ANTIGEN PRESENTATION IN INSULIN DEPENDENT DIABETES MELLITUS

胰岛素依赖型糖尿病中的抗原呈递

• 批准号: 6268246
• 负责人: EMIL Raphael UNANUE
• 金额: $ 7.97万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-06-01 至 1999-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6268246
• 关键词: B lymphocyte; MHC class II antigen; NOD mouse; SDS polyacrylamide gel electrophoresis; T lymphocyte; antigen presentation; antigen presenting cell; autoimmunity; binding proteins; biochemistry; cell cell interaction; cellular immunity; chemical association; crosslink; diabetes mellitus genetics; genetically modified animals; immune tolerance /unresponsiveness; immunogenetics; insulin dependent diabetes mellitus; leukocyte activation /transformation; pancreatic islets; peptides; protein sequence; synthetic peptide; tissue /cell culture

We propose to examine the peptide-binding properties of the class II MHC molecule (I-Ag7) from NOD mice. Our proposal is based on the following findings; i) Ag7 molecules isolated from a variety of Antigen Presenting Cells are unstable when examined by SDS. PAGE, ii) this unstability does not seem to be caused by a lack of association with Invariant chain or by a lack of processing and assembly of intracellular Ag7, iii) all peptides so far examined bind very weakly to Ag7 either from purified molecules or in APC, iv) the rate of dissociation of all peptides tested is very fast and t his increased off-rate is dramatically evident in T cell assays. Indeed T cells fail to respond if the peptide is not in the culture all of the time, v) preliminary studies indicate that the beta cell diabetogenic antigen behaves the same. These results led us to speculate that the weak binding of peptides by Ag7 is, contrary to expectations, a feature that does not allow for tolerance of autoreactive T cells. The proposal called for, first, an extensive biochemical characterization of Ag7 and its interaction with peptides, including the use of photoaffinity labeled peptides. Second, we will examine how APC bind peptides, their immunogenicity and their time of persistence. For both these issues we select foreign peptides, known autoreactive peptides, and peptides that are isolated from Ag7 molecules. A third goal examines the immune response to peptides bound weakly to Ag7. We propose two experiments, one is an analysis of a peptide processed by APC from Ealpha chain and which interacts in dramatically different ways when binding to Ag7 or Ab. We will test the immune response in (NOD X B6) F1 mice expressing the E chain (and, in principle, tolerant to it). Another experiment attempts to engineer the Aalpha chain of NOD so as to produce a stable, high affinity binding Ag7. If successful we will compare the reaction of T cells to it, both in culture and in in vivo experiment. Finally, we plan to examine these phenomena on human IDDM susceptible class II molecules DQ2 and DQ8.

我们建议检查II类MHC的肽结合特性 来自点小鼠的分子（I-AG7）。 我们的建议基于以下 发现; i）从各种抗原呈现的Ag7分子 通过SDS检查细胞不稳定。 页，ii）这种不稳定确实如此 似乎不是由于与不变链缺乏关联或 缺乏细胞内AG7的加工和组装，ii）所有肽 到目前为止，检查的与Ag7结合了纯化的分子或 在APC中，iv）所有测试肽的解离速率非常快 在T细胞测定中，他的非率提高显而易见。 实际上，如果肽不在培养中，则T细胞无法做出反应 时间，v）初步研究表明β细胞糖尿病性 抗原的行为相同。 这些结果使我们推测弱 与期望相反，AG7对肽的结合是一种特征 不允许耐受自动反应性T细胞。 该提议首先要求广泛的生化特征 AG7及其与肽的相互作用，包括使用 光性标记为肽。 其次，我们将研究APC如何绑定 肽，免疫原性和持久时间。 两者 这些问题我们选择了外国肽，已知的自动反应性肽以及 从Ag7分子分离的肽。 第三个进球检查 对肽的免疫反应弱结合到Ag7。 我们提出了两个 实验，一个是对APC从EALPHA处理的肽的分析 链条和以不同的方式相互作用时 AG7或AB。 我们将测试（nod x B6）F1小鼠中的免疫反应 表达E链（原则上，对其宽容）。 其他 实验试图设计点头的Aalpha链，以产生 稳定，高亲和力结合AG7。 如果成功的话，我们将比较 T细胞在培养和体内实验中的反应。 最后，我们计划检查有关人IDDM易感阶级的这些现象 II分子DQ2和DQ8。