Cloning and expression of Toxoplasma gondii dense granule antigen 2 (GRA2) gene by Pichia pastoris

Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
The Southeast Asian journal of tropical medicine and public health (Impact Factor: 0.72). 10/2012; 43(1).


Detection of Toxoplasma gondii infection is essential in pregnant women and immunosuppressed patients. Numerous studies have shown that the recombi-nant production of several Toxoplasma antigens, including dense granule antigens (GRAs) has high potential as diagnostic reagents. In the present study, we pro-duced GRA2 using Pichia pastoris system. RNA of T. gondii RH strain tachyzoite was used as a template to produce cDNA clones of full-length GRA2 via reverse transcriptase PCR. Amplicons were inserted into pPICZa A and the recombinant plasmid transformed into P. pastoris, X-33 strain. The expressed recombinant pro-tein was identified by SDS-PAGE and Western blotting. A recombinant protein of ~28 kDa was produced, which could be detected by toxoplasmosis positive human sera indicating that the recombinant protein retained its antigenicity. The present study indicates that P. pastoris-expressed GRA2 should be useful for detection of Toxoplasma infection.

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