TRANSGENIC STUDIES OF TCR REPERTOIRE DIVESIFICATION

免疫系统的主要作用是区分自我 和非我。抗原的特异性识别依赖于 淋巴细胞产生大量克隆受体的能力。 T细胞抗原受体(TCR)的可变区被编码 通过分离的基因片段进行重排和连接 在T细胞发育过程中。T细胞受体的主要来源 多样性存在于基因片段的连接和随机位置 连接核苷酸的添加。后一种过程出现了 与末端脱氧核苷酸转移酶(TDT)不谋而合 活动，尽管TDT的贡献尚未正式确定 在活体内得到了证实。控制T细胞受体谱系是必不可少的 以预防自身免疫性疾病。尽管阿尔法-β-T细胞 在胸腺中受到选择；伽马三角洲T细胞的位置 选拔仍然是一个严密调查的主题。在小鼠期间 胎儿的生命，初波的伽马三角洲T细胞前体表达 有限的连接多样性和精选的生殖系谱系。成虫 树突状表皮细胞(DEC)具有类似的生殖系TCR谱系 而且也表现出很少的连接多样性。在这项研究中，我们建议 建立在胎儿时期高水平表达TdT的转基因小鼠 生活。通过对该区伽马三角洲TCR重排的序列分析 胎儿胸腺细胞，我们将测试不适当的TDT的影响 活体对N区多样性产生的影响。穿过 检查成人DEC细胞，我们将确定是否有 在这个T细胞亚群中发现的几乎单态的T细胞受体是 正向选择的结果，或者仅仅是因为它们是从 胎儿胸腺细胞同样不能表现出连接的多样性。 这些研究不仅应该阐明控制 T细胞抗原受体谱系的多样化，但在 未来将允许我们测试不正常的多元化的影响 γ-βT细胞的发育及其他 自身免疫性疾病的小鼠模型。

The primary role of the immune system is to discriminate between self and non-self. Specific recognition of antigen is dependent on the ability of lymphocytes to generate a wide array of clonal receptors. The variable regions of the T cell antigen receptors (TCR) are encoded by separated gene segments which undergo rearrangement and joining during T cell development. The major source of T cell receptor diversity resides at the site of gene segment joining and random addition of junctional nucleotides. This latter process appears coincidentally with terminal deoxynucleotidyl transferase (TdT) activity, although the contribution of TdT has not yet been formally proven in vivo. Control of the T cell receptor repertoire is essential to the prevention of autoimmune disease. Although alpha beta T cells are subjected to selection in the thymus; the site of gamma delta T cell selection is still a subject of intense investigation. During murine fetal life, initial waves of gamma delta T cell precursors express limited junctional diversity and a selected germline repertoire. Adult dendritic epidermal cells (DEC) bear a similar germline TCR repertoire and also express little junctional diversity. In this study, we propose to create transgenic mice which express TdT at high levels during fetal life. Through sequence analysis of gamma delta TCR rearrangements in fetal thymocytes, we will test the influence of inappropriate TdT activity on the generation of N region diversity in vivo. Through examination of adult DEC cells, we will determine whether or not the virtually monomorphic T cell receptors found in this T cell subset is the result of positive selection, or simply due to their derivation from fetal thymocytes which similarly fail to exhibit junctional diversity. These studies should not only shed light on the mechanisms which control diversification of the T cell antigen receptor repertoire, but in the future will allow us to test the effect of abnormal diversification of the repertoire on the development of gamma beta T cells and in other mouse models of autoimmune disease.