[Screening and identification of phage antibodies from phage display library against Schistosoma japonicum].

Objective: To obtain single chain variable fragment(ScFv) against the circulating antigen(CAg) from Schistosoma japonicum(Sj).
Methods: Metabolic antigen of adult worm of Sj (Sj-MAg) was used in the panning of phage library against Schistosoma japonicum. The activity of Sj-MAg-binding phage clones was assayed by ELISA. The specificity of expression products of the positive clones was analyzed by ELISA, SDS-PAGE and Western blotting.
Results: Seventy-two randomly selected clones were tested for the presence of anti-Sj-MAg ScFvs, 6 clones showed positive. The specificity of these 6 clones was confirmed by binding them to antigens of other four trematodes. Two clones (B04, C24) were found to bind to Sj-MAg but not to any of the antigens of other four trematodes and their expression products were about 31 kDa in size.
Conclusion: ScFv antibodies against the circulating antigens from Schistosoma japonicum Sj-MAg can be selected and manufactured from the antibody library.