Detection and Characterization of Schistosoma japonicum-Derived Antigens by Inhibition Enzyme-Linked Immunosorbent assay (IELISA)

Abstract

An inhibition enzyme-linked immunosorbent assay (IELISA) was used to detect schistosome antigens. Preparations were obtained from eggs, female adult worms and male adult worms of Schistosoma japonicum. Using appropriate titers of S. japonicum infected mouse serum (IMS), it was possible to detect less than 0.05μg/ml of soluble egg antigens (SEA) added to phosphate-buffered saline. The sensitivity of IELISA was dependent upon the concentration of IMS used, as well as upon the source of antigens. The IELISA utilizing IMS was not suitable for the detection of male worm antigens. Specificity studies showed that no cross-reactivity was observed between SEA and worm antigens. SEA preparations crossreacted with egg glycoprotein fractions more than with egg protein fractions. The IELISA utilizing IMS can quantitate the degree of antigenic cross-reactivity, and can determine the distribution of antigens by using appropriate blocking antigens.