Expression of diagnostic 31/32 kilodalton proteins of Schistosoma mansoni as fusions with bacteriophage MS2 polymerase.

An expression plasmid pEx34b was used to synthesise parts of the 31/32 kDa Schistosoma mansoni antigens as fusions with the amino terminus of the phage MS2 polymerase. Purified MS2-schistosome fusion proteins reacted specifically in an enzyme-linked immunosorbent assay with sera from S. mansoni-infected patients. The observation that the majority of human sera tested recognised schistosome-specific epitopes, but not the MS2 polymerase fragment, suggests that the fusion proteins are useful for the immunodiagnosis of schistosomiasis and might be incorporated in a serological test system based on recombinant antigens.