ANERGY AND SIGNALING IN MURINE T CELL SUBSETS

T淋巴细胞的完全激活除了需要 通过TCR/CD3复合体刺激，一个或多个人参与 共刺激分子。对于Th1细胞，TCR复合体的连接 没有共刺激会导致无能，这种状态的特征是 IL-2的产生和增殖能力不足。一个共刺激器 产生IL-2的T细胞的分子是CD28，它与 抗原提呈细胞和其他细胞上表达的配体B7-1和B7-2 单元类型。CTLA4是一种表达在活化T细胞上的同源分子 也与B7-1和B7-2结合但可能具有阴性反应的细胞 具有激活T细胞的功能。与Th1细胞相比，人们所知的更少 关于产生IL-4的Th2细胞的共刺激需求。 本项目的主要目标是描述信令的特征 与无能状态相关的无能Th1克隆的缺陷 确定观察到的变化是否与无能有关 产生IL-2，鉴定正常的信号通路(S) 调节CD28的功能，进行生化分析 结扎CTLA4对Th1和Th2功能的影响 细胞，并鉴定和鉴定共刺激分子(S)为 Th2细胞。这些研究将利用一组油井- 定义了我们实验室生成的Th1和Th2克隆，以及 一系列转基因和基因敲除小鼠。重点将放在积极方面 对信号研究的负面调节将得到一项 表达I-Ad排列的肿瘤细胞转染组， B7-1、B7-2和ICAM-1。由于细胞因子的产生和 已建立的Th2克隆的增殖不受CD28/B7的影响 阻断，调节细胞生长的额外顺式刺激分子 Th2细胞将被鉴定和鉴定。一旦确定， 由这些配体触发的信号通路将与 CD28和IL-1诱导。总的来说，这些研究应该 对顺式刺激因子的功能有更深入的了解 T细胞调控中的受体及其生化信号 激活与失活，以及对不同T细胞的调节 子集。这类信息应该具有广泛的影响 移植、自身免疫和抗病毒免疫反应 癌症。

complete activation of T lymphocytes requires, in addition to stimulation via the TCR/CD3 complex, participation of one or more costimulator molecules. For Th1 cells, ligation of the TCR complex in the absence of costimulation results in anergy, a state characterized by deficient IL-2 production and proliferation. One costimulator molecule for IL-2-producing T cells is CD28, which interacts with the ligands B7-1 and B7-2 expressed on antigen-presenting cells and other cell type. CTLA4 is a homologous molecule expressed on activated T cells that also binds to B7-1 and B7-2 but which may have a negative function for T cell activation. In contrast to Th1 cells, less is known about the costimulatory requirements of IL-4 producing Th2 cells. The principal goals of this Project are to characterize the signaling defects in anergic Th1 clones that correlate with the anergic state, to determine if the observed changes are causally related to an inability to produce IL-2, to identify the normal signaling pathway(s) that mediate the functions of CD28, to analyze the biochemical consequences of CTLA4 ligation on the functions of Th1 and Th2 cells, and to identify and characterize the costimulator molecule(s) for Th2 cells . These studies will take advantage of a panel of well- defined Th1 and Th2 clones generated in our laboratory, as well as a series of transgenic and knockout mice. The focus will be on positive and negative regulation of the signaling studies will be aided by a panel of tumor cell transfectants that express permutations of I-Ad, B7-1, B7-2, and ICAM-1. Inasmuch as cytokine production and proliferation by established Th2 clones are unaffected by CD28/B7 blockage, additional cistimulator molecules that regulate the growth of Th2 cells will be identified and characterized. Once identified, the signaling pathways triggered by these ligands will be contrasted with those induced by CD28 and IL-1. Collectively, these studies should provide a more thorough understanding of the function of cistimulator receptors and their biochemical signals in the control of T cell activation versus inactivation, and in the regulation of distinct T cell subsets. Such information should have broad implications for transplantation, autoimmunity, and the immune response against cancers.