Recombinant bacille Calmette–Guerin coexpressing Ag85b, CFP10, and interleukin-12 elicits effective protection against Mycobacterium tuberculosis

Background The tuberculosis (TB) pandemic remains a leading cause of human morbidity and mortality, despite widespread use of the only licensed anti-TB vaccine, bacille Calmette-Guerin (BCG). The protective efficacy of BCG in preventing pulmonary TB is highly variable; therefore, an effective new vaccine is urgently required. Methods In the present study, we assessed the ability of novel recombinant BCG vaccine (rBCG) against Mycobacterium tuberculosis by using modern immunological methods. Results Enzyme-linked immunospot assays demonstrated that the rBCG vaccine, which coexpresses two mycobacterial antigens (Ag85B and CFP10) and human interleukin (IL)-12 (rBCG2) elicits greater interferon-γ (IFN-γ) release in the mouse lung and spleen, compared to the parental BCG. In addition, rBCG2 triggers a Th1-polarized response. Our results also showed that rBCG2 vaccination significantly limits M. tuberculosis H37Rv multiplication in macrophages. The rBCG2 vaccine surprisingly induces significantly higher tumor necrosis factor-α (TNF-α) production by peripheral blood mononuclear cells that were exposed to a nonmycobacterial stimulus, compared to the parental BCG. Conclusion In this study, we demonstrated that the novel rBCG2 vaccine may be a promising candidate vaccine against M. tuberculosis infection.