CD8+ CTL RECOGNITION OF MHC CLASS I

描述(摘自申请者的摘要)：T细胞受体 细胞毒性T淋巴细胞(CTL)利用TCR及其辅受体CD8。 识别病毒感染或恶性的靶细胞。这样的目标单元 表达具有以下结合的多肽配体的I类MHC分子 由TCR/CD8复合体特异性识别。在这里提出的工作 我将研究TCR/CD8分子相互作用的几个方面 具有I类/多肽。最近确定了一项单一的 多肽在LD同种异体识别中具有免疫优势。这一观察结果将 以确定这种免疫优势是否反映在 该多肽的定量表达，该多肽与 LD，即TCR对LD/肽复合体的亲和力。作为一种 作为早期研究的延伸，这个实验室开发了一种方法来 产生针对H-2LD的多肽特异性同种异体反应CTL。使用这个 方法学，将产生多肽特异性同种异体反应CTL 已知的内源性LD配体以确定它们是否在 同种异体反应及其表达是否普遍存在于 不同的细胞类型。我们还将测试同种异体CTL，特异性 对于内源性LD配体，比起 病毒多肽配体的同源CTL。为了更好地理解 特定的TCR结构基序如何与第I类或其界限相互作用 Ligand，一个广泛的I类定点突变小组将是 进行了结构功能分析。这些研究还将 包括受同一类I限制但特定的几个CTL克隆 对于不同的多肽以及受相似类别限制的CTL克隆 I分子和特异性为同一多肽。作为对 早期的研究定位CD8识别位点，I类阿尔法-3 未被CD8识别的突变体将在体内和体外进行表征 为了更好地确定CD8在诱导CTL反应中的作用 在CTL认可的I级。总而言之，拟议的实验 将利用独特的资源和方法来定义各种 控制TCR/CD8分子功能相互作用的参数 靶细胞上含有I类/多肽分子的CTL。

DESCRIPTION (Adapted from the Applicant's abstract): The T-cell receptor (TCR) and its coreceptor CD8 are used by cytotoxic T lymphocytes (CTL) to identify virus-infected or malignant target cells. Such target cells express class I MHC molecules with bound peptide ligands that are specifically recognized by the TCR/CD8 complex. The work proposed here will investigate several aspects of the molecular interaction of TCR/CD8 with class I/peptide. It has been recently determined that a single peptide is immunodominant in Ld- allorecognition. This observation will be extended to determine if this immunodominance is reflected in the quantitative expression of this peptide, the affinity of the peptide for Ld, or the affinity of the TCR for the Ld/peptide complex. As an extension of earlier studies, this laboratory has developed a method to generate peptide-specific alloreactive CTL to H-2Ld. Using this methodology, peptide-specific alloreactive CTL will be generated to known endogenous Ld ligands to determine whether they function in allogeneic responses and whether their expression is ubiquitous on different cell types. We will also test whether allogeneic CTL, specific for endogenous Ld ligands, are more peptide cross-reactive than syngeneic CTL specific for viral peptide ligands. To better understand how specific TCR structural motifs interact with class I or its bound ligand, an extensive panel of site-specific mutants of class I will be subjected to structure-function analyses. These studies will also include several CTL clones restricted by the same class I but specific for different peptides as well as CTL clones restricted by similar class I molecules and specific for the same peptide. As an extension of earlier studies mapping the CD8 recognition site, a class I alpha-3 mutant not recognized by CD8, will be characterized in vivo and in vitro to better define the role of CD8 in the induction of CTL responses and in class I recognition by CTL. In summary, the proposed experiments will exploit unique resources and approaches to define various parameters governing functional interactions of the TCR/CD8 molecules on CTL with class I/peptide molecules on target cells.