Analysis of Class II MHC and CD1d antigen presentation pathways in skin-derived d

描述（由申请人提供）：树突状细胞（DC）是外周免疫系统的哨兵，通过液相摄取和内吞作用持续监测其周围的病原体。当检测到病原体衍生的片段时，DC吞噬外来物质并在此过程中被激活。吞噬的蛋白质被加工并作为肽/MHC复合物展示给II类MHC限制性T细胞，而脂质被掺入CD 1/β 2 m/脂质复合物中以呈递给CD 1限制性T细胞。通过对B细胞系以及在更有限的程度上对培养的DC进行生物化学和细胞生物学分析，了解了关于II类MHC分子的内体抗原加工、装载和呈递的许多已知内容。新的方法学现在使得有可能在表达绿色荧光蛋白（GFP）-II类MHC融合蛋白的小鼠表皮中原位观察活的II类MHC阳性DC对红色荧光抗原的摄取。可在活细胞中追踪抗原经历的DC向皮肤引流淋巴结的运输。首先，我们将研究皮肤来源的DC和淋巴结驻留DC中的蛋白质和脂质抗原呈递途径。我们将测试我们的假设，即在炎症期间，皮肤中免疫应答的引发需要表皮驻留DC（朗格汉斯细胞）将蛋白质和脂质抗原两者细胞介导转运至皮肤引流淋巴结。由驻留在淋巴结的T细胞区域中的DC进行的抗原呈递对于T细胞引发是必需的。我们假设抗原从LC转移到非迁移性淋巴结驻留DC是成功的T细胞引发所必需的。因此，LC表达正常抗原内吞作用但内体加工缺陷的突变小鼠应具有有限的表型。相反，表达内体加工缺陷的非迁移性DC的小鼠应表现出降低的T细胞引发能力。我们将研究抗原加工和第二类MHC呈递途径在表皮衍生的朗格汉斯细胞和淋巴结驻留DC亚型。最后，我们成功地建立了一种新的小鼠模型，用于研究体内CD 1介导的抗原呈递。将在CD 1d-黄色荧光蛋白基因敲入小鼠中研究CD 1d对源自皮肤的免疫应答的可能参与。

DESCRIPTION (provided by applicant): Dendritic cells (DCs) are sentinels of the peripheral immune system that continuously survey their surroundings for pathogens, by fluid phase uptake and endocytosis. When pathogen-derived fragments are detected, DCs engulf the foreign material and in the process become activated. Engulfed proteins are processed and displayed as peptide/MHC complexes to Class II MHC-restricted T cells, while lipids are incorporated into CD1/(32m/lipid complexes for presentation to CD1-restricted T cells. Much of what is known about endosomal antigen processing, loading and presentation of Class II MHC molecules was learned through biochemical and cell biological analysis of B cell lines, and to a more limited extent, of cultured DCs. New methodology now makes it possible to visualize the uptake of red fluorescent antigen by live Class II MHC-positive DCs in situ in the epidermis of mice that express green fluorescent protein (GFP)-Class II MHC fusion proteins. Trafficking of antigen-experienced DCs to skin-draining lymph nodes can be tracked in live cells. First, we will study the protein and lipid antigen-presentation pathways in skin-derived DCs and lymph node-resident DCs. We will test our hypothesis that during inflammation, priming of immune responses in the skin requires cell-mediated transport of both protein and lipid antigens by epidermis- resident DCs (Langerhans cells) to skin-draining lymph nodes. Antigen presentation by DCs that reside in the T cell area of lymph nodes is essential for T cell priming. We hypothesize that antigen transfer from LC to a non-migratory lymph node-resident DCs is necessary for successful T cell priming to occur. Accordingly, mutant mice in which LCs express normal antigen endocytosis but defective endosomal processing should have limited phenotype. In contrast, mice expressing non-migratory DCs defective in endosomal processing should exhibit reduced T cell priming capacities. We will study antigen processing and Class II MHC presentation pathways in epidermis-derived Langerhans cells and lymph node-resident DC subtypes. Finally, we have succeeded to generate a new mouse model to study CD1-mediated antigen presentation in vivo. The possible involvement of CD1d to immune responses originating in the skin will be investigated in CD1d- yellow fluorescent protein knock-in mice.