title: Dendritic cells are host cells for mycobacteria in vivo that trigger innate and acquired immunity.
abstract: In the present study, we investigated in vivo the infection and APC functions of dendritic cells (DC) and macrophages (Mphi) after administration of live mycobacteria to mice. Experiments were conducted with Mycobacterium bovis bacillus Calmette-Guerin (BCG) or a rBCG expressing a reporter Ag. Following infection of mice, DC and Mphi were purified and the presence of immunogenic peptide/MHC class II complexes was detected ex vivo on sorted cells, as was the secretion of IL-12 p40. We show in this study that DC is a host cell for mycobacteria, and we provide an in vivo detailed picture of the role of Mphi and DC in the mobilization of immunity during the early stages of a bacterial infection. Strikingly, BCG bacilli survive but remain stable in number in the DC leukocyte subset during the first 2 wk of infection. As Ag presentation by DC is rapidly lost, this suggests that DC may represent a hidden reservoir for mycobacteria.
authors.affiliation: Unité de Biologie des Régulations Immunitaires, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France.
authors.forename: Xinan
authors.initials: X
authors.lastname: Jiao
authors.forename: Richard
authors.initials: R
authors.lastname: Lo-Man
authors.forename: Pierre
authors.initials: P
authors.lastname: Guermonprez
authors.forename: Laurence
authors.initials: L
authors.lastname: Fiette
authors.forename: Edith
authors.initials: E
authors.lastname: Dériaud
authors.forename: Sophie
authors.initials: S
authors.lastname: Burgaud
authors.forename: Brigitte
authors.initials: B
authors.lastname: Gicquel
authors.forename: Nathalie
authors.initials: N
authors.lastname: Winter
authors.forename: Claude
authors.initials: C
authors.lastname: Leclerc
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D018122:B7-1 Antigen / Q000032:analysis / Q000096:biosynthesis; D001500:BCG Vaccine / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D019013:CD40 Antigens / Q000032:analysis / Q000096:biosynthesis; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology*; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000032:analysis / Q000096:biosynthesis; D007110:Immunity, Active; D007113:Immunity, Innate; D007115:Immunization Schedule; D016130:Immunophenotyping; D007275:Injections, Intravenous; D018664:Interleukin-12 / Q000096:biosynthesis; D008264:Macrophages / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D009163:Mycobacterium bovis / Q000254:growth & development / Q000276:immunology*; D014376:Tuberculosis / Q000276:immunology* / Q000382:microbiology*; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology
chemical_list: D018122:B7-1 Antigen; D001500:BCG Vaccine; D019013:CD40 Antigens; D000949:Histocompatibility Antigens Class II; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic; D018664:Interleukin-12