rBCG::PUMA exhibits enhanced immunogenicity compared to BCG in mice

Background Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains a major global public health threat. The limited efficacy of the current Bacillus Calmette-Guérin (BCG) vaccine against adult pulmonary TB highlights the urgent need for improved vaccine strategies. To address this, we engineered a recombinant BCG strain, designated rBCG::PUMA, which expresses the pro-apoptotic gene PUMA to enhance immunogenicity. Results In mouse models, rBCG::PUMA infection was associated with significantly increased macrophage apoptosis in vitro (p + central memory T cells (TCM) at week 8 post-immunization and elevated CD4 + effector memory T cells (TEM), and was associated with sustained upregulation of macrophage costimulatory molecules at week 12 (P Conclusion Enhancement of the apoptotic pathway via PUMA was associated with broader and enhanced immunogenicity of rBCG::PUMA in mice compared with conventional BCG. This included improved cellular immunity, enhanced generation of memory T cell subsets, enhanced macrophage costimulatory activity, and stronger humoral responses, while maintaining a favorable safety profile. However, this study did not include a Mycobacterium tuberculosis challenge model; therefore, protective efficacy remains to be determined. These findings provide a preliminary immunological basis for further evaluation of rBCG::PUMA as a promising immunogenic platform and support the concept of apoptosis-targeted vaccine design.