The potential role of lung epithelial cells and beta-defensins in experimental latent tuberculosis.
Mycobacterium tuberculosis is a facultative intracellular pathogen capable of producing both progressive disease and latent infection. Latent infection is clinically asymptomatic and is manifested only by a positive tuberculin test or a chest radiograph that shows scars or calcified nodules indicative of resolved primary tuberculosis infection. In this study, we used a well-characterized model of latent tuberculosis infection in B6D2F1 mice to compare the production of beta-defensin-3 by infected bronchial epithelial cells and macrophages. We demonstrated by immunolectronmicroscopy that M. tuberculosis can actually infect epithelial cells and induce significant higher production of beta-defensin-3 associated to mycobacteria than infected macrophages. These results demonstrate that lung epithelium harbour mycobacteria during experimental chronic infection; being a possible reservoir of latent mycobacteria in vivo, beta-defensins might participate in bacilli killing or dormancy induction.
Rivas-Santiago
B
B
Medical Research Unit-Zacatecas, IMSS, Zacatecas, Mexico.
Contreras
J C L
JC
Sada
E
E
Hernández-Pando
R
R
D000818:Animals; D030801:Animals, Genetically Modified; D001980:Bronchi / Q000276:immunology / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism* / Q000382:microbiology; D005260:Female; D008264:Macrophages / Q000378:metabolism / Q000382:microbiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D016253:Microscopy, Immunoelectron; D009169:Mycobacterium tuberculosis; D014397:Tuberculosis, Pulmonary / Q000378:metabolism* / Q000382:microbiology; D023083:beta-Defensins / Q000378:metabolism*
C422950:DEFB103A protein, human; D023083:beta-Defensins