In order to clone the formyltransferase gene (Wbkc) of Brucella abortus,express the gene in E.coli and detect the immunogenicity of the expressed protein,the Wbkc gene was amplified from the genomic DNA of Brucella abortus by PCR.The amplified fragments were digested with BamHⅠ and SalⅠ and then cloned into the pET28a vector.The constructed recombinant plasmid pET28a-Wbkc was transformed to E.coli BL-21 and induced to express the fusion protein.The protein was then purified by histidine-binding resin column chromatography and the immunogenicity was detected by Western blot.The recombinant plasmid was verified by PCR,double-enzyme cleavage and sequencing analysis.A specific protein band of 29 000 (relative molecular mass) was identified by SDS-PAGE and the expressed product showed good immunoreactivity by Western blot.