Imaging and Function of the Immunological Synapse

描述(由申请人提供)：T淋巴细胞仅将抗原视为与抗原提呈细胞(APC)表面的MHC分子结合的小肽。除了T细胞抗原受体(TCR)和载肽的MHC外，许多其他细胞表面分子在决定T细胞IL/APC相互作用的结果中起着必要的或调节的作用。抗原识别伴随着这些分子的大规模、依赖于细胞骨架的重排，从而在T细胞和APC之间形成一个有组织的接触界面，称为“免疫突触”。这一应用是基于这样的假设，即突触的形成作为完全T细胞激活的检查点，整合了有关TCR配体的数量和质量以及APC的性质和激活状态的信息(van der Merwe等人)。2000年，塞明。免疫系统。12：5)。 为了验证这一假说，将使用最先进的视频显微镜跟踪TCR转基因小鼠T细胞和携带荧光MHC分子的成纤维细胞之间的钙信号和突触形成，以确定MHC分子在突触中的积累是否具有肽特异性，如果是，则确定在突触形成过程中何时发生分选。同样的技术将被用来确定装载有拮抗肽的MHC分子是否也在突触中积累，以及它们可能如何影响突触的形成或功能。转基因MHC分子共价结合抗原肽的小鼠将被用来研究不同激活和成熟状态的T细胞和生理抗原提呈细胞(树突状细胞和B细胞)之间的突触形成、功能和辅助分子要求。 拟议的实验将有助于对T细胞/APC相互作用的基本了解，这反过来将在移植、自身免疫、过敏、癌症免疫治疗和传染病控制方面具有与健康相关的应用。

DESCRIPTION (provided by the applicant): T lymphocytes see antigen only as small peptides bound to MHC molecules on the surface of antigen presenting cells (APC). In addition to the T cell antigen receptor (TCR) and peptide-loaded MHC, dozens of other cell surface molecules play necessary or modulating roles in determining the outcome of the T ceIl/APC interaction. Antigen recognition is accompanied by large-scale, cytoskeleton-dependent rearrangements of these molecules to form an organized contact interface between the T cell and the APC termed the "immunological synapse." This application is based on the hypothesis that synapse formation functions as a checkpoint for full T cell activation, integrating information on the number and quality of TCR ligands as well as the nature and activation state of the APC (van der Merwe et al. 2000 Semin. Immunol. 12:5). To test this hypothesis, state-of-the-art video microscopy will be used to follow calcium signals and synapse formation between murine TCR transgenic T cells and fibroblasts bearing fluorescent MHC molecules loaded with covalently attached antigenic peptides to determine whether accumulation of MHC molecules in the synapse is peptide-specific, and if so, to determine when sorting occurs during synapse formation. The same techniques will be used to determine whether MHC molecules loaded with antagonist peptides also accumulate in the synapse and how they may affect synapse formation or function. Mice transgenic for fluorescent MHC molecules loaded with covalently attached antigenic peptide will be made and used to study synapse formation, function, and accessory molecule requirements between T cells and physiological antigen presenting cells (dendritic cells and B cells) in different states of activation and maturation. The proposed experiments will contribute to a basic understanding of T cell/APC interactions, which in turn will have health-related applications in transplantation, autoimmunity, allergy, cancer immunotherapy, and control of infectious diseases.