title: Functions of innate immune cells and commensal bacteria in gut homeostasis.
abstract: The intestinal immune system remains unresponsive to beneficial microbes and dietary antigens while activating pro-inflammatory responses against pathogens for host defence. In intestinal mucosa, abnormal activation of innate immunity, which directs adaptive immune responses, causes the onset and/or progression of inflammatory bowel diseases. Thus, innate immunity is finely regulated in the gut. Multiple innate immune cell subsets have been identified in both murine and human intestinal lamina propria. Some innate immune cells play a key role in the maintenance of gut homeostasis by preventing inappropriate adaptive immune responses while others are associated with the pathogenesis of intestinal inflammation through development of Th1 and Th17 cells. In addition, intestinal microbiota and their metabolites contribute to the regulation of innate/adaptive immune responses. Accordingly, perturbation of microbiota composition can trigger intestinal inflammation by driving inappropriate immune responses.
authors.affiliation: Laboratory of Immune Regulation, Department of Microbiology and Immunology, Graduate School of Medicine and Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Hisako
authors.initials: H
authors.lastname: Kayama
authors.affiliation: Laboratory of Immune Regulation, Department of Microbiology and Immunology, Graduate School of Medicine and Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan ktakeda@ongene.med.osaka-u.ac.jp.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Takeda
mesh_terms: D000818:Animals; D001419:Bacteria / Q000276:immunology* / Q000378:metabolism; D000069196:Gastrointestinal Microbiome / Q000276:immunology*; D006706:Homeostasis; D006801:Humans; D007113:Immunity, Innate; D007249:Inflammation / Q000276:immunology; D015212:Inflammatory Bowel Diseases / Q000276:immunology*; D007413:Intestinal Mucosa / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D051379:Mice; D018417:Th1 Cells / Q000276:immunology; D058504:Th17 Cells / Q000276:immunology
keywords: adaptive immunity; commensal bacteria; gut homeostasis; inflammatory bowel disease; innate immunity