Abstract: AIM: To identify and clone structural genes encoding ES antigen from T.spiralis for preparing gene recombinant antigen of T.spiralis. METHOD: RT PCR technique was used to gain the target genes. After sequencing and restriction enzyme digestion, the genes were respectively cloned into the fusion expression vectors pEX31C, pEX31B and another expression vector pBV220 by using recombinant DNA techniques. Their expression level in E.coli was evaluated and the specificity of the expression products was also identified. RESULTS: Two structural genes encoding the specific proteins in ES antigen were obtained (0.7 kb and 0.95 kb). Compared with those reported previously, the sequences exhibited some differences. Three recombinant plasmids were constructed. It was shown that the corresponding recombinant proteins were expressed in E.coli containing the plasmids by SDS-PAGE electrophoresis. All the recombinant proteins could be recognized by sera from swine infected with T.spiralis, but the specificity of non-fusion protein was stronger than that of fusion protein. The expression level of the fusion protein was higher than that of the non-fusion protein, and the molecular weight of the expression proteins was in negative correlation with the expression level under the same condition. CONCLUSION: Three recombinant proteins expressed in E.coli are candidate antigenic proteins for preparing gene recombinant antigen of T.spiralis.

Key words: Trichinella spiralis, gene, sequencing, recombinant plasmid, expression