, bioassays, and RIAs. By RT-PCR analysis, constitutive mRNA expression of c-kit, G-CSF, GM-CSF, IL-1 beta, IL-6, IL-7, IL-8, IL-11, Kit ligand (KL), LIF, M-CSF, MIP-1 alpha, TGF-beta, and TNF-alpha was demonstrated in both cell lines, with L87/4 a more potent cytokine producer than L88/5. Northern blot data showed an increase in mRNA levels for GM-CSF, IL-1 beta, and LIF by irradiation and IL-1 alpha treatment in both cell lines. IL-1 alpha-induced GM-CSF, IL-1 beta, IL-6, IL-11, and LIF mRNA levels were reduced by the addition of dexamethasone, whereas dexamethasone had no influence on the amounts of IL-1 alpha-induced G-CSF mRNA. L87/4 and, to a lower extent, L88/5 cells showed dexamethasone-dependent increases in KL mRNA, while KL mRNA levels were not stimulated by IL-1 alpha.
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PMID:Constitutive and modulated cytokine expression in two permanent human bone marrow stromal cell lines. 853 85

The responses of cloned human NK cells (ERNK57) to seven CC chemokines (monocyte chemotactic protein-1 (MCP-1), MCP-2, MCP-3, RANTES (regulated on activation, normal T cell expressed and secreted), macrophage inflammatory protein-1 alpha (MIP-1 alpha), MIP-1 beta, and 1309) and two CXC chemokines (IL-8 and IP-10) were studied. Except for 1309, all CC chemokines induced chemotaxis of the NK cells in vitro, whereas the CXC chemokines were inactive. Maximal activity was obtained at 1 nM for MCP-1 and 10 to 100 nM for the other CC chemokines. The response showed a typically bimodal concentration dependence in all cases, except for RANTES, which induced a linear increase of migration over the concentration range of 0.1 to 1000 nM. A transient rise of the cytosolic-free Ca2+ concentration ([Ca2+]i), which is characteristic for chemokine-stimulated leukocytes, was observed in NK cells after stimulation with all six active chemokines. Since granule exocytosis is required for NK cell-dependent target killing, the effect of CC chemokines on exocytosis was tested. All CC chemokines that induced chemotaxis and [Ca2+]i changes also induced the release of granzyme A and N-acetyl-beta-D-glucosaminidase from cloned and blood NK cells, as well as CD8+ T cells after pretreatment with cytochalasin B. Maximum release was obtained from NK cells, and amounted to 35% and 13% of the total content of granzyme A and N-acetyl-beta-D-glucosaminidase, respectively. The capacity of cloned NK cells and CD8+ T cells to respond to chemokines depended on the time in culture after stimulation with PHA in the presence of irradiated feeder cells, and maximum responses were observed after 10 to 16 days. Our results demonstrate that CC chemokines activate NK cells, and are, therefore, not only attractants for monocytes, T lymphocytes, and eosinophil and basophil granulocytes.
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PMID:Activation of NK cells by CC chemokines. Chemotaxis, Ca2+ mobilization, and enzyme release. 859 80


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