Abstract: Use the genome DNA of pseudorabies (PRV) virus SD strain as template,the major epitope of PRV envelop glycoprotein gD was amplified by polymerase chain reaction (PCR)and cloned into pGEM-T vector,then inserted into the downstream of T7 promoter to construct an expression plasmid pET-32a. After induction by IPTG,the fusion protein was highly expressed in Escherichia coli BL21(DE3) in the form of inclusion bodies. The recombinant protein was purified with His-bind affinity chromatography. SDS-PAGE and Western blotting analyses revealed that the recombinant protein with the expected 45.2 ku could react with pig serum containing antibody against PRV. All results indicated that the recombinant fusion protein can be used as an antigen of diagnostic assay to detect the PRV antibody in pig serum.

Key words: pseudorabies virus; envelope glycoprotein gD; major epitope domain; prokaryotic expression