Protective efficacy of the recombinant lysozyme-PMAP36 fusion protein-inactivated Salmonella Typhimurium vaccine candidate via oral immunization in a murine model.

The aim of this study was to evaluate protective efficacy of S. Typhimurium ghost vaccine candidate lysed by the recombinant lysozyme-PMAP36 fusion protein via oral immunization in a murine model. Sixty BALB/c mice were equally divided into 4 groups. Group A mice were inoculated with 20 μL of sterile phosphate-buffered saline (PBS). Groups B-D mice were immunized with approximately 1 × 107, 1 × 108, and 1 × 109 cells of the vaccine candidate, respectively, in 20 μL of PBS. Salmonella-outermembrane-proteins-specific serum IgG was considerably higher in groups B-D than in group A. The interleukin-10 and interferon-γ levels in groups B-D were significantly higher than in group A. Following challenge with wild-type S. Typhimurium, all immunized groups showed a significant level of protection compared with group A. The highest protection was shown in group D. Overall, these results show that oral immunization with the candidate vaccine can effectively protect mice from S. Typhimurium infection.