Class II MHC Antigen Processing in Dendritic Cells

描述（由申请人提供）：拟议研究的广泛长期目标是表征树突状细胞（DC）中的抗原加工和呈递途径，以及这些途径如何与其启动和调节免疫应答的功能相关。拟议的研究旨在确定DC内肽和蛋白质衍生抗原加载到II类MHC蛋白上的位置，以及树突状细胞成熟如何调节这一点;确定未成熟DC中存在的空II类MHC蛋白缺乏加载的分子基础;评估空II类MHC分子可能的功能作用;并确定HLA-DR 1的无肽开放构象的结构特征。这些目标将使用细胞和生物化学测定来实现，以跟踪不同发育状态下抗原呈递细胞中II类MHC蛋白的占用率和肽结合活性，并使用细胞和免疫学测定来跟踪抗原呈递的功能结果。一种新的荧光探针肽结合已开发用于此目的。 项目叙述：树突状细胞的抗原呈递在免疫系统识别和应答病原体的过程中起着关键作用。对负责抗原呈递的基本细胞过程的详细理解将是重要的，以指导治疗方法来调节不适当的免疫反应，如在自身免疫和过敏，并努力开发新的疫苗和改善现有的疫苗对感染因子和癌症。

DESCRIPTION (provided by applicant): The broad, long-term objective of the proposed research is to characterize antigen processing and presentation pathways in dendritic cells (DC), and how these relate to their function in initiating and regulating immune responses. The proposed research is intended to determine the location within DC where peptide and protein-derived antigens are loaded onto class II MHC proteins, and how this is regulated by dendritic cell maturation; to determine the molecular basis for the lack of loading of empty class II MHC proteins present in immature DC; to evaluate possible functional roles for empty class II MHC molecules; and to determine structural characteristics of the peptide-free open conformation of HLA-DR1. These goals will be achieved using cellular and biochemical assays to follow the occupancy and peptide binding activity of class II MHC proteins in antigen presenting cells in different developmental states, and using cellular and immunological assays to follow the functional outcomes of antigen presentation. A novel fluorometric probe of peptide binding has been developed for this purpose. PROJECT NARRATIVE: Antigen presentation by dendritic cells plays a key role in the process by which the immune system recognizes and responds to pathogens. A detailed understanding of the basic cellular processes responsible for antigen presentation will be important to guide therapeutic approaches to regulating inappropriate immune responses as in autoimmunity and allergy, and for efforts to develop new vaccines and to improve existing vaccines against infectious agents and cancer.