Codias E K, Cray C, Baler R D, Levy R B, Malek T R
University of Miami School of Medicine, Department of Microbiology and Immunology, FL 33101.
Immunogenetics. 1989;29(2):98-107. doi: 10.1007/BF00395857.
We have studied the cellular basis for differential expression of the Ly-6A/E alloantigen on T cells obtained from mice of the Ly-6a (10-20% Ly-6A/E+) and Ly-6b (50-60% Ly-6A/E+) haplotypes. During T-cell ontogeny only a small fraction (less than 12%) of thymocytes expressed Ly-6A/E. By 4 weeks of age adult levels of Ly-6A/E bearing lymphocytes were seen in peripheral lymphoid tissue. Immunohistochemical studies of the thymus revealed that Ly-6A/E+ cells were located predominantly in the medulla with small clusters of Ly-6A/E+ cells throughout the cortex. Consistent with this result, phenotypic studies showed that in the adult thymus the majority of Ly-6A/E expression was on mature CD4+CD8- and CD4-CD8+ cortisone-resistant and precursor CD4-CD8- thymocytes. However, a much higher percentage of CD4+CD8- and CD4-CD8- thymocytes as well as CD4+CD8- peripheral T cells expressed Ly-6A/E from Ly-6b mice. Furthermore, although gamma interferon induced increased Ly-6A/E expression in certain thymocyte and T-cell subsets, this induction functioned preferentially for cells obtained from Ly-6b mice. Studies using F1 hybrid mice (Ly-6a x Ly-6b) indicated that the "basal" level of Ly-6A/E expression on these subsets appeared to be under codominant genetic control, whereas gamma interferon-induced regulation of Ly-6A/E expression appeared to be under dominant genetic control. Collectively, these results suggest that the expression of Ly-6A/E on a particular T-cell subset is established in the thymus and is a stable characteristic of each haplotype. In addition, the low levels of Ly-6A/E expression for the Ly-6a haplotype appear to be partially due to the inability of the majority of resting CD4+ T cells to express Ly-6A/E and to the relatively poor induction of this protein by gamma interferon.
我们研究了从Ly-6a单倍型（10-20% Ly-6A/E+）和Ly-6b单倍型（50-60% Ly-6A/E+）小鼠获得的T细胞上Ly-6A/E同种抗原差异表达的细胞基础。在T细胞个体发育过程中，只有一小部分（不到12%）胸腺细胞表达Ly-6A/E。到4周龄时，外周淋巴组织中出现了成年水平的表达Ly-6A/E的淋巴细胞。对胸腺的免疫组织化学研究表明，Ly-6A/E+细胞主要位于髓质，皮质中也有少量Ly-6A/E+细胞簇。与此结果一致，表型研究显示，在成年胸腺中，大多数Ly-6A/E表达于成熟的CD4+CD8-和CD4-CD8+抗可的松的以及前体CD4-CD8-胸腺细胞上。然而，来自Ly-6b小鼠的CD4+CD8-和CD4-CD8-胸腺细胞以及CD4+CD8-外周T细胞中表达Ly-6A/E的比例要高得多。此外，尽管γ干扰素可诱导某些胸腺细胞和T细胞亚群中Ly-6A/E表达增加，但这种诱导作用在来自Ly-6b小鼠的细胞中更为明显。使用F1杂交小鼠（Ly-6a×Ly-6b）的研究表明，这些亚群上Ly-6A/E表达的“基础”水平似乎受共显性遗传控制，而γ干扰素诱导的Ly-6A/E表达调节似乎受显性遗传控制。总的来说，这些结果表明，Ly-6A/E在特定T细胞亚群上的表达在胸腺中确立，并且是每个单倍型的稳定特征。此外，Ly-6a单倍型Ly-6A/E表达水平较低似乎部分是由于大多数静息CD4+T细胞无法表达Ly-6A/E，以及γ干扰素对该蛋白的诱导作用相对较弱。
