The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
Philip M Murphy - One of the best experts on this subject based on the ideXlab platform.
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CC Chemokine Receptors
xPharm: The Comprehensive Pharmacology Reference, 2008Co-Authors: Philip M MurphyAbstract:There are ten CC Chemokine receptor subtypes, the largest subdivision of the Chemokine superfamily. These Receptors are all coupled to Gi, are highly differentially expressed on most leukocyte subsets, and mediate different types of immune responses. …
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CC Chemokine Receptors 1 and 3 are differentially regulated by il 5 during maturation of eosinophilic hl 60 cells
Journal of Immunology, 1998Co-Authors: H L Tiffany, G Alkhatib, Christophe Combadiere, Edward A Berger, Philip M MurphyAbstract:CC Chemokine Receptors 1 and 3 (CCR1 and CCR3) are expressed by eosinophils; however, factors regulating their expression and function have not previously been defined. Here we analyze Chemokine receptor expression and function during eosinophil differentiation, using the eosinophilic cell line HL-60 clone 15 as a model system. RNA for CCR1, -3, -4, and -5 was not detectable in the parental cells, and the cells did not specifically bind CC Chemokines. Cells treated with butyric acid acquired eosinophil characteristics; expressed mRNA for CCR1 and CCR3, but not for CCR4 or CCR5; acquired specific binding sites for macrophage-inflammatory protein-1α and eotaxin (the selective ligands for CCR1 and CCR3, respectively); and exhibited specific calcium flux and chemotaxis responses to macrophage-inflammatory protein-1α, eotaxin, and other known CCR1 and CCR3 agonists. CCR3 was expressed later and at lower levels than CCR1 and could be further induced by IL-5, whereas IL-5 had little or no effect on CCR1 expression. Consistent with the HIV-1 coreceptor activity of CCR3, HL-60 clone 15 cells induced with butyric acid and IL-5 fused with HeLa cells expressing CCR3-tropic HIV-1 envelope glycoproteins, and fusion was blocked specifically by eotaxin or an anti-CCR3 mAb. These data suggest that CCR1 and CCR3 are markers of late eosinophil differentiation that are differentially regulated by IL-5 in this model.
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molecular cloning of leukotactin 1 a novel human beta Chemokine a chemoattractant for neutrophils monocytes and lymphocytes and a potent agonist at CC Chemokine Receptors 1 and 3
Journal of Immunology, 1997Co-Authors: Byung S Youn, Philip M Murphy, Massimo Locati, Shang M Zhang, Doo H Park, Hal E Broxmeyer, James E Pease, Kathleen Antol, Byoung S KwonAbstract:A new member of human beta-Chemokine cDNA was isolated and named leukotactin-1 (Lkn-1). Lkn-1, along with murine macrophage inflammatory protein-related protein-1 and -2, defines a subgroup of beta-Chemokines based on two conserved cysteines in addition to the four others conserved in all beta-Chemokines. The putative mature Lkn-1 is composed of 92 amino acids with a calculated m.w. of 10,162. The Lkn-1 gene was mapped to human chromosome 17, region q12. Recombinant Lkn-1 was a potent chemoattractant for neutrophils, monocytes, and lymphocytes and induced calcium flux in these cells. Lkn-1 specifically induced calcium flux in CCR1- and CCR3-expressing HOS cell lines. Lkn-1 suppressed colony formation by human granulocyte-macrophage, erythroid, and multipotential progenitor cells stimulated by combinations of growth factors. Hence, we have isolated and characterized a human C6 beta-Chemokine that is a potent agonist at CCR1 and CCR3 and shows broad biologic activities, including leukocyte chemoattraction.
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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
Journal of Immunology, 1996Co-Authors: Eduardo A Garciazepeda, Christophe Combadiere, Philip M Murphy, Marc E Rothenberg, Mindy N Sarafi, F Lavigne, Qutayba Hamid, Andrew D LusterAbstract: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.
