title: Dynamic interactions between bacteria and immune cells leading to intestinal IgA synthesis.
abstract: The gastrointestinal tract is colonized by an immense number of bacteria that are in a constant dialog with our immune cells. One obvious question is how the mucosal immune system maintains a state of hypo-responsiveness toward the commensal bacteria and a state of readiness that allows efficient and prompt responses against pathogens. The answers have important implications for immunologists who seek to understand the fundamental aspects of bacteria-immune cell interactions in the steady-state condition and wish to elucidate the patho-physiologic mechanisms in immune disregulations, such as inflammatory bowel diseases. An important adjustment of the immune system to bacterial colonization of the gut is the "constitutive" production of IgA by the gut-associated lymphoid tissues (GALT). In this review, we summarize the sites and mechanisms for IgA synthesis in mice. We emphasize the important role played by secretory IgAs in maintenance of an appropriate intestinal microbiota, which is required for local and systemic immune homeostasis.
authors.affiliation: Laboratory for Mucosal Immunity, RIKEN Research Center for Allergy and Immunology, 230-0045 Tsurumi, Yokohama, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Tsuji
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Suzuki
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kinoshita
authors.forename: Sidonia
authors.initials: S
authors.lastname: Fagarasan
mesh_terms: D000818:Animals; D016175:B-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology*; D001419:Bacteria / Q000276:immunology* / Q000472:pathogenicity; D002450:Cell Communication / Q000276:immunology; D054884:Host-Pathogen Interactions / Q000276:immunology; D006801:Humans; D018928:Immunity, Mucosal; D007071:Immunoglobulin A, Secretory / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D007413:Intestinal Mucosa / Q000276:immunology* / Q000382:microbiology; D051379:Mice; D010581:Peyer's Patches / Q000276:immunology
chemical_list: D007071:Immunoglobulin A, Secretory