Exploitation of two selected immunogenic proteins, OmpA and BauA, for protection against Acinetobacter baumannii infection
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motahare tamehri,1 iraj rasooli,2,*
1. Shahed University
2. Shahed University
- Introduction: Acinetobacter baumannii is a hospital opportunistic pathogen, which is a gram-negative and non-flagellated bacillus, which is considered as a common nosocomial infection with high mortality that mostly causes sepsis and meningitis. And infection of the urinary tract. Reproduction and persistence of A. baumannii in eukaryotes based on iron uptake functions including siderophore biosynthesis. Iron transfer into the cytosol is mediated by specific membrane receptors that detect iron-siderophore complexes. The expression of this Acinetobactin-mediated iron uptake system is critical for the intracellular growth of A. baumannii. OmpA is the most abundant membrane protein gram-negative bacteria and is also the major protein of bacterial pathogenesis. The production of new monoclonal antibodies against outer membrane protein A (OmpA) could be considered as a potential tool to improve the treatment of A. baumannii infections. The A. baumannii is usually resistant to beta-lactams, aminoglycosides, rifampin, and fluoroquinolones. This bacterium has led to the use of new therapies such as vaccines. No vaccine is known for this bacterium, but it is still worth considering. In this study, we used two separately selected and recombinant proteins, OmpA and BauA, as vaccine candidates to evaluate immunogenicity against A. baumannii in a mouse model.
- Methods: Based on a pre-designed primer from Shahed University Bank, BauA and OmpA gene fragments were extracted from the bacterial genome PCR and the clones simulated in pet28 were expressed in Escherichia coli BL21 (DE3). The product was analyzed by SDS-PAGE method and purified by the Ni_NTA affinity chromatography method. These proteins were injected into BALB/c mice separately and in combination. The titer of IgG-specific antibody produced against each group was determined after experiment using the indirect ELISA method. Bacterial proteins were then identified by IgG immunoblotting.
- Results: OmpA and BauA were already reported to raise antibodies against these proteins. The same results were obtained. The combination of the two antigens led to significant protection against A. baumannii in comparison to the single antigens.
- Conclusion: Administration of the combined antigens triggers better protection than single antigens.
- Keywords: Acinetobacter baumannii, Antigen, Antibody, Vaccine, OmpA, BauA.
