Abstract: In order to analyze the immunogenicity of Toxoplasma gondii embryogenesis-related protein （TgERP）, the TgERP gene was amplified from genomic DNA of T.gondii RH strain by PCR and then cloned into prokaryotic expression plasmid pET-30a (+). The recombinant plasmid pET-30-ERP was transformed into Escherichia coli BL21 (DE3) and induced by IPTG. The expressed product was purified by Ni-NTA His Bind Resin affinity chromatography and analyzed by Western blotting. The polyclonal antibody against the recombinant protein was prepared by immunizing New Zealand White rabbits with the purified protein. PCR amplification and restriction analysis proved that the restriction prokaryotic expression plasmid pET-30a (+) was constructed correctly and sequencing results showed that the cloned TgERP gene was identified to be the corresponding sequence reported on the website （http: //toxodb.org）. The TgERP protein was expressed under 1.0 mmol/L IPTG at 37 ℃, shaking for 6 h. SDS-PAGE analysis showed the protein product was successfully purified with a molecular weight of about 16.7 ku. Western blotting and ELISA analyses indicated that the TgERP protein reacted with sera from vaccinated rabbit. In conclusion, it could be a potential candidate antigen for developing new detection methods or new sub-unit vaccine against toxoplasmosis.

Key words: Toxoplasma gondii; Toxoplasma gondii embryogenesis-related protein gene; prokaryotic expression; immunogenicity