Immuno-enzymatic assay for the detection of Schistosoma mansoni antigens in serum of mice harbouring bisexual or unisexual light worm infections.

Enzyme-linked immunosorbent assay (ELISA) double antibody technique was standardized for detecting S. mansoni polysaccharide and protein antigens in serum of infected mice. Anti-sera specific for either worm components were obtained in sheep and peroxidase conjugates prepared from each serum. The immunoenzimatic test for protein could detect as little as 6 micrograms/ml antigens, and the test for polysaccharides 3 micrograms/ml. Both bisexual and unisexual male worm low infections were produced, and studied for as long as 27 weeks post-exposure. Worm components were found in serum from both types of infections and in progressively higher percentages of animals until the end of the 27 weeks observation period. For unisexual male infections this percentage reached from about 50% to 60% of mice, and 100% for bisexual infections. Significantly higher antigen concentrations in serum were found at 27 weeks for bisexual infections, no antigen increase being detected in relation to starting egg secretion, which occurred at 5 week infections.