Cytotoxic T Lymphocyte Activation In Vitro and In Vivo

描述（由申请人提供）：需要两种信号（Ag和共刺激）来激活初始CD 8 T细胞，但它们是不够的。在前一个授予期间所做的工作提供了强有力的证据，证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响应性记忆群体。信号三可以由IL-12或I型IFN提供，如通过体外活化所证明的，并且在体内通过它们在刺激对肽Ag的应答中替代对佐剂的需要的能力所证明的。因此，第三信号将对Ag的耐受性暴露转化为有效引发。要实现的目标包括：确定IL-12和IFN-α是否为树突状细胞和Ag体内激发的初始CD 8 T细胞活化提供第三信号。将进行实验以确定活化DC的刺激是否需要IL-12和/或IFN-α，以及来自CD 4细胞的CD 40依赖性帮助是否涉及刺激DC以产生信号3细胞因子。体内实验将使用细胞因子和受体缺陷小鼠来确定CTL应答依赖于IL-12和/或I型IFN的程度。目标2.确定信号3细胞因子对初始CD 8 T细胞活化的影响：基因调节、存活和效应子功能。功能研究和基因阵列分析提出了一些关于信号三有助于激活的机制的假设，这些假设将被测试。目标3：确定幼稚细胞中受信号3细胞因子调节的基因在记忆细胞中的表达。存储器单元不需要第三信号被激活，并且将确定用于此的基础。预计这些研究的结果将有助于对产生CD 8 T细胞应答的要求的新见解。此外，这些结果将具有重要的意义，操纵这些反应的保护性和治疗性免疫，并可能诱导耐受性，这是可取的，反应被阻止。

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.