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monocyte chemoattractant protein 3 is a functional ligand for CC Chemokine Receptors 1 and 2b
Journal of Biological Chemistry, 1995Co-Authors: Christophe Combadiere, Jo Van Damme, Sunil K Ahuja, Lee H Tiffany, Philip M MurphyAbstract:Abstract The CC Chemokine monocyte chemoattractant protein-3 (MCP-3) activates human monocytes, lymphocytes, basophils, and eosinophils. MCP-3 has been reported to induce [Ca] changes in cells transfected with the monocyte-selective MCP-1 receptor 2B (CC CKR2B) and competes for I-MCP-1 binding on CC CKR2B, suggesting that it may mediate monocyte responses to MCP-3. However, we now show that MCP-3 is a ligand and potent agonist for the macrophage inflammatory protein-1α (MIP-1α)/regulated on activation, normal T expressed, and secreted protein (RANTES) receptor CC CKR1 (rank order for [Ca] changes = MIP-1α > MCP-3 > RANTES), which is expressed in monocytes > neutrophils > eosinophils. I-MCP-3 bound directly to CC CKR1 and CC CKR2B (K = 8 and 7 nM, respectively). Binding to CC CKR1 was competed by all CC Chemokines tested except MCP-1. In contrast, binding to CC CKR2B was competed only by MCP-3 and MCP-1. Both MCP-1 and MCP-3 were equipotent agonists (EC = 10 nM for [Ca] changes). Thus, MCP-3 is a functional ligand for both CC CKR1 and CC CKR2B, which otherwise have distinct selectivities for CC Chemokines. These data suggest that monocyte responses to MCP-3 could be mediated by both CC CKR2B and CC CKR1, whereas eosinophil responses to MCP-3 could be mediated by CC CKR1.
Bernhard Moser - One of the best experts on this subject based on the ideXlab platform.
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Chemokine receptor specific for ip10 and mig structure function and expression in activated t lymphocytes
Journal of Experimental Medicine, 1996Co-Authors: Marcel Loetscher, Marco Baggiolini, Pius Loetscher, B Gerber, Simon Arnett Jones, Luca Piali, I Clarklewis, Bernhard MoserAbstract:A human receptor that is selective for the CXC Chemokines IP10 and Mig was cloned and characterized. The receptor cDNA has an open reading frame of 1104-bp encoding a protein of 368 amino acids with a molecular mass of 40,659 dalton. The sequence includes seven putative transmembrane segments characteristic of G-protein coupled Receptors. It shares 40.9 and 40.3% identical amino acids with the two IL-8 Receptors, and 34.2-36.9% identity with the five known CC Chemokine Receptors. The IP10/Mig receptor is highly expressed in IL-2-activated T lymphocytes, but is not detectable in resting T lymphocytes. B lymphocytes, monocytes and granulocytes. It mediates Ca2+ mobilization and chemotaxis in response to IP10 and Mig, but does not recognize the CXC-Chemokines IL-8, GRO alpha, NAP-2, GCP-2. ENA78, PF4, the CC-Chemokines MCP-1, MCP-2, MCP-3, MCP-4, MIP-1 alpha, MIP-1 beta. RANTES, 1309, eotaxin, nor lymphotactin. The exclusive expression in activated T-lymphocytes is of high interest since the Receptors for Chemokines which have been shown so far to attract lymphocytes, e.g., MCP-1, MCP-2, MCP-3, MIP-1 alpha, MIP-1 beta, and RANTES, are also found in monocytes and granulocytes. The present observations suggest that the IP10/Mig receptor is involved in the selective recruitment of effector T cells.
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interleukin 2 regulates CC Chemokine receptor expression and chemotactic responsiveness in t lymphocytes
Journal of Experimental Medicine, 1996Co-Authors: Pius Loetscher, Marco Baggiolini, Michael Seitz, Bernhard MoserAbstract:Several studies have shown that CC Chemokines attract T lymphocytes, and that CD45RO+, memory phenotype cells are considered to be the main responders. The results, however, have often been contradictory and the role of lymphocyte activation and proliferation has remained unclear. Using CD45RO+ blood lymphocytes cultured under different stimulatory conditions, we have now studied chemotaxis as well as Chemokine receptor expression. Expression of the RANTES/MIP-1 alpha receptor (CC-CKR1) and the MCP-1 receptor (CC-CKR2) was highly correlated with migration toward RANTES, MCP-1, and other CC Chemokines, and was strictly dependent on the presence of IL-2 in the culture medium. Migration and receptor expression were rapidly downregulated when IL-2 was withdrawn, but were fully restored when IL-2 was added again. The effect of IL-2 could be partially mimicked by IL-4, IL-10, or IL-12, but not by IL-13, IFN gamma, IL-1 beta, TNF-alpha, or by exposure to anti-CD3, anti-CD28 or phytohemagglutinin. Activation of fully responsive lymphocytes through the TCR/CD3 complex and CD28 antigen actually had the opposite effect. It rapidly downregulated receptor expression and consequent migration even in the presence of IL-2. In contrast to the effects on CC Chemokine Receptors, stimulation of CD45RO+ T lymphocytes with IL-2 neither induced the expression of the CXC Chemokine Receptors, IL8-R1 and IL8-R2, nor chemotaxis to IL-8. The prominent role of IL-2 in CC Chemokine responsiveness of lymphocytes suggests that IL-2-mediated expansion is a prerequisite for the recruitment of antigen-activated T cells into sites of immune and inflammatory reactions.
