Cytotoxic T Lymphocyte Activation In Vitro and In Vivo

描述（由申请人提供）：激活初始CD8 T细胞需要两种信号（Ag和共刺激），但它们是不够的。在之前的授权期间所做的工作提供了强有力的证据，表明细胞需要第三个信号才能进行克隆扩增并发展效应功能和反应性记忆群体。信号3可以由IL-12或I型ifn提供，如在体外激活所证明的那样，并且在体内它们能够替代佐剂来刺激对肽Ag的反应。因此，第三个信号将耐受暴露于Ag转化为有效的启动。要实现的目标包括：目标1。为了确定IL-12和ifn - α是否为树突状细胞激活CD8 T细胞和体内Ag攻击提供了第三个信号。实验将确定激活DC的刺激是否需要IL-12和/或ifn - α，以及CD4细胞的cd40依赖性帮助是否涉及DC的刺激以产生信号3细胞因子。体内实验将采用细胞因子和受体缺乏的小鼠来确定CTL反应依赖于IL-12和/或I型ifn的程度。目标2。探讨信号3细胞因子对初始CD8 T细胞活化的影响：基因调控、存活和效应因子功能。功能研究和基因阵列分析已经提出了一些关于信号3促进激活机制的假设，这些假设将被测试。目标3。目的：探讨信号3细胞因子在幼稚细胞中调控基因在记忆细胞中的表达。记忆细胞不需要第三个信号来激活，其基础将被确定。预计这些研究的结果将为产生cd8 T细胞反应的需求提供新的见解。此外，该结果将对控制这些反应以进行保护性和治疗性免疫，以及在希望防止反应的情况下诱导耐受性具有重要意义。

DESCRIPTION (provided by applicant): Two signals (Ag and costimulation) are required to activate naive CD8 T cells, but they are not sufficient. Work done during the previous granting period has provided strong evidence that the cells need a third signal in order to undergo clonal expansion and develop effector function and a responsive memory population. Signal three can be provided by IL-12 or Type I IFNs, as demonstrated by in vitro activation, and in vivo by their ability to replace the need for adjuvant in stimulating a response to peptide Ag. Thus, the third signal converts a tolerizing exposure to Ag to effective priming. The aims to be pursued include: Aim 1. To determine if IL-12 and IFN-alpha provide the third signal for naive CD8 T cell activation by dendritic cells and by in vivo challenge with Ag. Experiments will be done to determine if stimulation by activated DC requires IL-12 and/or IFN-alpha, and whether CD40-dependent help from CD4 cells involves stimulation of DC to produce signal 3 cytokines. In vivo experiments will employ cytokine- and receptor-deficient mice to determine the extent to which CTL responses depend upon IL-12 and/or Type I IFNs. Aim 2. To determine the effects of signal 3 cytokines on activation of naive CD8 T cells: gene regulation, survival and effector function. Functional studies and gene array analyses have suggested a number of hypotheses regarding mechanisms by which signal three contributes to activation, and these will be tested. Aim 3. To determine expression in memory cells of genes regulated in naive cells by signal 3 cytokines. Memory cells do not require a third signal to be activated, and the basis for this will be determined. It is anticipated that the results of these studies will contribute novel insights into the requirements for generatingCD8 T cell responses. In addition, the results will have important implications for manipulating these responses for protective and therapeutic immunizations, and potentially for induction of tolerance where it is desirable that responses be prevented.