IL-10 receptor blockade delivered simultaneous with BCG vaccination sustains long term protection against Mycobacterium tuberculosis infection in mice

Mycobacterium bovis bacillus Calmette-Guerin (BCG) immunization still remains the best vaccination strategy available to control the development of active tuberculosis (TB). Protection afforded by BCG vaccination gradually wanes over time and while booster strategies have promise, they remain under development. An alternative approach is to improve BCG efficacy through host-directed therapy. Building upon prior knowledge that blockade of interleukin-10 receptor 1 (IL-10R1) during early Mycobacterium tuberculosis (M.tb) infection improves and extends control of M.tb infection in mice, we employed a combined anti-IL-10R1/BCG vaccine strategy. A subcutaneous, single vaccination of BCG/αIL10-R1 increased the numbers of CD4+ and CD8+ central memory T cells, and reduced TH1 and TH17 cytokine levels in the lung for up to 7 weeks post vaccination. Subsequent M.tb challenge in mice showed both an early (4 week) and sustained long-term (47 week) control of infection, which was associated with increased survival. In contrast, protection of BCG/saline vaccinated mice waned 8 weeks post M.tb infection. Our findings demonstrate that a single and simultaneous vaccination with BCG/αIL10-R1 sustains long-term protection, identifying a promising approach to enhance and extend the current BCG mediated protection against TB.