Je Sang Ko - One of the best experts on this subject based on the ideXlab platform.
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Human LZIP induces monocyte CC Chemokine receptor 2 expression leading to enhancement of monocyte chemoattractant protein 1/CCL2-induced cell migration
Experimental and Molecular Medicine, 2008Co-Authors: Ho Joong Sung, Hyereen Kang, Je Sang KoAbstract:Chemokines and Chemokine Receptors play a role in migration of circulating leukocytes to the region of inflammation. Human LZIP is an uncharacterized transcription factor and is known to participate in leukotactin (Lkn)-1/CCL15-induced cell migration. We investigated the role of human LZIP in expression of CC Chemokine Receptors (CCRs) and its involvement in monocyte migration. RNase protection analysis showed that LZIP increased mRNA expression of CCR2 and CCR1 in THP-1 cells. Surface expressions of both CCR2 and CCR1 were also increased by LZIP. Results from an electrophoretic mobility shift assay showed that LZIP binds to the C/EBP element in the CCR2 promoter. LZIP also enhanced the chemotactic activities of monocyte chemoattractant protein-1/CCL2 and Lkn-1. These results suggest that LZIP regulates expression of Chemokine Receptors that are involved in monocyte migration.
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differential regulation of CC Chemokine Receptors by 9 cis retinoic acid in the human mast cell line hmc 1
Life Sciences, 2006Co-Authors: Je Sang KoAbstract:Abstract Mast cells are well known as effector cells in a variety of inflammatory diseases, including asthma as well as other allergic disorders. The precise role of 9-cis retinoic acid (9CRA) in mast cells is not understood despite the aCCepted fact that 9CRA regulates inflammatory responses and neutrophil differentiation. In this study, we investigated the effects of 9CRA on the expression of CC Chemokine Receptors in the human mast cell line, HMC-1. 9CRA selectively inhibits the CCR2 mRNA level and increases the CCR3 mRNA level in both a time and dose dependent manner. Other CC Chemokine Receptors, including CCR1, CCR4 and CCR5 are not altered by treatment with 9CRA. Both TNF-α and LPS, known pro-inflammatory molecules, have no effect on mRNA levels of CC Chemokine Receptors. For surface expression, 9CRA decreased the CCR2 level but had no effect on the CCR3 level. 9CRA inhibited the chemotactic activity in response to the CCR2-dependent Chemokine, MCP-1/CCL2 but not in response to CCR3-specific Chemokine, eotaxin/CCL11. 9CRA decreased spontaneous homotype clustering. Therefore, our results demonstrate that 9CRA differentially decreases both CCR2 expression and chemotactic ability of HMC-1 cells, and may regulate the inflammatory effects of mast cells.
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differential effects of 9 cis retinoic acid on expression of CC Chemokine Receptors in human monocytes
Biochemical Pharmacology, 2004Co-Authors: Sung Wuk Jang, Ho Joong Sung, Doe Sun Na, Je Sang KoAbstract:Abstract 9- cis Retinoic acid (9-CRA) is a lipophilic molecule that binds to the retinoid X receptor (RXR). Although retinoic acid (RA) has been known to regulate neutrophil differentiation, a specific role for 9-CRA in Chemokine-mediated cellular processes remains obscure. We investigated the effects of 9-CRA on expression of CC Chemokine Receptors (CCRs) in human monocytic THP-1 cells and peripheral blood monocytes. RNase protection assay was performed to examine the mRNA levels of CCRs in 9-CRA-treated THP-1 cells. mRNA expression of CCR1 and CCR2 was induced in both a dose and time dependent manner. CCR1 and CCR2 mRNA expression began to increase from 6 h after a 100 nM 9-CRA treatment and reached a maximal level at 12 h. Surface expression of CCRs was monitored by flow cytometry. CCR1 and CCR2 surface expression increased in 9-CRA-treated THP-1 cells, but not in untreated cells. Calcium mobilization and chemotactic activity were determined to examine the effect of 9-CRA on cell movement. The intracellular Ca 2+ concentration and the chemotactic activity increased in 9-CRA-treated cells in response to the CCR1-dependent Chemokines Lkn-1, MIP-1α, and RANTES, and the CCR2-specific Chemokine MCP-1. Increased surface expression of CCR1 and the Ca 2+ influx due to 9-CRA were confirmed in peripheral blood monocytes. Taken together, 9-CRA increases the expression levels of mRNA and protein of both CCR1 and CCR2, and the cell migration ability in THP-1 cells and peripheral blood monocytes, indicating that 9-CRA may regulate inflammatory processes through an increased response to CCR1- and CCR2-dependent Chemokines.
