title: Microbiota: host interactions in mucosal homeostasis and systemic autoimmunity.
abstract: The vertebrate intestinal tract is colonized by hundreds of species of bacteria that must be compartmentalized and tolerated to prevent invasive growth and harmful inflammatory responses. Signaling initiated by commensal bacteria shapes antigen-specific mucosal and systemic adaptive immunity. A distinct type of effector CD4(+) T cells, Th17 cells, have a key role in coordinating the inflammatory immune responses that afford protection to pathogens at the mucosal interface. Balancing this powerful inflammatory response, regulatory T cells limit collateral damage and provide antigen-specific tolerance to both food and microbial antigens. Here, we discuss the implications for how the microbiota as a whole contributes to compartmentalization from the host and how individual constituents of the microbiota influence the functions and repertoire of effector T cells and organ-specific autoimmune disease.
authors.affiliation: The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, New York 10016 The Jill Roberts Center for Inflammatory Bowel Disease, Department of Medicine, Weill-Cornell Medical College, New York, New York 10021.
authors.forename: Randy S
authors.initials: RS
authors.lastname: Longman
authors.affiliation: The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, New York 10016.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.affiliation: The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, New York 10016.
authors.forename: Gretchen E
authors.initials: GE
authors.lastname: Diehl
authors.affiliation: The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, New York 10016.
authors.forename: Sangwon V
authors.initials: SV
authors.lastname: Kim
authors.affiliation: The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, New York 10016 Howard Hughes Medical Institute, New York University School of Medicine, New York, New York 10016 dan.littman@med.nyu.edu.
authors.forename: Dan R
authors.initials: DR
authors.lastname: Littman
mesh_terms: D000818:Animals; D015551:Autoimmunity; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology; D006706:Homeostasis; D006801:Humans; D007108:Immune Tolerance; D007249:Inflammation; D007422:Intestines / Q000276:immunology / Q000382:microbiology*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D051379:Mice; D064307:Microbiota; D009092:Mucous Membrane / Q000276:immunology*; D010586:Phagocytes; D050378:T-Lymphocytes, Regulatory / Q000166:cytology; D058504:Th17 Cells / Q000166:cytology