Abstract

Brucellosis is one of the commonest zoonotic disease that is spread throughout world. In this study, we tested subcutaneous vaccines against brucellosis with formulation lipopolysaccharide (LPS) of Brucella abort us S19 strain Conjugated with the Helicobacter pylori's recombinant CagA protein and with CpG in BALB/c mouse model. BALB/c mice were immunized with different formulations three times subcutaneouse at 14-day intervals. The protective effects of two component vaccines plus CpG Adjuvant were assessed after Brucella abortus 544 challenge in different studies. The specific IgG antibodies in serum were studied by ELISA, and Antigen specific IL-4, IL-10 and IFN-gamma responses were measured in spleen of immunized mice after challenge using ELISA test. Clearance of B. abortus carried according standard protocol. B. abortus-specific IgG1 and IgG2a isotopes were measured from sera before and post challenge. In this study the IgG2a/IgG1 ratio in the mice were <1. Analysis of lymphocyte proliferation of mice showed that rCagA with concentration 1 mu g increase lymphocyte proliferation excellent compared to control group. CpG oligodeoxy nucleotides is proper to induce Th1-biased immune responses. Immunization of mice with rCagA-LPS + CpG induced a strong local and systemic Th1 immune response. Although both immunization groups LPS + CpG and rCagA-LPS + CpG had increased numbers of IFN-gamma secreting splenocytes (P<0.05). There was no significant difference in IFN-gamma production between the rCagA conjugated with LPS + CpG and others groups. Conversely, the rCagA conjugated with LPS + CpG group had a increase in more IL-4 than IFN-gamma and serum IgG1 titers higher than IgG2a (P<0.05). Naive splenocytes produced high levels of IL-10 after challenge with rCagA conjugated with LPS + CpG that indicate LPS in order prevention of inflammation by induced Th1/Th2 balance response. Vaccine current formulations enable decrease colonization and bacterial load in mice spleens after complete vaccination according immunization schedule. Vaccinations induce Th1 and Th2 immune responses. In this study, mice were protected from infection with B. abortus 544 srain showed 1-fold reduction in the number of B. abortus in the spleen compared to non immunized mice. In conclusion, vaccination with current formulation in animal model was safe and was able to induce appropriate responses and also decrease B. abortus 544 strain colonization but suggest that rCagA combined with other Components of brucella.