TCR/PEPTIDE/MHC INTERACTION DURING POSITIVE SELECTION

正选择过程中 TCR/肽/MHC 相互作用

• 批准号: 2649925
• 负责人: JANKO Z. NIKOLICH
• 金额: $ 16.17万
• 依托单位: SLOAN-KETTERING INST CAN RESEARCH
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-30 至 1998-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2649925
• 关键词: MHC class I antigen; T cell receptor; autoimmunity; cytotoxic T lymphocyte; gene mutation; genetically modified animals; laboratory mouse; laboratory rat; peptides; site directed mutagenesis; thymus; tissue /cell culture; tissue mosaicism

T cell antigen recognition involves a contact between the T cell receptor (TcR) and the foreign antigenic peptide bound to the restricting major histocompatibility complex (MHC) molecule. MHC restriction is learned in the thymus. The T cell receptor (TCR) on a developing thymocyte must bind self MHC molecules on thymic cortical epithelium, in order for the thymocyte to be positively selected and allowed to complete maturation. Positive selection in the thymus occurs in the absence of foreign peptides. Self peptides, bound to self MHC molecules, play an important role in this process. However, the relative importance of TCR:self peptide versus the TCR:MHC contact during positive selection remains controversial. Elucidation of the molecular details of this process is of central importance for our understanding of fundamental principles of TCR recognition, selection of a diverse TCR repertoire, tolerance and autoimmunity. To investigate the TCR:peptide:MHC contact during positive selection, two unique systems will be used. A new MHC class I molecule was engineered to evaluate whether, under physiological conditions, all TCRs require a contact with peptides during positive selection, or whether some may rely on the MHC contact alone. In the second system, functional differences in positive selection by two class 1 MHC variants correlate to a TCR utilization pattern. We shall analyze functional reactivities and TCR sequences of these cells, to position the TCR over the selecting MHC molecule, with the help of molecular modeling and crystal structures of both MHC variants. Site-directed mutagenesis and single-chain TCR transgenic animals will then be used to determine which contacts result in restricted selection patterns. Above studies will be significantly enhanced by testing of the fine TCR repertoire using a recently developed method of peptide priming of class 1 restricted T cells.

T 细胞抗原识别涉及 T 细胞受体之间的接触 (TcR) 和与限制性主要结合的外来抗原肽 组织相容性复合体 (MHC) 分子。 MHC 限制是在 胸腺。 发育中的胸腺细胞上的 T 细胞受体 (TCR) 必须 将自身 MHC 分子结合在胸腺皮质上皮上，以便 胸腺细胞被积极选择并使其完全成熟。 胸腺中的正选择发生在没有外源的情况下 肽。 与自身 MHC 分子结合的自身肽发挥着重要作用 在此过程中的作用。 然而，TCR:self 的相对重要性 正选择过程中肽与 TCR:MHC 接触的关系仍然存在 有争议的。 阐明该过程的分子细节是 对于我们理解基本原则至关重要 TCR 识别、多样化 TCR 库的选择、耐受性和 自身免疫。 为了研究正选择期间 TCR: 肽: MHC 接触，两个 将使用独特的系统。 一种新的 MHC I 类分子是 旨在评估在生理条件下所有 TCR 是否 需要在正选过程中与肽接触，或者是否 有些可能仅依赖于 MHC 接触。 在第二个系统中， 两个 1 类 MHC 变体在正选择中的功能差异 与 TCR 利用模式相关。 我们将分析功能 这些细胞的反应性和 TCR 序列，以将 TCR 定位在 在分子建模的帮助下选择 MHC 分子 两种 MHC 变体的晶体结构。 定点诱变和 单链 TCR 转基因动物将用于确定 哪些接触会导致选择模式受到限制。 以上研究 通过测试精细的 TCR 指令将显着增强 使用最近开发的 1 类肽引发方法 限制性T细胞。