title: The continuum of intestinal CD4+ T cell adaptations in host-microbial mutualism.
abstract: How a mutualistic relationship between the intestinal microbiota and intestinal T cell compartments is established is important, as a breakdown of intestinal T cell homeostasis may cause inflammatory bowel diseases. A number of studies have shown that different bacterial species modulate the intestinal CD4(+) T cell compartment in different ways. We performed mechanistic in vivo studies that demonstrated the crucial requirement for regulatory T cells (Treg) and interleukin-10 (IL-10) in the induction of intestinal T cell homeostasis even following colonization with a completely benign microbiota. In the absence of a functional Treg response or IL-10 receptor signaling, the same bacteria that induced a Treg response in wild-type animals now induced T helper type 17 responses, without intestinal inflammation. Therefore, Treg, IL-10 and Th17 are crucial regulatory mechanisms in the intestine not only for controlling inflammation, but also to establish a continuum of CD4(+) T cell homeostasis upon commensal colonization.
authors.affiliation: Maurice Müller Laboratories, DKF, Bern, Switzerland. markus.geuking@dkf.unibe.ch
authors.forename: Markus B
authors.initials: MB
authors.lastname: Geuking
authors.forename: Kathy D
authors.initials: KD
authors.lastname: McCoy
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Macpherson
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001439:Bacteroides / Q000254:growth & development / Q000276:immunology; D004195:Disease Models, Animal; D006706:Homeostasis; D007111:Immunity, Cellular; D018928:Immunity, Mucosal; D015212:Inflammatory Bowel Diseases / Q000276:immunology / Q000382:microbiology; D016753:Interleukin-10 / Q000276:immunology*; D007422:Intestines / Q000276:immunology / Q000382:microbiology*; D007778:Lactobacillus / Q000254:growth & development / Q000276:immunology; D054892:Metagenome; D051379:Mice; D013047:Specific Pathogen-Free Organisms / Q000276:immunology; D013559:Symbiosis; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000382:microbiology; D058504:Th17 Cells / Q000276:immunology* / Q000382:microbiology
chemical_list: C556062:IL10 protein, mouse; D016753:Interleukin-10