In-Silico Analysis and Protective Efficacy of the PcrV Recombinant Vaccine against Pseudomonas Aeruginosa in the Burned and PA-Infected BALB/c Mouse Model

Background: Pseudomonas aeruginosa is considered as the most severe cause of infections in burn patients and pneumonia infections. Objective: To study the protective effects of recombinant protein vaccine harboring the PcrV of P. aeruginosa in the mice model of burn and respiratory infections. Methods: Recombinant protein vaccine harboring the PcrV was expressed in the E.coli BL-21 strain. Mice were immunized with the purified recombinant protein and the antibody titer was measured in the sera obtained from the immunized mice. Immunized and control mice were challenged by active and passive immunization. The microbial counts in the lung, skin, liver, spleen, and kidney were compared with the control mice. Results: Bioinformatics analysis indicated that the PcrV protein was conserved in 1552 clinical and environmental isolates. Also, the isoelectric point (pI), molecular weight, and Grand Average of Hydropathy (GRAVY) score were analyzed. Mice were injected with recombinant protein and serum from immunized mice reacted strongly with recombinant antigen at a dilution of 1:64000. The survival rate of the mice infected with 5 x LD50 of the PA was significantly increased up to 75% in the standard strains (PAO1 and PAK), and the number of bacteria, especially in the internal organs (kidney, spleen, and liver) significantly reduced compared to the mice immunized with the placebo. Conclusion: Our results demonstrated that the PcrV protein could be an effective candidate vaccine for generation of immunity against the P. aeruginosa infection.