Differentiation and Regulation of CTL

描述（由申请人提供）：T细胞介导的免疫应答需要T细胞和抗原（Ag）呈递细胞（APC）之间的接触依赖性信息交换。幼稚T细胞由次级淋巴器官如外周淋巴结（PLN）中的成熟树突状细胞（DC）引发。经过几天的活化，增殖的T细胞分化成细胞毒性效应细胞（CTL）。它可以杀死APC。CTL活性被认为是由几种机制控制的，包括调节性T细胞（Treg）的作用和CTL在生存信号撤回时经历凋亡的倾向。因此，在CTL应答达到高峰后，Ag特异性T细胞池收缩，留下一小群长寿的记忆细胞，当Ag返回时，这些记忆细胞比初始T细胞反应更强烈。人们普遍认为，T细胞所采取的职业决定是由表面相互作用的通信分子的时空排列来调节的 T细胞和APC。然而，PLN中T细胞-APC相互作用的物理性质和动力学仍然在很大程度上未被探索。在该项目的前期工作中，我们开发了一种新的多光子活体显微镜（MP-IVM）模型来研究麻醉小鼠完整腘LN中的APC和TCR转基因CDS T细胞。这种成像方法以亚细胞分辨率产生相互作用细胞的3D延时电影，并将用于解决以下两个具体目标：1.分析PLN和2.）探讨Ag特异性Treg对CTL分化和功能的影响。所提出的实验将产生一个全面的，面向机制的CTL分化，功能和调节分析。这些信息可能导致临床免疫调节的改进策略，例如用于疫苗接种、肿瘤治疗和感染性、炎症性和自身免疫性疾病的治疗。

DESCRIPTION (provided by applicant): T cell-mediated immune responses require contact-dependent information exchange between T cells and antigen (Ag)-presenting cells (APC). Naive T cells are primed by mature dendritic cells (DC) in secondary lymphoid organs, such as peripheral lymph nodes (PLN). After a few days of activation, the proliferating T cells differentiate into cytotoxic effector cells (CTL). which can kill APC. CTL activity is thought to be controlled by several mechanisms, including the action of regulatory T cells (Treg) and the propensity of CTL to undergo apoptosis upon withdrawal of survival signals. Thus, after the height of a CTL response, the pool of Ag-specific T cells contracts, leaving behind a small population of long-lived memory cells, which respond more vigorously than naive T cells when the Ag returns. It is widely held that the career decisions taken by T cells are regulated by the spatio-temporal arrangement of interacting communication molecules on the surface of T cells and APC. However, the physical nature and the kinetics of T cell-APC interactions in PLN are still largely unexplored. In preliminary work for this project, we have developed a new multiphoton intravital microscopy (MP-IVM) model to study APC and TCR transgenic CDS T cells in intact popliteal LN of anesthetized mice. This imaging approach produces 3D time-lapse movies of interacting cells at subcellular resolution and will be used to address the following two specific aims: 1.) To analyze the spatial, temporal and behavioral relationship between CTL and APC in PLN and 2.) To explore the effect of Ag-specific Treg on CTL differentiation and function. The proposed experiments will generate a comprehensive, mechanism oriented analysis of CTL differentiation, function and regulation. This information may lead to improved strategies for clinical immunomodulation, e.g. for vaccinations, tumor therapy and treatment of infectious, inflammatory and autoimmune diseases.