Recombinant rabies virus expressing chimeric Omp31/sodC or AHCY gene from Brucella melitensis elicits high level of antibodies and secretary cytokines in mice

Background: The rabies virus (RV) vector LBNSE expressing foreign antigens has shown considerable promise as vaccines against viral and bacteria diseases, which is effective and safe. We produced a new RV-based vaccine vehicle expressing Brucella melitensis Omp31/sodC or AHCY gene by reverse genetics technology. The aim of this study was to investigate the cellular and humoral immunity of recombinant viruses. Results: The recombinant virus rLBNSE-SOD and rLBNSE-AHC retained growth properties similar to those of vector rLBNSE both in BSR and mNA cell culture. The Omp31/SODC and AHCY gene was expressed and detected by immunostaining. To compare the immunogenicity of LBNSE-SOD and LBNSE-AHC, mice were immunized with each of recombinant virus by intramuscular (i.m.). Then mice were bled at days 7, 14 after the immunization for the measurement of cytokines and virus neutralizing antibody (VNAs). The parent virus (LBNSE) without expression of any foreign molecules was included for comparison. It was found that mice inoculated with LBNSE-SOD and LBNSE-AHC showed no any signs of disease and exhibited seroconversion against RV. Our findings showed that mice were immunized with each of these recombinant RVs by intramuscular (i.m.) developed efficacy cellular and humoral immunity. The mRNA level of cytokines (IFN-γ and IL-2; IL-4 and IL-10) and VNA level against rabies virus in the blood of mice were increasing after immunization with recombinant RVs. There were no obvious histopathological changes in the brain samples of all mice. Conclusions: The studies suggested that recombinant RVs expressing Omp31/SodC or AHCY gene would elicit high level of antibodies and secretary cytokines and provided a promising vaccine candidate in mice.