ASSEMBLY AND FUNCTION OF THE T CELL RECEPTOR/CD3 COMPLEX

胸腺衍生的淋巴细胞（T细胞）是免疫球蛋白的主要成分。 肠相关淋巴组织（GALT），并可能发挥重要作用 在许多肠道疾病的发病机制中。 这些 包括诸如炎症性肠病、传染性 在移植物抗宿主病中， T淋巴细胞增加，存在的T淋巴细胞被激活。 在 为了深入了解这些疾病， 了解T细胞功能的基本机制。 T细胞 识别处理过的标称抗原， 主要组织相容性复合体（MHC）的组成部分， 通过T细胞受体（TCR）与靶细胞表面结合。 TCR， 其支持抗原和MHC识别，由 两种免疫球蛋白样蛋白，α和β或ω， δ的 与TCR非共价结合的是非变异的 CD 3复合物的链; CD 3 ω，δ，β和， 在TCR结合后的跨膜信号传导中可能是重要的 抗原/MHC。 为了使T细胞对抗原/MHC产生应答， 必须正确组装TCR/CD 3的多肽链 并将其运输到细胞表面。 组装 TCR/CD 3复合物蛋白与T细胞功能活性 是紧密相连的。 本研究的具体目的 是（1）通过使用特定的转染研究， T细胞突变体和非T细胞中的cDNA描述了 TCR/CD 3组装和表面表达所需的链 复杂;（2）定义组装中重要的结构域， 体外定点突变cDNA表面表达 和饱和诱变，并将改变的cDNA导入 T细胞;（3）定义信号传导中重要的结构域 通过在体外用定点突变cDNA进行转导， 饱和诱变以及特异性限制 将改变的cDNA转染入T细胞， (4)表征T细胞活化突变体中的功能缺陷 通过将正常cDNA转染到T细胞突变体中， 克隆并测序异常cDNA。 指导下 考克斯特霍斯特博士的研究，这些研究将为研究者提供 在分子免疫学方面有丰富的经验 这 知识在未来可以直接作为独立的 研究T细胞分化的学术研究者， 在GALT中激活。

Thymus derived lymphocytes (T cells) ar a major component of the gut associated lymphoid tissue (GALT) and may play a prominent role in the pathogenesis of a number of intestinal disorders. These include such diseases as inflammatory bowel disease, infectious enteritides and graft-versus-host disease in which the number of T lymphocytes are increased and those present are activated. In order to gain an insight into these disorders, it is important to understand the fundamental mechanisms of T cell function. A T cell recognizes processed nominal antigens in association with the components of the major histocompatibility complex (MHC) on the surface of a target cell via the T cell receptor (TCR). The TCR, which subserves both antigen and MHC recognition, is composed of two immunoglobulin like proteins, alpha and beta or omega and delta. Noncovalently associated with the TCR are the nonvariant chains of the CD3 complex; CD3 omega, delta, epsilon, and , which may be important in transmembrane signaling after the TCR binds antigen/MHC. In order for a T cell to respond to antigen/MHC it must correctly assemble the polypeptide chains of the TCR/CD3 complex and transport them to the cell surface. Assembly of the protein of TCR/CD3 complex and functional competence of the T cell are, therefore, closely coupled. The specific aims of this study are to (1) through the use of transfection studies with specific cDNA's in T cell mutants and non-T cells, delineate the protein chains required for assembly and surface expression of the TCR/CD3 complex; (2) to define structural domains important in assembly and surface expression by mutating cDNA's in vitro with site directed and saturation mutagenesis and transfecting the altered cDNA's into T cells; (3) to define structural domains important in signal transduction by mutating cDNA's in vitro with site directed and saturation mutagenesis as well as with specific restriction endonucleases and transfecting the altered cDNA's into T cells and (4) characterize the functional defect in T cell activation mutants by transfection of normal cDNA's into the T cell mutants and cloning and sequencing the abnormal cDNA's. Under the direction of Dr. Cox Terhorst, these studies will provide the investigator with an extensive experience in molecular immunology. This knowledge can, in the future, be directly applied as an independent academic investigator to studies of T cell differentiation and activation in the GALT.