Vaccination of 50S ribosomal protein L27 decreased susceptibility to Brucella abortus 544 infection in BALB/c mice

Abstract

BALB/c mice were vaccinated with Brucella (B.) abortus recombinant protein L27 (50S ribosomal protein L27) cloned into a pMal vector system. L27 was induced, purified and injected intraperitoneally (IP). Mice were vaccinated on 0-, 15- and 35-day. Serum cytokines were evaluated on 36- and 49-day from first vaccination. Mice were intraperitoneally infected with 5×104 CFU of virulent B. abortus 544 on day-50 and sacrificed after two weeks from infection. Bacterial burden from the spleen was quantified and showed a 0.7- and 0.9-log reduction in vaccinated mice in comparison to PBS and MBP (maltose binding protein) groups respectively. Cytokines in the serum demonstrated increased interferon-gamma (IFN-γ) and other pro-inflammatory cytokines such as macrophage chemoattractant protein-1 (MCP-1) and interleukin 6 (IL-6). On the other hand, interleukin 10 (IL-10) was attenuated in the sera of vaccinated mice. This cytokine profile is indicative of a cell-mediated type of immune response which is favorable for the eradication of intracellular infections. The current study showed the potential of another B. abortus ribosomal protein in inducing protective immunity against B. abortus infection.