Dendritic cells are host cells for mycobacteria in vivo that trigger innate and acquired immunity.
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.
Jiao
Xinan
X
Unité de Biologie des Régulations Immunitaires, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France.
Lo-Man
Richard
R
Guermonprez
Pierre
P
Fiette
Laurence
L
Dériaud
Edith
E
Burgaud
Sophie
S
Gicquel
Brigitte
B
Winter
Nathalie
N
Leclerc
Claude
C
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
D018122:B7-1 Antigen; D001500:BCG Vaccine; D019013:CD40 Antigens; D000949:Histocompatibility Antigens Class II; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic; D018664:Interleukin-12