Abstract: AIM:To isolate Sj2 2 .6 gene and construct an expressive clone of r Sj2 2 .6 .METHODS: A S.japonicum adult c DNA library was screened by use of immune rabbit serum. From the possitive clones,one(λSj5 1 4,encoding Sj2 2 .6 ) was amplified by PCR to obtain its c DNA in- serts that was subcloned into the expressive plasmid vector p GEX- 1λtat Eco RI cloning site. The recombinants were induced by IPTG to express target protein which was analysed by SDS- PAGE and Western blotting. RESULTS:The specific product of PCR was about 930 bp which was subcloned in to pGEX-1λt. Two positive expressive clones were obtained, pGSj6 and pGSj24, which expressed specific protein with a molecular weigh t of 22.6 kDa. Th is recombinant protein ( rSj22.6) could be specifically recognized by immune rabbit serum. But the expressed product was not fusion protein, which meant that rSj22.6 was separated from the SjGST that is encoded by the plasmid pGEX-1λt. CONCLUSION: Sj22.6 antigen gene was screened from Sj adult cDNA library and subcloned in to pGEX-1λt, which resulted in two expressive clones, pGSj6 and pGSj24 that expressed rSj22.6.

Key words: Schistosoma japonicum, Sj22.6 kDa, gene cloning, inducible expression, recombinant antigen