Laboratory of Immune Regulation, Department of Microbiology and Immunology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan.
Int Immunol. 2012 Nov;24(11):673-80. doi: 10.1093/intimm/dxs094. Epub 2012 Sep 7.
The intestine is a unique tissue where an elaborate balance is maintained between tolerance and immune responses against a variety of environmental factors such as food and the microflora. In a healthy individual, the microflora stimulates innate and adaptive immune systems to maintain gut homeostasis. However, the interaction of environmental factors with particular genetic backgrounds can lead to dramatic changes in the composition of the microflora (i.e. dysbiosis). Many of the specific commensal-bacterial products and the signaling pathways they trigger have been characterized. The role of T(h)1, T(h)2 and T(h)17 cells in inflammatory bowel disease has been widely investigated, as has the contribution of epithelial cells and subsets of dendritic cells and macrophages. To date, multiple regulatory cells in adaptive immunity, such as regulatory T cells and regulatory B cells, have been shown to maintain gut homeostasis by preventing inappropriate innate and adaptive immune responses to commensal bacteria. Additionally, regulatory myeloid cells have recently been identified that prevent intestinal inflammation by inhibiting T-cell proliferation. An increasing body of evidence has shown that multiple regulatory mechanisms contribute to the maintenance of gut homeostasis.
肠道是一种独特的组织，其中耐受和免疫反应之间存在着精细的平衡，以应对各种环境因素，如食物和微生物群落。在健康个体中，微生物群落刺激先天和适应性免疫系统以维持肠道内稳态。然而，环境因素与特定遗传背景的相互作用可能导致微生物群落组成的剧烈变化（即失调）。许多特定的共生细菌产物及其触发的信号通路已被阐明。Th1、Th2 和 Th17 细胞在炎症性肠病中的作用已被广泛研究，上皮细胞以及树突状细胞和巨噬细胞的亚群的作用也已被研究。迄今为止，适应性免疫中的多种调节细胞，如调节性 T 细胞和调节性 B 细胞，已被证明通过防止对共生细菌的不适当先天和适应性免疫反应来维持肠道内稳态。此外，最近已经鉴定出调节性髓样细胞，它们通过抑制 T 细胞增殖来预防肠道炎症。越来越多的证据表明，多种调节机制有助于维持肠道内稳态。
