Laboratory for Mucosal Immunity, Center for Integrative Medical Sciences IMS-RCAI, RIKEN Yokohama Institute, Yokohama, Japan.
Immunol Cell Biol. 2014 Jan;92(1):49-56. doi: 10.1038/icb.2013.54. Epub 2013 Oct 8.
The main function of the immune system is to protect the host against pathogens. However, unlike the systemic immune system, the gut immune system does not eliminate, but instead nourishes complex bacterial communities and establishes advanced symbiotic relationships. Immunoglobulin A (IgA) is the most abundant antibody isotype in mammals, produced mainly in the gut. The primary function of IgA is to maintain homeostasis at mucosal surfaces, and studies in mice have demonstrated that IgA diversification has an essential role in the regulation of gut microbiota. Dynamic diversification and constant adaptation of IgA responses to local microbiota require expression of activation-induced cytidine deaminase by B cells and control from T follicular helper and Foxp3(+) T cells in germinal centers (GCs). We discuss the finely tuned regulatory mechanisms for IgA synthesis in GCs of Peyer's patches and emphasize the roles of CD4(+) T cells for IgA selection and the maintenance of appropriate gut microbial communities required for immune homeostasis.
免疫系统的主要功能是保护宿主免受病原体的侵害。然而，与系统性免疫系统不同，肠道免疫系统不会消除，而是滋养复杂的细菌群落，并建立先进的共生关系。免疫球蛋白 A（IgA）是哺乳动物中最丰富的抗体同种型，主要在肠道中产生。IgA 的主要功能是维持粘膜表面的内稳态，小鼠研究表明，IgA 多样化在调节肠道微生物群中起着至关重要的作用。IgA 对局部微生物群的反应的动态多样化和持续适应需要 B 细胞表达激活诱导的胞苷脱氨酶，并在生发中心（GC）中受滤泡辅助性 T 细胞和 Foxp3(+)T 细胞的控制。我们讨论了派尔集合淋巴结中 IgA 合成的精细调控机制，并强调了 CD4(+)T 细胞在 IgA 选择和维持免疫内稳态所需的适当肠道微生物群落中的作用。
