Elsevier

Mucosal Immunology

Volume 5, Issue 4, July 2012, Pages 420-431
Mucosal Immunology

Article
Mechanisms of delayed anti-tuberculosis protection in the lung of parenteral BCG-vaccinated hosts: A critical role of airway luminal T cells

https://doi.org/10.1038/mi.2012.19Get rights and content
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Abstract

The immune mechanisms underlying unsatisfactory pulmonary mucosal protection by parenteral Bacillus Calmette–Guérin (BCG) immunization remain poorly understood. We found that parenteral BCG immunization failed to elicit airway luminal T cells (ALT) whereas it induced significant T cells in the lung interstitium. After Mycobacterium tuberculosis (M.tb) challenge, ALT remained missing for 10 days. The lack of ALT correlated with lack of lung protection for 14 days post-M.tb challenge. To further investigate the role of ALT, ALT were elicited in BCG-immunized animals by intranasal inoculation of M.tb culture-filtrate (CF) proteins. Installment of ALT by CF restored protection in the early phases of M.tb infection, which was linked to rapid increases in ALT, but not in lung interstitial T cells. Also, adoptive transfer of T cells to the airway lumen of BCG-immunized animals also accelerated protection. This study thus provides novel evidence that unsatisfactory lung protection by parenteral BCG immunization is due to delayed ALT recruitment after pulmonary M.tb exposure.

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Published online: 28 3 2012

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Supplementary information The online version of this article (doi:10.1038/mi.2012.19) contains supplementary material, which is available to authorized users.