From a panel of mouse monoclonal antibodies reactive with a repeating epitope of the schistosome circulating anodic antigen, an IgG1 monoclonal antibody was selected. This monoclonal antibody was applied in a sandwich enzyme-linked immunosorbent assay as capture antibody and as alkaline phosphatase labeled conjugate.
This assay allowed a sensitive quantitation of circulating anodic antigen in serum samples of infected individuals, detecting < 1 ng antigen/ml serum.
In Schistosoma mansoni infected individuals from Zaire, the level of antigen in serum correlated with fecal egg output. The lower detection level of the immunoassay corresponded to a level of about 10 eggs/gm feces.