TRANSGENIC STUDIES OF TCR REPERTOIRE DIVESIFICATION

TCR 库多样化的转基因研究

• 批准号: 3769941
• 负责人: HARRY W SCHROEDER
• 金额: --
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3769941
• 关键词: T cell receptor; antigen receptors; autoimmune disorder; embryo /fetus cell /tissue; enzyme activity; gene expression; genetic regulation; genetic transcription; genetically modified animals; genotype; immune tolerance /unresponsiveness; immunopathology; model design /development; molecular biology; nucleotidyltransferase; polymerase chain reaction; receptor binding; receptor expression; skin; surface antigens; thymus; transfection

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.

免疫系统的主要作用是区分自身 和非我。 抗原的特异性识别取决于 淋巴细胞产生多种克隆受体的能力。 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连接和随机的位点 添加连接核苷酸。 后一个过程出现 与末端脱氧核苷酸转移酶 (TdT) 同时发生 活动，尽管 TdT 的贡献尚未正式 已在体内得到证实。 T 细胞受体库的控制至关重要 以预防自身免疫性疾病。 虽然αβT细胞 在胸腺中进行选择； γδT细胞的位点 选择仍然是一个深入调查的主题。 小鼠期间 胎儿生命中，γδT 细胞前体的初始波表达 有限的连接多样性和选定的种系库。 成人 树突状表皮细胞 (DEC) 具有相似的种系 TCR 库 并且也表达很少的连接多样性。 在这项研究中，我们建议 培育出在胎儿期高水平表达 TdT 的转基因小鼠 生活。 通过对 γ δ 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 体内N区多样性产生的活性。 通过 检查成人 DEC 细胞，我们将确定是否 在该 T 细胞亚群中发现的几乎单形 T 细胞受体是 积极选择的结果，或者仅仅是由于它们的衍生 胎儿胸腺细胞同样未能表现出连接多样性。 这些研究不仅应该揭示控制机制 T 细胞抗原受体库的多样化，但在 未来将让我们检验异常多元化的效果 γβT 细胞发育及其他方面的全部 自身免疫性疾病的小鼠模型。