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Gut T FH and IgA: key players for regulation of bacterial communities and immune homeostasis
Author(s) -
Kato Lucia M,
Kawamoto Shimpei,
Maruya Mikako,
Fagarasan Sidonia
Publication year - 2014
Publication title -
immunology and cell biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0818-9641
DOI - 10.1038/icb.2013.54
Subject(s) - homeostasis , immune system , key (lock) , biology , immunology , microbiology and biotechnology , ecology
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.