Abstract:

Objective  To clone and express autophagy-related protein 3 （TgAtg3） gene of Toxoplasma gondii, and obtain the specific polyclonal antibody against TgAtg3.  Methods  TgAtg3 cDNA was inserted into prokaryotic expression vector pET28a. After identification, the constructed plasmid pET28a-TgAtg3 was transformed into E. coli Rosetta cells, and induced by special induction medium for expression of the protein. The recombinant protein was purified via Ni-NTA affinity chromatography. Western blotting assay was performed with anti-His tag mouse monoclonal antibody as the primary antibody. Rabbits were immunized with 125 μg purified TgAtg recombinant protein. Each rabbit received 4 immunizations at 2-week intervals with the same dose of antigen. The specific anti-TgAtg3 polyclonal antibody was obtained, and analyzed by Western blotting and indirect immunofluorescence assay （IFA）.  Results  pET28a-TgAtg3 plasmid was identified by restriction enzyme digestion, PCR amplification and sequencing. SDS-PAGE and Western blotting analysis showed that the recombinant TgAtg3 protein （about M_r 44 000） was expressed in E. coli Rosetta cells. TgAtg3 protein from tachyzoite lysates was recognized by the specific anti-TgAtg3 polyclonal antibody. IFA assay determined that the specific polyclonal antibody bound to TgAtg3 protein from the cytoplasm of tachyzoites.  Conclusion  The obtained soluble polyclonal antibody against TgAtg3 can specifically react to the endogenous TgAtg3 protein.

Key words: Toxoplasma gondii, Autophagy-related protein 3, Clone, Expression, Polyclonal antibody