Immune modulatory and protective effects of Brucella abortus cellular antigens, arginase and elongation factor Ts, as subunit vaccines against murine brucellosis

We investigated the effects of two Brucella proteins expressed in a pMAL expression system, RocF and EF-Ts, as subunit vaccines on immune modulation and protective efficacy using a mouse model. Mice vaccinated with MBP-RocF and MBP-EF-Ts displayed increased production of TNF, IFN-r, MCP-1, IL-10 and IL-6, and TNF and MCP-1, respectively. Furthermore, mice vaccinated with MBP-EF-Ts showed decreased induction of IFN-r and Th2-related cytokines, IL-10 and IL-6. Higher proportions of CD4+ and CD8+ T cells were observed in the blood of mice vaccinated with MBP-RocF than in the PBS-vaccinated group, although the increases were not significant. Furthermore, significantly reduced Brucella proliferation in the spleens of the MBP-RocF and MBP-EF-Ts groups were observed, but inflammation of these organs was not attenuated. Overall, these results indicate that RocF and EF-Ts could be potential subunit vaccine candidates against animal brucellosis.