Osamu Yoshie - One of the best experts on this subject based on the ideXlab platform.
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Chemokine Receptors in human basophils: inducible expression of functional CXCR4
Journal of Leukocyte Biology, 2001Co-Authors: Motoyasu Iikura, Kouji Matsushima, Motoji Kitaura, Misato Miyamasu, Masao Yamaguchi, Osamu Yoshie, Yutaka Morita, Hiroshi Kawasaki, Kazuhiko Yamamoto, Koichi HiraiAbstract:We examined the expression profile of Chemokine Receptors in human basophils and their regulation by cytokines. Basophils expressed tran- scripts of CC Chemokine Receptors (CCR)1, CCR2, CCR3, and CCR5 and CXC Chemokine Receptors (CXCR)1, CXCR2, and CXCR4. In contrast to the other Receptors, surface-CXCR4 expression was not detected in fresh- and whole-blood basophils, but it became apparent gradually during incuba- tion. Among 16 Chemokines tested, eotaxin in- duced the most potent basophil migration. SDF-1 also induced a strong, migratory response compa- rable with that induced by eotaxin in 24-h, cul- tured basophils, but it failed to induce degranula- tion. IL-3 abrogated CXCR4 expression com- pletely, and it only down-regulated CCR2 and CCR3 expression slightly. IL-5, GM-CSF, and IL-4 also down-regulated CXCR4 expression. Thus, ex- pression of CXCR4 was the most strongly affected by cytokines, and this may represent an alternative mechanism for control of cell-specific, biological responses to SDF-1. J. Leukoc. Biol. 70: 113-120; 2001.
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cutting edge differential regulation of Chemokine Receptors during dendritic cell maturation a model for their trafficking properties
Journal of Immunology, 1998Co-Authors: Silvano Sozzani, Osamu Yoshie, Paola Allavena, Giovanna Damico, Walter Luini, Giancarlo Bianchi, Motoji Kataura, Toshio Imai, Raffaella Bonecchi, Alberto MantovaniAbstract:Upon exposure to immune or inflammatory stimuli, dendritic cells (DC) migrate from peripheral tissues to lymphoid organs, where they present Ag. CC Chemokines induce chemotactic and transendothelial migration of immature DC, in vitro. Maturation of DC by CD40L, or by LPS, IL-1, and TNF, induces down-regulation of the two main CC Chemokine Receptors expressed by these cells, CCR1 and CCR5, and abrogates chemotaxis to their ligands. Inhibition was rapid (<1 h) and included the unrelated agent FMLP. Concomitantly, the expression of CCR7 and the migration to its ligand EBI1 ligand Chemokine (ELC)/macrophage inflammatory protein (MIP)-3β, a Chemokine expressed in lymphoid organs, were strongly up-regulated, though with slower kinetics (24–48 h). Rapid inhibition of responsiveness to chemoattractants present at sites of inflammation and immune reaction may be permissive for leaving peripheral tissues. Conversely, the slower acquisition of responsiveness to ELC/MIP-3β may guide subsequent localization of DC in lymphoid organs.
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Macrophage-derived Chemokine is a functional ligand for the CC Chemokine receptor 4.
