Cloning, expression and serological evaluation of H3 protein from Echinococcus granulosus

Abstract

To clone and express the basement membrane specific heparan sulfate proteoglycan core protein (H3), and to evaluate its effect in detection of human cystic echinococcosis (CE). The H3 gene immunoscreened from the cDNA library was cloned into pGEX-4T vector. The recombinant plasmid pGEX-3X-AgB8/3 was transformed into Escherichia coli BL21 strains and induced by isopropyl-β-D-thiogalactopyranoside (IPTG). Then the expressed recombinant protein was purified by affinity chromatography and its effect in the detection of CE was evaluated by ELISA. Meanwhile, the effects of H3 and two antigens that the research group prepared before (purified HCF and rAgB8/2) in CE detection were compared. The plasmid pGEX-4T-H3 was successfully constructed and H3 was successfully expressed in prokaryotic cells. The sensitivities of the recombinant H3, purified HCF and rAgB8/2 in CE detection were 84.0% (68/81), 90.1% (73/81) and 77.8% (63/81) respectively, and there was no statistical difference among them (χ2 = 4.58, P > 0.05). The cross reactions of recombinant H3 with the sera of the patients with CE, cysticercosis and schistosomiasis were 63.3% (19/30), 16.7% (5/30) and 5.0% (1/20) respectively, and the cross reaction was 0 with the sera of healthy people. The specificities of recombinant H3, purified HCF, and rAgB8/2 were 80.8% (105/130), 71.5% (93/130) and 82.3% (107/130) respectively, and there were no statistical difference among them (χ2 = 5.71, P > 0.05). The recombinant H3 is a potential diagnostic antigen for CE detecting.