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

Research paper by F F Salah, A A El Bassiouny, I I Rabia, Z Z Demerdash, M M Roshdy, Z Z Shaker

Indexed on: 25 Apr '06Published on: 25 Apr '06Published in: Parasitology Research



Abstract

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<0.01) was detected between the number of S. haematobium eggs excreted in 10 ml urine and the CSA level detected in the sera of S. haematobium-infected patients. Our data show that the use of anti-S. haematobium MAbs for the detection of CSA provides a sensitive and specific method for the immunodiagnosis of active S. haematobium-infected patients. Moreover, CSA assay using this anti-S. haematobium MAb/ELISA system was proven to correlate with intensity of infection and hence morbidity assessment.