Imaging and Function of the Immunological Synapse

描述（由申请方提供）：T淋巴细胞仅将抗原视为与抗原呈递细胞（APC）表面上的MHC分子结合的小肽。除了T细胞抗原受体（TCR）和负载肽的MHC之外，数十种其他细胞表面分子在决定T细胞/APC相互作用的结果中发挥必要或调节作用。抗原识别伴随着这些分子的大规模的细胞因子依赖性重排，以在T细胞和APC之间形成被称为“免疫突触”的有组织的接触界面。“该应用基于突触形成作为完全T细胞活化的检查点起作用的假设，整合关于TCR配体的数量和质量以及APC的性质和活化状态的信息（货车der Merwe等，2000 Semin. Immunol.12：5）。 为了验证这一假设，将使用最先进的视频显微镜来跟踪钙信号和鼠TCR转基因T细胞与携带荧光MHC分子的成纤维细胞之间的突触形成，所述荧光MHC分子装载有共价连接的抗原肽，以确定MHC分子在突触中的积累是否是肽特异性的，并且如果是，则确定在突触形成期间何时发生分选。同样的技术将被用来确定是否MHC分子负载拮抗肽也积累在突触中，以及它们如何影响突触的形成或功能。将制备负载有共价连接的抗原肽的荧光MHC分子转基因小鼠，并用于研究T细胞和生理性抗原递呈细胞（树突状细胞和B细胞）在不同激活和成熟状态下的突触形成、功能和辅助分子需求。 拟议的实验将有助于对T细胞/APC相互作用的基本理解，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中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.