Design of a multi-epitope vaccine against drug-resistant mycobacterium tuberculosis and mycobacterium bovis using reverse vaccinology

The global burden of Mycobacterium tuberculosis (M. tuberculosis) and Mycobacterium bovis (M. bovis), the rise of drug-resistant strains, necessitates an urgent need for developing more effective vaccines. This study employed an in-silico approach to design a multi-epitope vaccine targeting the PE_PGRS16 protein, a conserved virulence factor found across both species, including drug-resistant strains. PE_PGRS16 was chosen due to its extracellular localization, adhesion properties, and virulence characteristics, making it a promising vaccine target. Epitopes for B-cells, Cytotoxic T Lymphocytes, and Helper T Lymphocytes were selected based on antigenicity, non-toxicity, and immune response potential. The vaccine construct demonstrated favorable properties, including high antigenicity, solubility, and stability, with a low instability index (-31.31) and binding energy (-44.566) when docked to TLR4, suggesting its potential for immune activation. Griselimycin was incorporated as an adjuvant to enhance immunogenicity, as predicted by C-ImmSim simulations. Population coverage analysis for East Africa revealed high applicability, with 98.35% coverage for Class I epitopes, 100% coverage for Class II epitopes, and 100% combined coverage, with average hit values of 8.4, 12.26, and 20.66, respectively. These results suggest broad potential for global vaccine deployment. This study presents a novel multi-epitope vaccine targeting PE_PGRS16, with the potential to combat Mycobacterium tuberculosis and Mycobacterium bovis infections, including drug-resistant forms. Further experimental validation is necessary to confirm its efficacy and safety.