Characterization of monoclonal antibodies reactive with Schistosoma haematobium-soluble egg and infected human urinary antigens

Six murine monoclonal antibodies (MAbs) [Sh1/71.7 (IgM), Sh2/15.F (IgG(1)), Sh3/15.28 (IgG(1)), Sh3/38.2 (IgM), Sh4/14.3 (IgG(1)), and Sh5/32.30 (IgM)] produced against S. haematobium were extensively characterized. All the MAbs stained the surface membranes of miracidia as determined by the indirect fluorescent antibody test, yet three of them (Sh1/71.7, Sh3/15.28, and Sh3/38.2) also stained internal cytoplasmic antigens. Proteinase-K digestion and periodate oxidation studies showed that these three MAbs bound glycoprotein antigenic determinants, while the rest detected protein epitopes. Only Sh2/15.F, Sh3/15.28, and Sh4/14.3 could bind antigens with the western immunoblot assay. Sh2/15.F bound a 29-kDa antigen and Sh3/15.28 bound three antigen bands (53, 57, and 66 MDa) all in the soluble egg extract of an Egyptian strain of S. haematobium (SEA(Egy)), while Sh4/14.3 reacted with a 29-kDa antigen present in SEA(Egy) as well as in the adult worm antigen extracts of Ghanaian strain(s) of S. haematobium and S. japonicum. Sh4/14.3 also bound a 78-kDa antigen in the S. japonicum worm. Cross-reactivity studies with S. haematobium, S. mansoni, S. japonicum, and Necator americanus revealed that Sh2/15.F and Sh3/15.28 were S. haematobium species-specific. Each of the remaining MAbs detected the three major human schistosomes without cross-reacting with N. americanus egg antigens. Three MAbs, Sh2/15.F, Sh4/14.3 and Sh5/32.30, could detect S. haematobium antigens in infected human urine.