Moslem Shojaei - Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
Mojtaba Tahmoorespur - Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
Mahdi Soltani - Department of Biotechnology, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman, Iran
Mohammad Hadi Sekhavati - Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran

Objective(s): Vaccination is one of the most effective means to protect humans and animals against brucellosis. Live attenuated Brucella vaccines are considered effective in animals but they may be potentially infectious to humans, so it is vital to improve the immunoprotective effects and safety of vaccines against Brucella. This study was designed to evaluate the immunogenicity of DNA vaccines encoding B. melitensis outer membrane proteins (Omp۲۵ and Omp۳۱) against B. melitensis Rev۱ in a mouse model. Materials and Methods: For this propose, Omp۲۵ and Omp۳۱ genes were cloned (individually and together) into the eukaryotic expression vector pcDNA۳.۱/Hygro (+). Expressions of recombinant plasmids were confirmed by SDS-PAGE and Western blot analysis. Six groups of BALB/c mice (seven mice per group) were intramuscularly injected with three recombinant constructs, native pcDNA۳.۱/Hygro (+) and phosphate-buffered saline (PBS) as controls and subcutaneous injection of attenuated live vaccine Rev۱.Results: Results indicated that DNA vaccine immunized BALB/c mice had a dominant immunoglobulin G response and elicited a T-cell-proliferative response and induced significant levels of interferon gamma (INF-γ) compared to the control groups.Conclusion: Collectively, these finding suggested that the pcDNA۳.۱/Hygro DNA vaccines encoding Omp۲۵ and Omp۳۱ genes and divalent plasmid were able to induce both humoral and cellular immunity, and had the potential to be a vaccine candidate for prevention of B. melitensis infections.

Brucella melitensis, DNA vaccine, Omp۲۵, Omp۳۱, Protective immunity