Pulmonary MTBVAC vaccination induces immune signatures previously correlated with prevention of tuberculosis infection

Summary To fight tuberculosis, better vaccination strategies are needed. Live attenuated Mycobacterium tuberculosis-derived vaccine, MTBVAC, is a promising candidate in the pipeline, proven to be safe and immunogenic in humans so far. Independent studies have shown that pulmonary mucosal delivery of Bacillus Calmette-Guérin (BCG), the only tuberculosis (TB) vaccine available today, confers superior protection over standard intradermal immunization. Here we demonstrate that mucosal MTBVAC is well tolerated, eliciting polyfunctional T helper type 17 cells, interleukin-10, and immunoglobulins in the airway and yielding a broader antigenic profile than BCG in rhesus macaques. Beyond our previous work, we show that local immunoglobulins, induced by MTBVAC and BCG, bind to M. tuberculosis and enhance pathogen uptake. Furthermore, after pulmonary vaccination, but not M. tuberculosis infection, local T cells expressed high levels of mucosal homing and tissue residency markers. Our data show that pulmonary MTBVAC administration has the potential to enhance its efficacy and justifies further exploration of mucosal vaccination strategies in preclinical efficacy studies.
Graphical Abstract
Highlights Pulmonary MTBVAC delivery confers immune signature correlating with TB protection This signature spreads through the lung without a recall response in the skin Vaccine-induced T cells have increased mucosal homing and tissue residency markers Vaccine-induced antibodies enhance phagocytosis of M. tuberculosis
Dijkman et al. show that pulmonary immunization with the M. tuberculosis-derived vaccine candidate MTBVAC confers a local mucosal antigen-specific signature—polyfunctional Th1/Th17 cells exhibiting increased homing and tissue residency marker expression, IL-10, and phagocytosis-promoting immunoglobulins—that has been associated previously with protection from TB infection and disease in rhesus macaques.