Immunogenicity of recombinant adenovirus co-expressing the l7/l12 and bcsp31 proteins of brucella abortus

Brucella poses a great threat to animal and human health, and vaccination is a good way of controlling the bacterium. In this study, the immune response and protection ability of a recombinant adenovirus Ad-LL/BP containing L7/L12 and BCSP31 proteins of Brucella abortus (B. abortus) were evaluated in BALB/c mice model. Firstly, Adenovirus vector Ad-CMV and the recombinant adenovirus Ad-LL/BP were amplified in HEK 293AD cells. The TCID50 values of Ad-LL/BP and Ad-CMV were 10−8.68/0.1 mL and 10−8.35/0.1 mL, respectively. Mice were inoculated with 100 TCID50/mouse of Ad-LL/BP or Ad-CMV. Vaccination of mice with Ad-LL/BP vaccine was able to elicit higher IgG, IgG1 and IgG2a antibody levels when compared with Ad-CMV and PBS control animals (P0.05). Ad-LL/BP vaccine was able to reduce significantly the numbers of B. abortus in the spleens from the immunized mice. These results indicated that the recombinant Ad-LL/BP vaccine induced mainly cell-mediated immunity and partly humoral immunity, and provided moderately protection against B. abortus infection. Therefore, the vaccine could be further developed into a live-vector vaccine against B. abortus.