Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA.
Expert Rev Anti Infect Ther. 2012 Mar;10(3):391-400. doi: 10.1586/eri.11.176.
The intestinal epithelium provides a barrier between a variety of luminal antigens and provides the components of intestinal innate and adaptive immunity. It is crucial that at this interface, the epithelial cell layer and the components of the intestinal immunity interact with dietary and bacterial antigens in a regulated way to maintain homeostasis. Failure to tightly control immune reactions can be detrimental and result in inflammation. In the current review, we described the regulatory mechanisms controlling host-immune homeostasis and the role of regulatory CD4(+) T cells, with a special emphasis in the regulatory T-cell subsets (Tregs). Furthermore, the participation of innate cell cross-talk in the polarization of intestinal immune responses is also evaluated. Finally, the recent characterization of host responses to normal commensal flora, the role of bacteria and bacterial factors in the maintenance of immunomodulation, and the disruption of this balance by bacterial enteric pathogens is also summarized.
肠上皮为多种腔抗原提供了一道屏障，并为肠道先天和适应性免疫提供了组成部分。至关重要的是，在这个界面上，上皮细胞层和肠道免疫的组成部分以受调控的方式与膳食和细菌抗原相互作用，以维持体内平衡。如果不能严格控制免疫反应，就可能造成损害并导致炎症。在本综述中，我们描述了控制宿主-免疫稳态的调节机制以及调节性 CD4(+) T 细胞的作用，特别强调了调节性 T 细胞亚群（Tregs）的作用。此外，还评估了固有细胞串扰在肠道免疫反应极化中的作用。最后，还总结了宿主对正常共生菌群的反应、细菌及其因子在维持免疫调节中的作用，以及细菌肠道病原体对这种平衡的破坏。
