Department of Child Life and Health, University of Edinburgh, Edinburgh, UK.
Inflamm Bowel Dis. 2011 Jan;17(1):382-95. doi: 10.1002/ibd.21379.
The intestinal epithelium not only acts as a physical barrier to commensal bacteria and foreign antigens but is also actively involved in antigen processing and immune cell regulation. The inflammatory bowel diseases (IBDs) are characterized by inflammation at this mucosal surface with well-recognized defects in barrier and secretory function. In addition to this, defects in intraepithelial lymphocytes, chemokine receptors, and pattern recognition receptors promote an abnormal immune response, with increased differentiation of proinflammatory cells and a dysregulated relationship with professional antigen-presenting cells. This review focuses on recent developments in the structure of the epithelium, including a detailed account of the apical junctional complex in addition to the role of the enterocyte in antigen recognition, uptake, processing, and presentation. Recently described cytokines such as interleukin-22 and interleukin-31 are highlighted as is the dysregulation of chemokines and secretory IgA in IBD. Finally, the effect of the intestinal epithelial cell on T effector cell proliferation and differentiation are examined in the context of IBD with particular focus on T regulatory cells and the two-way interaction between the intestinal epithelial cell and certain immune cell populations.
肠上皮不仅作为物理屏障来阻止共生菌和外源性抗原，还积极参与抗原处理和免疫细胞调节。炎症性肠病（IBD）的特征是黏膜表面发生炎症，其屏障和分泌功能明显缺陷。此外，上皮内淋巴细胞、趋化因子受体和模式识别受体的缺陷会促进异常免疫反应，促炎细胞的分化增加，与专业抗原呈递细胞的关系失调。这篇综述重点介绍了上皮结构的最新进展，包括详细描述了顶端连接复合体以及肠细胞在抗原识别、摄取、加工和呈递中的作用。还强调了最近描述的细胞因子，如白细胞介素-22 和白细胞介素-31，以及 IBD 中趋化因子和分泌型 IgA 的失调。最后，在 IBD 的背景下，检查了肠上皮细胞对 T 效应细胞增殖和分化的影响，特别关注 T 调节细胞以及肠上皮细胞与某些免疫细胞群之间的双向相互作用。
