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Granuloma correlates of protection against tuberculosis and mechanisms of immune modulation by Mycobacterium tuberculosis.

Authors :
Mehra S
Alvarez X
Didier PJ
Doyle LA
Blanchard JL
Lackner AA
Kaushal D
Source :
The Journal of infectious diseases [J Infect Dis] 2013 Apr; Vol. 207 (7), pp. 1115-27. Date of Electronic Publication: 2012 Dec 18.
Publication Year :
2013

Abstract

Background: The BCG vaccine is ineffective against adult tuberculosis. Hence, new antituberculosis vaccines are needed. Correlates of protection against tuberculosis are not known. We studied the effects of BCG vaccination on gene expression in tuberculosis granulomas using macaques.<br />Methods: Macaques were BCG-vaccinated or sham-vaccinated and then challenged with virulent Mycobacterium tuberculosis. Lung lesions were used for comparative transcriptomics.<br />Results: Vaccinated macaques were protected with lower bacterial burden and immunopathology. Lesions from BCG-vaccinated nonhuman primates (NHPs) showed a better balance of α- and β-chemokine gene expression with higher levels of β-chemokine expression relative to nonvaccinated animals. Consistent with this, sham-vaccinated macaques recruited fewer macrophages relative to neutrophils in their lungs. The expression of indoleamine 2,3-dioxygenase (IDO), a known immunosuppressor, was significantly higher in both week 5 and 10 lesions from sham-vaccinated, relative to BCG-vaccinated, NHPs. IDO expression was primarily limited to the nonlymphocytic region of the lesions, within the inner ring structure surrounding the central necrosis.<br />Conclusions: Our study defines lung gene expression correlates of protective response against tuberculosis, relative to disease, which can potentially be employed to assess the efficacy of candidate antituberculosis vaccines. Mycobacterium tuberculosis may modulate protective immune responses using diverse mechanisms, including increased recruitment of inflammatory neutrophils and the concomitant use of IDO to modulate inflammation.

Details

Language :
English
ISSN :
1537-6613
Volume :
207
Issue :
7
Database :
MEDLINE
Journal :
The Journal of infectious diseases
Publication Type :
Academic Journal
Accession number :
23255564
Full Text :
https://doi.org/10.1093/infdis/jis778