High Level Expression of Recombinant Ribosomal Protein (L7/L12) from Brucella abortus and Its Reaxtion with Infected Human Sera

Brucellosis, caused by Brucella spp., is an important zoonotic disease that causes abortion and infertility in cattle and undulant fever in humans. Various studies have examined cell-free native and recombinant proteins as candidate protective antigens in animal models. Among Brucella immunogenes, antigen based on ribosomal preparation has been widely investigated. In this study, the immunogenic ribosomal protein L7/L12 gene from Brucella abortus, S19, was amplified by PCR and sub-cloned to prokaryotic expression vector pET28a. Escherichia coli BL21 (DE3) pLysS was transformed with pET28a-L7/L12 and gene expression was induced by IPTG. The expressed protein was purified by affinity chromatography with Ni-NTA resin. The concentration of purified recombinant protein calculated to 8 mg/L of initial culture. The integrity of product was confirmed by Western-blot analysis using a standard rabbit anti Brucella abortus ribosomal protein L7/L12 antibody. Sera reactivity of five infected individual were further analyzed against the recombinant ribosomal L7/L12 protein. Data indicated that recombinant ribosomal L7/L12 protein from Brucella abortus was recognized by patient sera.