MOLECULAR EVENTS IN ANTIGEN RECOGNITION

辅助性诱导亚群的T细胞识别抗原和 辅助细胞上表达的II类MHC分子。对于球状 蛋白质抗原，抗原必须由附件处理 T细胞识别之前的细胞。小肽可以替代 经过处理的抗原，因为当它们被T细胞识别时 使用带有前缀的辅助单元或Ia支承平面膜 来呈现抗原。我们最近已经能够证明 免疫原肽与Ia-分子特异结合。 用12个这样的多肽组成的小组，我们发现了一个相关性 Ia分子与特定分子结合的能力 多肽和Ia作为限制因素的能力 同一种多肽的元素。此外，我们还提供了 Ia与多肽形成的络合物的证据是 在免疫学上有相关性，正是这种部分 由T细胞受体识别。我们计划延长我们的 抗原-Ia相互作用在辅助性T细胞中作用的研究 单元格响应如下： 1)研究多肽的结构特征 使他们能够与Ia互动。 2)识别自然产生的多肽区域 与Ia结合并与这种结合相关的蛋白质抗原 对这些相同多肽的免疫原性的活性。 3)鉴定和表征Ia分子中的区域(S) 形成Ia的抗原结合部位(S)。 4)三分子络合物的论证和表征 Ia、抗原和T细胞受体之间的关系。 5)研究Ia-多肽相互作用的化学计量学。 试图理解为什么一小部分亲和力被提纯 IA似乎具有结合多肽的能力。

T cells of the helper-inducer subset recognize antigen and the class II MHC molecules expressed on accessory cells. For globular protein antigens, the antigen must be processed by the accessory cells prior to T cell recognition. Small peptides can substitute for processed antigen since they can be recognized by T cells when prefixed accessory cells or Ia bearing planar membranes are used to present antigen. We have recently been able to demonstrate that immunogenic peptides bind specifically to Ia-molecules. With a panel of 12 such peptides we have found a correlation between the capacity of an Ia molecule to bind a particular peptide and the capacity of that Ia to serve as a restriction element of the same peptide. Furthermore, we have provided evidence that the complex formed between Ia and peptide is immunologically relevant and that it is this moiety that is recognized by the T cell receptor. We plan to extend our investigations of the role of antigen-Ia interactions in T helper cell responses as follows: 1) To investigate the structural characteristics of peptides that enable them to interact with Ia. 2) To identify the peptide regions within a naturally occurring protein antigen that bind to Ia and to correlate this binding activity to the immunogenicity of these same peptides. 3) To identify and characterize the region(s) within Ia molecules that form the antigen binding site(s) of Ia. 4) To demonstrate and characterize the tri-molecular complex between Ia, antigen, and T cell receptor. 5) To investigate the stoichiometry of Ia-peptide interaction in an attempt to understand why a small fraction of affinity purified Ia appears capable of binding peptide.