Enzyme-linked immunosorbent assay with egg antigens of Schistosoma japonicum.

A micromethod of the enzyme-linked immunosorbent assay (ELISA) was applied to infections with Schistosoma japonicum in humans and mice with egg antigens. In mouse infections, antibody responses were detected between 6 and 8 weeks after the cercarial challenge. In human infections, a circum oval precipitin positive group showed the highest reaction values in ELISA. ELISA with egg antigens did not show any cross reaction with sera of humans infected with intestinal parasites (Ascaris, Trichuris and hookworms). Fractionation of the egg antigen was attempted using gel filtration, ion-exchange and lectin affinity chromatographies. Antigenic fractions were detected in two molecular weight groups of glycoprotein, which showed major pI value at 5-6. However, ELISA with partially purified antigen (JEA-1) did not give better sensitivity or specificity than the crude extract.