Brucellosis is an important zoonotic disease of economic significance. Brucella species are gram-negative, facultative intracellular bacteria, and are capable of replicating in the phagosomes of macrophages. They cause infection in several animal species and humans. Prevention of the disease is necessary for eradication of human and cattle infection. Characterization and evaluation of different antigens of Brucella cells has a key role in progression of prevention programs. Here, we report the production and purification of recombinant 31kDa cell surface protein Brucella melitensis (BCSP31).

In Tarbiat Modares University Laboratory, Brucella 31kDa cell surface protein gene was amplified with PrimeSTAR® HS DNA polymerase, cloned in pJET1.2. The target gene was subcloned in pET28a (+). Recombinant pET28a vectors were transformed into E coli BL21 (DE3). Expression of recombinant protein was induced with 1mM IPTG and recombinant protein was purified by Ni-NTA agarose resins. Recombinant proteins were eluted with 250mM imidazol. Imidazol removed by dialysis. Proteins were assayed by Western-blotting and rBCSP31 was probed by Brucella rabbit anti serum. Purified protein conjugated to detoxify LPS of Brucella. This complex injected to BALB/c mice. Percentage of clearance and log unit protection in injected mice showed the significant protection against colonization of Brucella melitensis in spleen of mice. BCSP31 were successfully cloned, expressed and purified. The recombinant proteins were conjugated to detoxify LPS. Injections of this component can protection of mice against colonization in spleen of challenge strain.