Protective Efficacy of the OprF/OprI/PcrV Recombinant Chimeric Protein Against Pseudomonas aeruginosa in the Burned BALB/c Mouse Model

BACKGROUND: Pseudomonas aeruginosa infection is the major cause of death in burn patients. Thus, in this study, a chimeric vaccine harboring the OprF(185–350)–OprI(22–83)–PcrV was designed and expressed in Escherichia coli. The immunogenicity of the recombinant chimer, OprI, OprF, and PcrV was studied in a burned mouse model. METHODOLOGY: Recombinant proteins including the proposed chimer, OprF, OprI, and PcrV were expressed in the E.coli. Mice were immunized with the purified recombinant proteins, and the antibody titre was estimated in the sera obtained from immunized mice. Immunized and control mice were challenged with 2, 5, and 10xLD(50) of the P. aeruginosa strains (PAO1, PAK, and R(5)), and microbial counts were measured in the skin, liver, spleen, and kidney of the studied mice. RESULTS: Results showed that the antibody titre (total IgG) was significantly increased by injection of 10 μg of chimeric protein in the experimental groups compared to the control groups. The antibody survival titre was high until 235 days after administration of the second booster. The survival rate of the mice infected with 10xLD(50) was significantly increased and the number of bacteria was reduced, especially in the internal organs (kidney, spleen, and liver) compared to the mice immunized with any of the OprF, OprI, and PcrV proteins alone. CONCLUSION: The findings of our study revealed that the chimeric protein is a promising vaccine candidate for control of the P. aeruginosa infection.