Journal of Biological Chemistry, 1998Co-Authors: Toshio Imai, Osamu Yoshie, Miyuki Nishimura, David Chantry, Carol J. Raport, Christi L. Wood, Ronald Godiska, Patrick W. GrayAbstract:Abstract Macrophage-derived Chemokine (MDC) is a recently identified member of the CC Chemokine family. MDC is not closely related to other Chemokines, sharing most similarity with thymus- and activation-regulated Chemokine (TARC), which contains 37% identical amino acids. Both Chemokines are highly expressed in the thymus, with little expression seen in other tissues. In addition, the genes for MDC and TARC are encoded by human chromosome 16. To explore this relationship in greater detail, we have more precisely localized the MDC gene to chromosome 16q13, the same position reported for the TARC gene. We have also examined the interaction of MDC with CC Chemokine receptor 4 (CCR4), recently shown to be a receptor for TARC. Using a fusion protein of MDC with secreted alkaline phosphatase, we observed high affinity binding of MDC-secreted alkaline phosphatase to CCR4-transfected L1.2 cells (K d = 0.18 nm). MDC and TARC competed for binding to CCR4, while no binding competition was observed for six other Chemokines (MCP-1, MCP-3, MCP-4, RANTES (regulated on activation normal T cell expressed and secreted), macrophage inflammatory protein-1α, macrophage inflammatory protein-1β). MDC was tested for calcium mobilization in L1.2 cells tranfected with seven different CC Chemokine Receptors. MDC induced a calcium flux in CCR4-transfected cells, but other Receptors did not respond to MDC. TARC, which also induced calcium mobilization in CCR4 transfectants, was unable to desensitize the response to MDC. In contrast, MDC fully desensitized a subsequent response to TARC. Both MDC and TARC functioned as chemoattractants for CCR4 transfectants, confirming that MDC is also a functional ligand for CCR4. Since MDC and TARC are both expressed in the thymus, one role for these Chemokines may be to attract CCR4-bearing thymocytes in the process of T cell education and differentiation.
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the t cell directed CC Chemokine tarc is a highly specific biological ligand for CC Chemokine receptor 4
Journal of Biological Chemistry, 1997Co-Authors: Toshio Imai, Masataka Baba, Miyuki Nishimura, Mayumi Kakizaki, Shin Takagi, Osamu YoshieAbstract:Abstract Thymus and activation-regulated Chemokine (TARC) is a recently identified CC Chemokine that is expressed constitutively in thymus and transiently in stimulated peripheral blood mononuclear cells. TARC functions as a selective chemoattractant for T cells that express a class of Receptors binding TARC with high affinity and specificity. To identify the receptor for TARC, we produced TARC as a fusion protein with secreted alkaline phosphatase (SEAP) and used it for specific binding. By stably transfecting five orphan Receptors and five known CC Chemokine Receptors (CCR1 to -5) into K562 cells, we found that TARC-SEAP bound selectively to cells expressing CCR4. TARC-SEAP also bound to K562 cells stably expressing CCR4 with a high affinity (K d = 0.5 nm). Only TARC and not five other CC Chemokines (MCP-1 (monocyte chemoattractant protein-1), RANTES (regulated upon activation, normal T cells expressed and secreted), MIP-1α (macrophage inflammatory protein-1α), MIP-1β, and LARC (liver and activation-regulated Chemokine)) competed with TARC-SEAP for binding to CCR4. TARC but not RANTES or MIP-1α induced migration and calcium mobilization in 293/EBNA-1 cells stably expressing CCR4. K562 cells stably expressing CCR4 also responded to TARC in a calcium mobilization assay. Northern blot analysis revealed that CCR4 mRNA was expressed strongly in human T cell lines and peripheral blood T cells but not in B cells, natural killer cells, monocytes, or granulocytes. Taken together, TARC is a specific functional ligand for CCR4, and CCR4 is the specific receptor for TARC selectively expressed on T cells.
