Human schistosomiasis haematobium : effective diagnosis of active infection using a pair of monoclonal antibodies against soluble egg antigen

The present study was designed to prepare monoclonal antibodies (MAbs) against Schistosoma haematobium soluble egg antigen (SEA) with immunodiagnostic potential for urinary schistosomiasis. From a panel of MAbs, a pair of IgG1 MAbs (2D/11C and 10B/2C) specific for S. haematobium SEA was selected. Both MAbs recognized one band with a 42-kDa molecular weight by western blots. The pair of MAbs was employed in sandwich ELISA for the detection of circulating schistosome antigen (CSA), one as antigen-capturing antibody and the other as peroxidase-conjugated antigen-detecting antibody. The lower detection limit of the assay was 1 ng/ml of S. haematobium SEA. The assay was performed on sera of 65 S. haematobium-infected patients, 25 patients infected with other parasites (Fasciola hepatica, Echinococcus granulosus), and 20 noninfected individuals. CSA was demonstrated in 89% of the S. haematobium-infected group. However, CSA was negative in the sera of healthy individuals and patients infected with other parasites, giving an overall specificity of 100% for the CSA assay. A positive correlation (r=0.37, p