Abstract：The full length of 3AB gene of foot-and-mouth disease virus (FMDV) was amplified and subcloned into pET-30a vector by two unique restriction sites. The recombinant plasmid pET-3AB was transformed into a BL21 (DE3) strain of E.coli. The recombinants were induced with IPTG at 37℃and 28℃ for expression of target protein. The product was analyzed by SDS-PAGE. The results showed that the expressed protein was solubly expressed when induced at 28℃ and formed inclusion body when induced at 37℃. Both products could reacted well with sera derived from FMDV infected cattle by western blotting. The expressed product was further purified and used as the antigen in an indirect ELISA assay for detection of different animal sera. The result showed that the partially purified 3AB protein could only react with sera derived from FMDV infected animals. This preliminary result indicated that the expressed 3AB could be used as antigen in ELISA for discrimination FMDV naturally infected animals from vaccinated animals.
