9.黏膜免疫 研究生.ppt

肠系膜淋巴结（肿大） 肠系膜淋巴结 * 第二十八页，编辑于星期三：四点 四十五分。 黏膜免疫系统含有大量效应淋巴细胞 黏膜免疫系统中独特的树突状细胞 黏膜固有层中T细胞的致敏和归巢 参与适应性黏膜免疫应答的免疫细胞 第二十九页，编辑于星期三：四点 四十五分。 肠道中T细胞依赖的IgA 抗体类别转换机制 派氏集合淋巴结圆丘状隆起部位的DC 获取由M 细胞提交的肠腔抗原并迁移至滤泡区近旁后，将抗原提呈给初始 CD4 T 细胞并使之激活和分化成Th。Th与借助其BCR识别了抗原的B细胞发生相互作用，通过T-B间CD40L-CD40 的结合，B细胞分化成产生IgA的浆细胞。该过程受DC产生的一氧化氮及TGF-?的促进。由此产生的浆细胞经由血 循环再归槽至固有层，所分泌的高亲和力IgA抗体，经过上皮细胞胞吞转换进入肠腔，与当初致敏的肠腔抗原结合。 CD40L CD40 DC 初始T 激活的Th NO B 浆母细胞 TGF-? 经过血流 派氏集合淋巴结 淋巴滤泡 固有层 肠腔 基底膜 上皮 细胞 肠腔抗原 IgA IgA 分泌IgA 浆细胞 DC B7 CD28 M 细胞 第三十页，编辑于星期三：四点 四十五分。 Capture of antigens from the intestinal lumen by mononuclear cells in the lamina propria. First panel: soluble antigens such as food proteins might be transported directly across or between enterocytes, or there might be M cells in the surface epithelium outside Peyers patches. Second panel: enterocytes can capture and internalize antigen:antibody complexes by means of the FeRn on their surface and transport them across the epithelium by transcytosis. At the basal face of the epithelium, lamina propria dendritic cells expressing FeRn and other Fe receptors pick up and internalize the complexes. Third panel: an enterocyte infected with an intracellular pathogen undergoes apoptosis and its remains are phagocytosed by the dendritic cell. Fourth panel: mononuclear cells have been seen extending processes between the cells of the epithelium without disturbing its integrity. The cell process could pick up and internalize antigen from the gut lumen and then retract. The micrograph shows mononuclear cells, which may be dendritic cells or macrophages, (stained green with a fluorescent tag on the CD11 c molecule) in the lamina propria of a villus of mouse small intestine. The epithelium is not stained and appears black, but its luminal (outer) surface is shown by the white line. A cell process has squeezed between two epithelial cells and its tip is present in the lumen of the intestine. Magnification x200. Micrograph from Niess, J.H., eta/.: Science 2005, 307:254-25