Abstract: Objective  To clone and express the rhoptry protein 17 （ROP17） gene of RH strain of Toxoplasma gondii，analyze the antigenicity of recombinant protein.  Methods   Total RNA was extracted from tachyzoites of RH strain of T. gondii. The open reading frame of TgROP17 gene was amplified with a pair of specific primers which was designed according to the coding sequence of TgROP17 gene （GenBank accession No. AM075203.1），the product of RT-PCR was digested with double restriction enzyme and ligated into a pGEX-6P-1 vector. The recombinant pGEX-6P-1-TgROP17 plasmid was transferred into E. coli DH5α and the positive clones were selected through the colony-PCR and confirmed by the double restriction enzyme digestion and sequencing. The constructed pGEX-6P-1-TgROP17 was transformed into E. coli Rosetta （DE3） and induced with IPTG for expression. The expression products were analyzed through SDS-PAGE followed by Coomassie blue staining. Western blotting assay with GST primary antibody and rabbit anti-T. gondii serum was used to confirm the expression of GST-ROP17 and analyze its antigenic properties.   Results   The product of RT-PCR was with 1 850 bp.  The recombinant plasmid pGEX-6P-1-TgROP17 was confirmed by colony-PCR，double restriction enzyme digestion and sequencing. A soluble recombinant protein with relative molecular weight of 96 000 was analyzed by SDS-PAGE followed by Coomassie blue staining. The GST tag in GST-ROP17 and the antigenicity of ROP17 were detected efficiently by Western blotting with the GST primary antibody and with the prepared antiserum against T. gondii, respectively.   Conclusion   The recombinant GST-ROP17 protein has been produced in E. coli and shows specific antigenicity.

Key words: Toxoplasma gondii, Rhoptry protein 17, Prokaryotic expression, Antigenicity