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Page No. : 111-115

ABSTRACT

Toxoplasma gondii is an obligate intracellular protozoan parasite infecting all warm-blooded animals including human and birds. The present study was carried out to express an 18 kDa bradyzoite specific surface protein (SAG4) of Chennai isolate of T. gondii. A 519 bp sequence coding for SAG4 was PCR amplified from the genomic DNA and cloned into a PGEMT cloning vector to facilitate sequencing and characterization. Nucleotide sequence analysis revealed 519 nucleotides encoding a 172 amino acid polypeptide. Subsequently, the entire gene was sub-cloned into prokaryotic expression vector pET32aand expressed with thioredoxin as a fusion protein. The IPTG induction of recombinant clones resulted in the expression of SAG4 protein as analyzed by SDS-PAGE and confirmed by western blotting and about40kDa protein was observed in SDS-PAGE and western blotting.

Keywords: Cloning vector, recombinant antigen, surface antigen, Toxoplasma gondii