Cloning of diagnostic 31/32 kilodalton antigens of Schistosoma mansoni.

A cDNA library derived from messenger RNA of adult Schistosoma mansoni was constructed in lambda gt11 and schistosome antigens were expressed as fusions with the amino terminus of the beta-galactosidase of Escherichia coli. Using mouse and human infection sera, recombinant clones specific for a 31/32 kDa doublet having a potential in the immunodiagnosis of schistosomiasis were selected. The specificity of the clones was verified by their reactivity with monoclonal antibodies. The identity of the cloned epitopes with those of the native proteins was confirmed by Western blot analysis of total schistosome proteins, using both antibodies affinity purified from the fusion proteins and antisera raised in rabbits against the fusions. The reactivity of the cloned antigens with human infection sera suggests their usefulness for the immunodiagnosis of human schistosomiasis.