Abstract: Alpha-toxin gene was amplified from a field strain of Clostridium perfringens by polymerase chain reaction (PCR), PCR product was cleaved with restriction endonucleases EcoR Ⅰ and Nco Ⅰ, and inserted into the EcoR Ⅰ/Nco Ⅰ site of pET\|28a(+)vector. Recombinant pET-28a-CPA plasmid was transformed into BL21 (DE3)cells. The obtained plasmids were studied in detail by PCR, restriction endonuclease analysis and nucleotide sequencing. The recombinant plasmid was transformed into E.coli BL21(DE3)and expressed under the induction of IPTG. Western blot analysis indicated that polyclonal goat-anti-serum against alpha\|toxin had specific reaction with recombinant protein. These results indicated that the target protein had a good immunogenicity．

Key words: Clostridium perfringens, alpha-toxin gene, gene cloning, nucleotide sequencing