Mackay C R, Beya M F, Matzinger P
Basel Institute for Immunology, Switzerland.
Eur J Immunol. 1989 Aug;19(8):1477-83. doi: 10.1002/eji.1830190820.
The vast majority of T cells in man and mouse use the alpha/beta form of T cell receptor (TcR), and express either CD4 or CD8, whereas the small subset of gamma/delta T cells are usually CD4-CD8-. In contrast to man and mouse, the gamma/delta subset in sheep, defined here using an anti-gamma/delta monoclonal antibody (mAb), comprises 30%-60% of T cells. We show that gamma/delta T cells in sheep express a unique surface molecule termed T19 which is 215 kDa in size and unrelated to either CD45 or the TcR. The T19 molecule was expressed at a distinct stage during gamma/delta T cell ontogeny within the thymus, since gamma/delta thymocytes which appeared early in fetal ontogeny were T19- and also major histocompatibility complex (MHC) class I- and localized almost exclusively to the outer cortex and cortex of the thymus. "Mature-type" gamma/delta thymocytes which emerged late in thymic development were T19+ and MHC class I+ and localized predominantly to the thymic medulla. The sequence of events indicated that these cells were most likely derived from the early gamma/delta thymocytes. These medullary gamma/delta thymocytes showed a very distinctive association with Hassall's corpuscles, suggesting a role for these structures in gamma/delta thymocyte maturation. In the periphery, T19 was expressed exclusively within the gamma/delta T cell subset, however some gamma/delta T cells were T19-. In particular, a large proportion of gamma/delta T cells within intestinal epithelium lacked T19, indicating a correlation between T19 expression and either function or homing patterns of gamma/delta T cells. Both T19+ and T19- gamma/delta T cells were CD2-, and expressed low levels of LFA-1 and CD5. In addition, gamma/delta T cells recirculated differently from other T cells, and appeared not to enter mesenteric lymph nodes at all from the blood. We propose that T19 is a maturation marker for gamma/delta T cells. In addition, the exclusive expression of T19 by gamma/delta T cells indicates that this molecule most likely serves a fundamental role in the interactions and function of gamma/delta T cells.
人和小鼠中的绝大多数T细胞使用α/β形式的T细胞受体（TcR），并表达CD4或CD8，而一小部分γ/δ T细胞通常为CD4-CD8-。与人和小鼠不同，这里使用抗γ/δ单克隆抗体（mAb）定义的绵羊γ/δ亚群占T细胞的30%-60%。我们发现绵羊的γ/δ T细胞表达一种独特的表面分子，称为T19，其大小为215 kDa，与CD45或TcR均无关。T19分子在胸腺内γ/δ T细胞个体发育的一个特定阶段表达，因为在胎儿个体发育早期出现的γ/δ胸腺细胞是T19-，也是主要组织相容性复合体（MHC）I类-，并且几乎完全定位于胸腺的外皮质和皮质。在胸腺发育后期出现的“成熟型”γ/δ胸腺细胞是T19+和MHC I类+，主要定位于胸腺髓质。事件顺序表明这些细胞很可能来源于早期的γ/δ胸腺细胞。这些髓质γ/δ胸腺细胞与哈氏小体有非常独特的关联，表明这些结构在γ/δ胸腺细胞成熟中起作用。在周围组织中，T19仅在γ/δ T细胞亚群中表达，然而一些γ/δ T细胞是T19-。特别是，肠道上皮内的大部分γ/δ T细胞缺乏T19，表明T19表达与γ/δ T细胞的功能或归巢模式之间存在相关性。T19+和T19-γ/δ T细胞均为CD2-，并表达低水平的淋巴细胞功能相关抗原-1（LFA-1）和CD5。此外，γ/δ T细胞的再循环方式与其他T细胞不同，并且似乎根本不从血液进入肠系膜淋巴结。我们提出T19是γ/δ T细胞的成熟标志物。此外，γ/δ T细胞对T19的特异性表达表明该分子很可能在γ/δ T细胞的相互作用和功能中起基本作用。
