Time to face the proofs: the BCG Moreau vaccine promotes superior inflammatory cytokine profile in vitro when compared with Russia, Pasteur, and Danish strains

Tuberculosis (TB) has been a major public health problem worldwide, and the Bacillus Calmette–Guérin (BCG) vaccine is the only available vaccine against this disease. The BCG vaccine is no longer a single organism; it consists of diverse strains. The early-shared strains of the BCG vaccine are stronger immunostimulators than the late-shared strains. In this study, we have employed a simple in vitro human model to broadly evaluate the differences among four widely used BCG vaccines during the characterization of strain-specific host immune responses. In general, the BCG Moreau vaccine generated a higher inflammatory cytokine profile and lower TGF-β levels compared with the Russia, Pasteur, and Danish strains in the context of early sensitization with TB; however, no changes were observed in the IL-23 levels between infected and noninfected cultures. Unsurprisingly, the BCG vaccines provided different features, and the variances among those strains may influence the activation of infected host cells, which ultimately leads to distinct protective efficacy to tackle TB.