title: T cells and intestinal commensal bacteria--ignorance, rejection, and acceptance.
abstract: Trillions of commensal bacteria cohabit our bodies to mutual benefit. In the past several years, it has become clear that the adaptive immune system is not ignorant of intestinal commensal bacteria, but is constantly interacting with them. For T cells, the response to commensal bacteria does not appear uniform, as certain commensal bacterial species appear to trigger effector T cells to reject and control them, whereas other species elicit Foxp3(+) regulatory T (Treg) cells to accept and be tolerant of them. Here, we review our current knowledge of T cell differentiation in response to commensal bacteria, and how this process leads to immune homeostasis in the intestine.
authors.affiliation: Department of Medicine, Division of Rheumatology, Washington University School of Medicine, St. Louis, MO 63132, United States.
authors.forename: Jiani N
authors.initials: JN
authors.lastname: Chai
authors.affiliation: Department of Medicine, Division of Rheumatology, Washington University School of Medicine, St. Louis, MO 63132, United States.
authors.forename: You W
authors.initials: YW
authors.lastname: Zhou
authors.affiliation: Department of Medicine, Division of Rheumatology, Washington University School of Medicine, St. Louis, MO 63132, United States. Electronic address: chsieh@wustl.edu.
authors.forename: Chyi-Song
authors.initials: CS
authors.lastname: Hsieh
mesh_terms: D056704:Adaptive Immunity; D001402:B-Lymphocytes / Q000276:immunology; D001419:Bacteria; D006706:Homeostasis; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000276:immunology* / Q000382:microbiology*; D013559:Symbiosis; D013601:T-Lymphocytes / Q000276:immunology*
keywords: Commensal; Effector cell; IgA; Inflammatory bowel disease; Intestine; Mucosa; T cell; Tolerance; Treg