Brucella spp. causes zoonotic infections. Lipopolysaccharide (LPS) is a major antigenic Brucella structure stimulating a T-independent response. For eliciting cell-mediated immunity against LPS, it should be conjugated with a polypeptide antigen. The aim of this study was to evaluate the immunogenicity of Brucella abortus 55-kDa recombinant surface protein (BC55) conjugated with detoxified LPS in black and albino type C (BALB/c) mouse model.Materials and methods:
The B. abortus bc55 gene was amplified and cloned into pET32a (+) plasmid. The recombinant vectors were transferred into Escherichia coli GM2163 and the expression of the recombinant protein was induced by 1-mmol/l isopropyl β-D-1-thiogalactopyranoside. The BC55 protein was purified using a nickel resin column and, next, conjugated with detoxified LPS and injected subcutaneously to BALB/c mice including five groups. B. abortus 544 and PBS were used as positive and negative controls, respectively. Recovered bacteria from spleen of mice were compared with those of members of the control group.Results:
The BC55 with 57-kDa size was purified by resin–nickel column method. The conjugation of BC55 + dLPS induced major immune response, significantly higher than each of the dLPS, PBS, and BC55 protein components.Conclusion:
The conjugation of BC55 + dLPS induced responses significantly higher than each of the dLPS, PBS, and BC55 protein components. In addition, the dLPS + BC55 conjugate not only had efficient results in the induction of immune responses as a new vaccination strategy, it (also) can reduce the number of B. abortus in spleen.