Macrophage-derived chemokine is localized to thymic medullary epithelial cells and is a chemoattractant for CD3(+), CD4(+), CD8(low) thymocytes.
Macrophage-derived chemokine is localized to thymic medullary epithelial cells and is a chemoattractant for CD3(+), CD4(+), CD8(low) thymocytes.
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巨噬细胞衍生的趋化因子定位于胸腺髓质上皮细胞，是 CD3( )、CD4( )、CD8(低) 胸腺细胞的趋化剂。
作者：
D. Chantry;P. Romagnani;C. Raport;C. Wood;A. Epp;S. Romagnani;P. Gray
巨噬细胞源性趋化因子（MDC）是最近鉴定的CC趋化因子，其是树突状细胞、自然杀伤（NK）细胞和外周血T细胞的Th 2亚群的有效化学引诱物。在正常组织中，MDC mRNA主要在胸腺中表达。免疫组织化学分析5人出生后胸腺表现出高MDC免疫反应性，这是选择性地定位于髓质内的上皮细胞。为了研究MDC对未成熟T细胞的影响，我们鉴定了小鼠和大鼠MDC的cDNA克隆。MDC在小鼠组织中的表达也受到高度限制，仅在胸腺中发现显著水平的mRNA。胸腺细胞表达MDC的高亲和力结合位点（kd = 0.7 nmol/L），并且在体外，MDC是这些细胞的化学引诱物。MDC反应性小鼠胸腺细胞表达CCR 4的mRNA，CCR 4是最近鉴定的MDC受体。MDC应答细胞的表型分析显示，它们富集了表达高水平的CD 3和CD 4并且具有降低水平的CD 8的双阳性细胞的子集。MDC反应细胞的这一亚群与髓质内观察到的MDC表达一致，因为在那里发现了更多的成熟细胞。因此，MDC可能在胸腺内发育期间T细胞亚群的迁移中发挥作用。
Macrophage-derived chemokine (MDC) is a recently identified CC chemokine that is a potent chemoattractant for dendritic cells, natural killer (NK) cells, and the Th2 subset of peripheral blood T cells. In normal tissues, MDC mRNA is expressed principally in the thymus. Immunohistochemical analysis performed on 5 human postnatal thymuses showed high MDC immunoreactivity, which was selectively localized to epithelial cells within the medulla. To examine the effects of MDC on immature T cells, we have identified cDNA clones for mouse and rat MDC. Expression of MDC in murine tissues is also highly restricted, with significant levels of mRNA found only in the thymus. Thymocytes express high-affinity binding sites for MDC (kd = 0.7 nmol/L), and, in vitro, MDC is a chemoattractant for these cells. MDC-responsive murine thymocytes express mRNA for CCR4, a recently identified receptor for MDC. Phenotypic analysis of MDC-responsive cells shows that they are enriched for a subset of double-positive cells that express high levels of CD3 and CD4 and that have reduced levels of CD8. This subset of MDC-responsive cells is consistent with the observed expression of MDC within the medulla, because more mature cells are found there. MDC may therefore play a role in the migration of T-cell subsets during development within the thymus.