Pseudomonas aeruginosa induces the complications after burns, injuries, surgical interventions and appears to be one of the main causative agents of nosocomial infections. This pathogen has the high resistance to the antibacterial preparations, therefore the immunoprophylaxis is considered as one of the major approaches to reduce Pseudomonas infection. Objective: The aim of our investigation is to study the protective properties of the recombinant complex of the outer membrane protein F (OprF) and a non-toxic variant of the exotoxin A (toxoid) against Pseudomonas infection. Methods: The recombinant proteins which contained the additional histidine residues were synthesized into Escherichia coli with isopropyl-βD-thyogalactopyranoside (IPTG). The recombinant proteins were purified by affinity chromatography on Ni-Sepharose. The preparations of recombinant proteins were injected intraperitoneally into the mice. Aluminum hydroxide was used as an adjuvant. For an experimental infection in mice, animals were challenged intraperitoneally by a live virulent culture of P. aeruginosa (PA-103 strain). Results: The best protective effect for the complex containing 25 μg OprF and 50 μg toxoid was identified when we used the double immunization of mice (Index of efficiency of the protective properties in this case was 4.0). Indexes of efficiency of separated recombinant proteins which were injected twice in the same doses were 2.0 for OprF и 2.3 for toxoid. The triple immunization of animals was inefficient for separated recombinant proteins in the same doses. The injection of doses which were lowered twice (12.5 μg for OprF and 25 μg for toxoid) resulted in increased survival of mice immunized by individual proteins (indexes of efficiency: 3 for OprF and и 3,5 for toxoid). However when we administered to the complex of proteins with the same doses Index of efficiency was 2.8. Conclusion: It was shown that the maximum protective effect in a short time is achieved by the combination of double immunization and the mixture of the recombinant proteins OprF and the 25 and 50 μg doses of recombinant toxoid .
Immunotherapy with IgY Antibodies toward Outer Membrane Protein F Protects Burned Mice against Pseudomonas aeruginosa Infection
