Cytotoxic T Lymphocyte Activation In Vitro and In Vivo

描述(申请人提供)：激活初始CD8T细胞需要两种信号(抗原和共刺激)，但这两种信号是不够的。在之前的授予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张，并发展效应器功能和反应记忆群体。信号三可以由IL-12或I型IFN提供，如体外激活所证明的，以及在体内通过它们在刺激多肽Ag的反应中取代佐剂的能力所证明的。因此，第三个信号将对银的耐受暴露转化为有效的启动。本研究的目的包括：1.确定IL-12和干扰素-α是否为树突状细胞激活初始CD8 T细胞和体内抗原攻击提供第三信号。将进行实验以确定激活的DC刺激是否需要IL-12和/或干扰素-α，以及CD40依赖的CD4细胞的帮助是否涉及刺激DC产生信号3细胞因子。体内实验将使用细胞因子和受体缺陷的小鼠来确定CTL反应对IL-12和/或I型IFN的依赖程度。目的2.探讨信号3细胞因子对初始CD8T细胞活化的影响：基因调控、存活和效应功能。功能研究和基因阵列分析已经就信号3参与激活的机制提出了一些假说，这些假说将得到验证。目的3.检测幼稚细胞中受信号3细胞因子调控的基因在记忆细胞中的表达。存储单元不需要第三信号被激活，这一点的基础将被确定。预计这些研究的结果将有助于对产生CD8 T细胞反应的需求提供新的见解。此外，这一结果将对控制这些反应用于保护性和治疗性免疫具有重要意义，并可能对诱导免疫耐受具有重要意义，因为需要预防这些反应。

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.