Abstract: A truncated gene encoding the A/D antigenic domains (549 bp) of E2 in classical swine fever virus (CSFV) was amplified by RT-PCR from the genomic RNA of CSFV C strain, cloned into pET-32a expression vector to obtain recombinant pET-32a-CSFV-E2, and then sequenced.The result was the right interested gene.The recombinant plasmid was transformed into BL21 and induced with isopropyl-β-D-thiogalactopyranoside (IPTG).After expression,we could see our target band about 39 ku with SDS-PAGE.To purify the His-trap protein in different conditions,and we could get the best one with the most productive target protein.Western blotting indicated that the expressed antigen protein could be recognized by the positive sera of CSFV (the sera from our homemade anti-rabbit one and the clinical swine one).It would benefit the creation of ELISA kit and research on the antibody levels of pigs.

Key words: classical swine fever virus （CSFV） C strain; A/D antigen domains; truncated expression