Fusion expression and targeting ability of the single-chain Fv antibody against the anti-fecundity immunity molecule,soluble immature egg antigen SIEA26-28kDa from Schistosoma japonica

To observe the binding sites of the single-chain Fv antibody(scFv) against the anti-fecundity immunity molecule,soluble immature egg antigen SIEA26-28kDa with different stages of Schistosoma japonica in vitro,in order to clarify its application value on the study of anti-schistsomiasis vaccines,enhanced green fluorescence protein(EGFP) coding gene was amplified and cloned to plasmid pET32a/SIEA26-28kDa-scFv and then transformed to the competent E.coli BL21(DE3) to induce the expression of scFv fusion protein.The specific antigen-binding activity of the scFv fusion protein against SIEA26-28kDa was analyzed and its targeting ability was determined by the observation of the GFP signals when the scFv fusion protein was incubated with the tissue sections of adult worms and eggs and examined under fluorescent microscopy.Under these ways,the recombinant plasmid pET32a/EGFP-scFv was successfully constructed,and the Trx-EGFP-scFv fusion protein was corrected expressed.This fusion protein could react specifically with SIEA26-28kDa molecule.The GFP signals were mainly enriched in the embryo of immature eggs,ovaries,vitellarium and the lining membrane tissue of the gut lumen of the female worms.From these observation,it is evident that the specific SIEA26-28kDa scFv has good targeting ability with embryo of immature eggs and the genital system of adult worms,thus paving a way for the targeting interference of S.japonica by using the specific SIEA26-28kDa scFv directly.