The T cell-directed CC chemokine TARC is a highly specific biological ligand for CC chemokine receptor 4
The T cell-directed CC chemokine TARC is a highly specific biological ligand for CC chemokine receptor 4
复制标题
DOI：
10.1074/jbc.272.23.15036
复制
发表时间：
1997-06-06
影响因子：
4.8
通讯作者：
Yoshie, O
中科院分区：
文献类型：
--
作者：
Imai, T;Baba, M;Yoshie, O
胸腺和活化调节趋化因子（Thymus and activation-regulated chemokine， TARC）是最近发现的一种CC趋化因子，在胸腺中组成性表达，在受刺激的外周血单个核细胞中短暂表达。TARC作为一种选择性的趋化剂作用于表达一类高亲和力和特异性结合TARC的受体的T细胞。为了鉴定TARC的受体，我们制作了TARC与分泌碱性磷酸酶（SEAP）融合蛋白，并将其用于特异性结合。通过稳定地将5个孤儿受体和5个已知的CC趋化因子受体（CCR1至-5）转染到K562细胞中，我们发现TARC-SEAP选择性地结合到表达CCR4的细胞上。TARC-SEAP也以高亲和力（K-d = 0.5 nM）稳定地结合到表达CCR4的K562细胞上。只有TARC而不是其他五种CC趋化因子（MCP-1（单核细胞趋化蛋白-1），RANTES（激活后调节，正常T细胞表达和分泌），MIP-1 α（巨噬细胞炎症蛋白-1 α）， MIP-1 β和LARC（肝脏和激活调节趋化因子））与TARC- seap结合CCR4。在稳定表达CCR4的293/EBNA-1细胞中，TARC而不是RANTES或MIP-1 α诱导迁移和钙动员。在钙动员实验中，稳定表达CCR4的K562细胞也对TARC有反应。Northern blot分析显示，CCR4 mRNA在人T细胞系和外周血T细胞中表达强烈，但在B细胞、自然杀伤细胞、单核细胞或粒细胞中不表达。综上所述，TARC是CCR4的特异性功能配体，而CCR4是TARC在T细胞上选择性表达的特异性受体。
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-1 alpha (macrophage inflammatory protein-1 alpha), MIP-1 beta, and LARC (liver and activation-regulated chemokine)) competed with TARC-SEAP for binding to CCR4. TARC but not RANTES or MIP-1 alpha 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.