Mycobacterium tuberculosis infects dendritic cells with high frequency and impairs their function in vivo.
Mycobacterium tuberculosis (Mtb) is thought to reside in macrophages, although infected dendritic cells (DCs) have been observed. Thus, although cellular associations have been made, global characterization of the cells harboring Mtb is lacking. We have performed temporal and quantitative characterization of the cells harboring Mtb following aerosol infection of mice by using GFP-expressing bacteria and flow cytometry. We discovered that Mtb infects phagocytic cells of diverse phenotypes, that the predominant infected cell populations change with time, and that myeloid DCs are the major cell population infected with Mtb in the lungs and lymph nodes. We also found that the bacteria in the lung-draining lymph node are transported there from the lungs by a CCL19/21-dependent mechanism and that the transport of bacteria to the lymph node is a transient phenomenon despite chronic infection. In addition, we found that the lymph node cell subsets that are most efficacious in stimulating Mtb-specific, TCR-transgenic CD4(+) T lymphocytes are not infected with the bacteria and are scarce or absent from the lungs of infected mice. Finally, we found that the lung cell populations that are infected with Mtb at high frequency are relatively ineffective at stimulating Ag-specific CD4(+) T lymphocytes, and we have obtained evidence that live Mtb can inhibit MHC class II Ag presentation without a decrease in the surface expression of MHC class II. These results indicate that Mtb targets DC migration and Ag presentation in vivo to promote persistent infection.
Division of Infectious Diseases, Department of Medicine, New York University School of Medicine, New York, NY 10016, USA.
Andrea J
AJ
Wolf
Beth
B
Linas
Giraldina J
GJ
Trevejo-Nuñez
Eleanor
E
Kincaid
Toshiki
T
Tamura
Kiyoshi
K
Takatsu
Joel D
JD
Ernst
D000818:Animals; D017951:Antigen Presentation / Q000235:genetics / Q000276:immunology*; D001693:Biological Transport, Active / Q000235:genetics / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D002465:Cell Movement / Q000235:genetics / Q000276:immunology; D054415:Chemokine CCL19; D054421:Chemokine CCL21; D019742:Chemokines, CC / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000276:immunology; D008168:Lung / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D008198:Lymph Nodes / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D008264:Macrophages / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D051379:Mice; D008822:Mice, Transgenic; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000276:immunology; D014397:Tuberculosis, Pulmonary / Q000276:immunology* / Q000473:pathology / Q000662:veterinary
C515461:Ccl19 protein, mouse; C515481:Ccl21b protein, mouse; D054415:Chemokine CCL19; D054421:Chemokine CCL21; D019742:Chemokines, CC; D000949:Histocompatibility Antigens Class II; D011948:Receptors, Antigen, T-Cell; D049452:Green Fluorescent Proteins