Zahra Akbari - Department of Biology, Shahed University, Tehran-Iran,
Iraj Rasooli - Molecular Microbiology Research Center and Department of Biology, Shahed University, Tehran-Iran
Anthony B. Schryvers - Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Canada

Background and Aim : The complexity of treating Acinetobacter baumannii infections due to the emergence of resistant strains has led researchers to confront this pathogen by developing vaccines. In this study, we used two important virulence factors of A. baumannii to elicit immunity against the A. baumannii. The immunogenic loops were from Baumannii acinetobactin Utilization A (BauA) and ۳۴kD outer membrane protein (Omp۳۴). Methods : A new hybrid antigen approach was used in which the superficial epitopes of the TbpA receptor protein of Neisseria meningitidis were displayed on the C-lobe derivative of the TbpB surface lipoprotein, named the loopless C-lobe (LCL). The nucleotide sequences of the immunogenic loops were amplified and cloned into the LCL. The hybrid antigens in the LCL scaffold were expressed in the E. coli cytoplasm as soluble antigens. The hybrid antigens were used to immunized mice followed by challenge experiments of murine sepsis with a clinical isolate of A.baumannii (ABI۰۲۲). Results : Mice immunized with the hybrid antigen of the BauA loop۷ in position ۳ and Omp۳۴ loop ۳ in position ۱ of LCL ( BauAL۷P۳Omp۳۴L۳P۱) brought protection against A. baumannii infection. Conclusion : The findings support the use of multiantigens to induce broadly reactive antibody responses against heterologous A. baumannii strains.

Immunogenicity., Vaccine. , BauA., Omp۳۴., Acinetobacter baumanni., Hybrid Antigen