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molecular cloning of a novel human CC Chemokine ebi1 ligand Chemokine that is a specific functional ligand for ebi1 CCr7
Journal of Biological Chemistry, 1997Co-Authors: Ryu Yoshida, Motoji Kitaura, Toshio Imai, Masataka Baba, Miyuki Nishimura, Mayumi Kakizaki, Kunio Hieshima, Jun Kusuda, Hisayuki Nomiyama, Osamu YoshieAbstract:Abstract By searching the expressedsequence tag (EST) data base, we identified partial cDNA sequences encoding a novel human CC Chemokine. We determined the complete cDNA sequence that encodes a highly basic polypeptide of a total 98 amino acids with 20 to 30% identity to other human CC Chemokines. We termed this novel Chemokine fromEBI1-Ligand Chemokine as ELC (see below). The ELC mRNA was most strongly expressed in the thymus and lymph nodes. Recombinant ELC protein was expressed as a fusion protein with the Flag tag (ELC-Flag). For receptor-binding assays, recombinant ELC protein fused with the secreted form of alkaline phosphatase (SEAP) was used. By stably expressing five CC Chemokine Receptors (CCR1 to 5) and five orphan Receptors, ELC-SEAP was found to bind specifically to an orphan receptor EBI1. Only ELC-Flag, but not MCP-1, MCP-2, MCP-3, eotaxin, MIP-1α, MIP-1β, RANTES (regulated on activation normal T cell expressed and secreted), thymus and activation-regulated Chemokine (TARC), or liver and activation-regulated Chemokine (LARC), competed with ELC-SEAP for EBI1. ELC-Flag-induced transient calcium mobilization and chemotactic responses in EBI1-transfected cells. ELC-Flag also induced chemotaxis in HUT78 cells expressing endogenous EBI1 at high levels. By somatic hybrid and radiation hybrid analyses, the gene for ELC (SCYA19) was mapped to chromosome 9p13 instead of chromosome 17q11.2 where the genes for CC Chemokines are clustered. Taken together, ELC is a highly specific ligand for EBI1, which is known to be expressed in activated B and T lymphocytes and strongly up-regulated in B cells infected with Epstein-Barr virus and T cells infected with herpesvirus 6 or 7. ELC and EBI1 may thus play roles in migration and homing of normal lymphocytes, as well as in pathophysiology of lymphocytes infected with these herpesviruses. We propose EBI1 to be designated as CCR7.
Byoung S Kwon - One of the best experts on this subject based on the ideXlab platform.
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truncation of nh2 terminal amino acid residues increases agonistic potency of leukotactin 1 on CC Chemokine Receptors 1 and 3
Journal of Biological Chemistry, 2002Co-Authors: Kyubum Kwack, Doe Sun Na, Byoung S KwonAbstract:Abstract Leukotactin-1 (Lkn-1) is a human CC Chemokine that binds to both CC Chemokine receptor 1 (CCR1) and CCR3. Structurally, Lkn-1 is distinct from other human CC Chemokines in that it has long amino acid residues preceding the first cysteine at the NH2 terminus, and contains two extra cysteines. NH2-terminal amino acids of Lkn-1 were deleted serially, and the effects of each deletion were investigated. In CCR1-expressing cells, serial deletion up to 20 amino acids (Δ20) did not change the calcium flux-inducing activity significantly. Deletion of 24 amino acids (Δ24), however, increased the agonistic potency ∼100-fold. Deletion of 27 or 28 amino acids also increased the agonistic potency to the same level shown by Δ24. Deletion of 29 amino acids, however, abolished the agonistic activity almost completely showing that at least 3 amino acid residues preceding the first cysteine at the NH2 terminus are essential for the biological activity of Lkn-1. Loss of agonistic activity was due to impaired binding to CCR1. In CCR3-expressing cells, Δ24 was the only form of Lkn-1 mutants that revealed increased agonistic potency. Our results indicate that posttranslational modification is a potential mechanism for the regulation of biological activity of Lkn-1.
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molecular cloning of leukotactin 1 a novel human beta Chemokine a chemoattractant for neutrophils monocytes and lymphocytes and a potent agonist at CC Chemokine Receptors 1 and 3
Journal of Immunology, 1997Co-Authors: Byung S Youn, Philip M Murphy, Massimo Locati, Shang M Zhang, Doo H Park, Hal E Broxmeyer, James E Pease, Kathleen Antol, Byoung S KwonAbstract:A new member of human beta-Chemokine cDNA was isolated and named leukotactin-1 (Lkn-1). Lkn-1, along with murine macrophage inflammatory protein-related protein-1 and -2, defines a subgroup of beta-Chemokines based on two conserved cysteines in addition to the four others conserved in all beta-Chemokines. The putative mature Lkn-1 is composed of 92 amino acids with a calculated m.w. of 10,162. The Lkn-1 gene was mapped to human chromosome 17, region q12. Recombinant Lkn-1 was a potent chemoattractant for neutrophils, monocytes, and lymphocytes and induced calcium flux in these cells. Lkn-1 specifically induced calcium flux in CCR1- and CCR3-expressing HOS cell lines. Lkn-1 suppressed colony formation by human granulocyte-macrophage, erythroid, and multipotential progenitor cells stimulated by combinations of growth factors. Hence, we have isolated and characterized a human C6 beta-Chemokine that is a potent agonist at CCR1 and CCR3 and shows broad biologic activities, including leukocyte chemoattraction.