Rowett Institute of Nutrition & Health, University of Aberdeen, Foresterhill, Aberdeen, Scotland, UK.
Nutr Rev. 2012 Aug;70 Suppl 1:S18-30. doi: 10.1111/j.1753-4887.2012.00498.x.
The healthy human gut supports a complex and diverse microbiota, dominated by bacterial phylotypes belonging to Bacteroidetes and Firmicutes. In the inflamed gut, overall diversity decreases, coincident with a greater representation of Proteobacteria. There is growing evidence supporting an important role for human gut bacteria in mucosal immunity; interactions at the level of both intestinal and colonic epithelial cells, dendritic cells, and T and B immune cells have been documented. These interactions influence gut barrier and defense mechanisms that include antimicrobial peptide and secretory IgA synthesis. The functional effects of commensal bacteria on T helper cell differentiation have led to the emerging concept that microbiota composition determines T effector- and T regulatory-cell balance, immune responsiveness, and homeostasis. The importance of this biology in relation to immune homeostasis, inflammatory bowel disease, and the rising incidence of autoimmune diseases will be discussed. The detailed description of the human gut microbiota, integrated with evidence-based mechanisms of immune modulation, provides an exciting platform for the identification of next-generation probiotics and related pharmaceutical products.
健康的人类肠道支持着复杂多样的微生物群落，其中以厚壁菌门和拟杆菌门的细菌型为主导。在发炎的肠道中，总体多样性减少，同时变形菌门的代表性增加。越来越多的证据支持人类肠道细菌在黏膜免疫中发挥重要作用；在肠道和结肠上皮细胞、树突状细胞以及 T 和 B 免疫细胞的水平上都有相互作用的记录。这些相互作用影响肠道屏障和防御机制，包括抗菌肽和分泌型 IgA 的合成。共生细菌对辅助性 T 细胞分化的功能影响导致了一个新兴概念的出现，即微生物群落组成决定了 T 效应细胞和 T 调节细胞的平衡、免疫反应性和体内平衡。将这种生物学与免疫体内平衡、炎症性肠病和自身免疫性疾病发病率上升的关系进行讨论具有重要意义。与免疫调节的循证机制相结合，对人类肠道微生物组的详细描述为新一代益生菌和相关药物产品的鉴定提供了一个令人兴奋的平台。
