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Am J Pathol. 2014 Jul;184(7):2045-55. doi: 10.1016/j.ajpath.2014.03.008. Epub 2014 May 9.

Characterization of a novel necrotic granuloma model of latent tuberculosis infection and reactivation in mice.

Author information

1
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.
2
Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
3
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland. Electronic address: petros@jhmi.edu.

Abstract

We sought to develop and characterize a novel paucibacillary model in mice, which develops necrotic lung granulomas after infection with Mycobacterium tuberculosis. Six weeks after aerosol immunization with recombinant Mycobacterium bovis bacillus Calmette-Guerin overexpressing the 30-kDa antigen, C3HeB/FeJ mice were aerosol infected with M. tuberculosis H37Rv. Six weeks later, mice were treated with one of three standard regimens for latent tuberculosis infection or tumor necrosis factor (TNF)-neutralizing antibody. Mouse lungs were analyzed by histological features, positron emission tomography/computed tomography, whole-genome microarrays, and RT-PCR. Lungs and sera were studied by multiplex enzyme-linked immunosorbent assays. Paucibacillary infection was established, recapitulating the sterilizing activities of human latent tuberculosis infection regimens. TNF neutralization led to increased lung bacillary load, disrupted granuloma architecture with expanded necrotic foci and reduced tissue hypoxia, and accelerated animal mortality. TNF-neutralized mouse lungs and sera showed significant up-regulation of interferon γ, IL-1β, IL-6, IL-10, chemokine ligands 2 and 3, and matrix metalloproteinase genes. Clinical and microbiological reactivation of paucibacillary infection by TNF neutralization was associated with reduced hypoxia in lung granulomas and induction of matrix metalloproteinases and proinflammatory cytokines. This model may be useful for screening the sterilizing activity of novel anti-tuberculosis drugs, and identifying mycobacterial regulatory and metabolic pathways required for bacillary growth restriction and reactivation.

PMID:
24815353
PMCID:
PMC4076462
DOI:
10.1016/j.ajpath.2014.03.008
[Indexed for MEDLINE]
Free PMC Article

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