title: Induction of protective IgA by intestinal dendritic cells carrying commensal bacteria.
abstract: The enormous number of commensal bacteria in the lower intestine of vertebrates share abundant molecular patterns used for innate immune recognition of pathogenic bacteria. We show that, even though commensals are rapidly killed by macrophages, intestinal dendritic cells (DCs) can retain small numbers of live commensals for several days. This allows DCs to selectively induce IgA, which helps protect against mucosal penetration by commensals. The commensal-loaded DCs are restricted to the mucosal immune compartment by the mesenteric lymph nodes, which ensures that immune responses to commensal bacteria are induced locally, without potentially damaging systemic immune responses.
authors.affiliation: Institute of Experimental Immunology, Universitätsspital, CH8091 Zürich, Switzerland. amacpher@pathol.unizh.ch
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Macpherson
authors.forename: Therese
authors.initials: T
authors.lastname: Uhr
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D001402:B-Lymphocytes / Q000276:immunology; D001419:Bacteria / Q000254:growth & development / Q000276:immunology* / Q000302:isolation & purification; D003713:Dendritic Cells / Q000276:immunology* / Q000382:microbiology*; D016972:Enterobacter cloacae / Q000254:growth & development / Q000276:immunology / Q000302:isolation & purification; D005856:Germ-Free Life; D007113:Immunity, Innate; D018928:Immunity, Mucosal; D007070:Immunoglobulin A / Q000096:biosynthesis* / Q000097:blood / Q000276:immunology; D007413:Intestinal Mucosa / Q000276:immunology* / Q000382:microbiology; D007422:Intestines / Q000382:microbiology*; D007962:Leukocytes / Q000276:immunology / Q000382:microbiology; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology / Q000382:microbiology; D008264:Macrophages / Q000276:immunology / Q000382:microbiology; D008643:Mesentery; D051379:Mice; D008810:Mice, Inbred C57BL; D010581:Peyer's Patches / Q000166:cytology / Q000276:immunology; D010587:Phagocytosis; D012486:Salmonella typhimurium / Q000254:growth & development / Q000276:immunology / Q000302:isolation & purification; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000166:cytology / Q000382:microbiology
chemical_list: D007070:Immunoglobulin A