Tlaskalová-Hogenová H, Farré-Castany M A, Stĕpánková R, Kozáková H, Tucková L, Funda D P, Barot R, Cukrowska B, Sinkora J, Mandel L
Department of Immunology and Gnotobiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Folia Microbiol (Praha). 1995;40(4):385-91. doi: 10.1007/BF02814746.
Mucosal surfaces covered by a layer of epithelial cells represent the largest and most critical interface between the organism and its environment. The barrier function of mucosal surfaces is performed by the epithelial layer and immune cells present in the mucosal compartment. As recently found, epithelial cells, apart from their participation in absorptive, digestive and secretory processes perform more than a passive barrier function and are directly involved in immune processes. Besides the well known role of epithelial cells in the transfer of polymeric immunoglobulins produced by lamina propria B lymphocytes to the luminal content of mucosals (secretory Igs), these cells were found to perform various other immunological functions, to interact with other cells of the immune system and to induce an efficient inflammatory response to microbial invasion: enzymic processing of dietary antigens, expression of class I and II MHC antigens, presentation of antigens to lymphocytes, expression of adhesive molecules mediating interaction with intraepithelial lymphocytes and components of extracellular matrix, production of cytokines and probable participation in extrathymic T cell development of intraepithelial lymphocytes. All these functions were suggested to influence substantially the mucosal immune system and its response. Under immunopathological conditions, e.g. during infections and inflammatory bowel and celiac diseases, both epithelial cells and intraepithelial lymphocytes participate substantially in inflammatory reactions. Moreover, enterocytes could become a target of mucosal immune factors. Mucosal immunosurveillance function is of crucial importance in various pathological conditions but especially in the case of the most frequent malignity occurring in the intestinal compartment, i.e. colorectal carcinoma. Proper understanding of the differentiation processes and functions of epithelial cells in interaction with other components of the mucosal immune system is therefore highly desirable.
覆盖着一层上皮细胞的黏膜表面是机体与其环境之间最大且最关键的界面。黏膜表面的屏障功能由上皮层和黏膜区室中存在的免疫细胞执行。最近发现，上皮细胞除了参与吸收、消化和分泌过程外，还具有不止被动的屏障功能，并且直接参与免疫过程。除了上皮细胞在将固有层B淋巴细胞产生的聚合免疫球蛋白转移至黏膜腔内容物（分泌型免疫球蛋白）中所起的众所周知的作用外，还发现这些细胞执行各种其他免疫功能，与免疫系统的其他细胞相互作用，并对微生物入侵引发有效的炎症反应：饮食抗原的酶促加工、I类和II类主要组织相容性复合体（MHC）抗原的表达、向淋巴细胞呈递抗原、表达介导与上皮内淋巴细胞和细胞外基质成分相互作用的黏附分子、产生细胞因子以及可能参与上皮内淋巴细胞的胸腺外T细胞发育。所有这些功能都被认为会对黏膜免疫系统及其反应产生重大影响。在免疫病理条件下，例如在感染、炎症性肠病和乳糜泻期间，上皮细胞和上皮内淋巴细胞都大量参与炎症反应。此外，肠上皮细胞可能成为黏膜免疫因子的靶标。黏膜免疫监视功能在各种病理状况下都至关重要，尤其是在肠道最常见的恶性肿瘤即结直肠癌的情况下。因此，非常有必要正确理解上皮细胞与黏膜免疫系统其他成分相互作用时的分化过程和功能。
