Induction of strong immune response against a multicomponent antigen of Mycobacterium tuberculosis in BALB/c mice using PLGA and DOTAP adjuvant

A promising strategy for preventing illness and death caused by Mycobacterium tuberculosis (Mtb) is vaccination. In this study, we aimed to evaluate the capacity of a multicomponent vaccine comprising HspX/EsxS‐fused protein, PLGA (poly (lactide‐co‐glycolide)) and DOTAP (1, 2‐dioleoyl‐3‐trimethylammonium propane) in eliciting immune responses against Mtb in BALB/c mice. A preparation of PLGA nanoparticles (NPs) containing fused protein and DOTAP adjuvant was made using double emulsion solvent evaporation (w/o/w) and lipid film hydration methods, respectively. After three subcutaneous immunization of BALB/c mice with various formulations, ELISA technique was used to measure interferon‐γ (IFN‐γ) and interleukin‐4 (IL‐4) cytokines levels in splenocytes as well as serum anti‐HspX/EsxS IgG1 and IgG2a titers. The results of the current study showed that PLGA/HspX/EsxS/DOTAP formulation was able to induce higher levels of FN‐γ, IgG1, and IgG2a responses compared with BCG as the positive control, HspX/EsxS, HspX/EsxS/DOTAP and PLGA/HspX/EsxS formulations. Our results suggest that PLGA NPs, as delivery system, and DOTAP, as adjuvant, have a good potential to enhance immune responses against HspX/EsxS antigen after subcutaneous immunization of BALB/c mice.