Immunogenicity of the combination of two outer membraneproteins, Oma ۸۷ and BauA against Acinetobacter baumannii infectionin a murine model

Background and Aim : Acinetobacter baumannii is a mortal nosocomial pathogen. Outermembrane proteins (OMPs) of gram-negative bacteria are known as powerful strongimmunogens.BauA is the corresponding siderophore receptor of A. baumannii. In addition toantibacterial and opsonizing activity, monoclonal antibodies produced against IROMP can alsoblock the in vitro iron absorption system. Oma۸۷ has been stated introduced as an immunogenicouter membrane protein per via contrary reverse vaccinology. In this study, After purification, theywere injected in combination to create immunity in mice. After that, the level of IgG in them wasevaluated by ELISA method and the established safety was evaluated. As a result, theadministration of combination antigens provides better protection than individual antigens.Methods : In this study, both Oma۸۷ and BauA proteins were cloned into the plasmid pET۲۸a.After purification of proteins, dialysis was performed by dialysis membrane. they were injected incombination to create immunity in mice. Blood samples were taken from mice at least once every۱۵ days and combined injections were performed. After that, the level of IgG in them wasevaluated by ELISA method and the established safety was evaluated.Results : The combination of the two antigens led to significant protection against A.baumanniiin comparison to the single antigens. As a result, the administration of combination antigensprovides better protection than individual antigens. The ELISA results showed maximum antibodytiter after the third booster injection in mice. Difference in antibody titer between first and seconddoses of immunization was statistically significant. The rise in antibody titer after thirdimmunization was also significant while there was no statistically significant rise after third dose.Conclusion : Protective effect of A. baumannii receptor protein (BauA), a cross-antigen that is akey protein in the iron uptake process and its combination with Oma۸۷, a protein that foldsmembrane proteins, against bacterial infection in the animal model evaluated And showed betterimmunity than previous single protein vaccines. Productionof vaccines that could effectivelyprevent bacterial colonization could significantly aid diagnostic and therapeutic aspects ofnosocomial infections caused by this bacterium.