Schistosoma mansoni is one of the three major parasitic blood flukes and causes a hepatosplenic disease in humans. Glycoproteins from S. mansoni adults and larvae are antigenic in infected animals and some carbohydrate moieties are antigenic. Recent studies have demonstrated that glycoproteins synthesized by adult male schistosomes contain O- and N-linked sugar chains, and that the O-linked chains are simple mono- and disaccharide species related in structure to those in human-derived glycoproteins. In contrast, preliminary studies suggest that the complex-type N-linked chains in glycoproteins from adult males are highly atypical in structure. These studies have led to the present proposal to investigate in detail the structure and immunogenicity of oligosaccharides in glycoproteins made by S. mansoni. 1. The N-linked chains in glycoproteins synthesized by adult male and female schistosomes and schistosomula will be isolated and structurally characterized. Newly synthesized sugar chains will be metabolically-radiolabeled with radioactive precursor sugars. The oligosaccharides will be liberated from glycoproteins and then isolated and fractionated by lectin affinity chromatography and HPLC and their structures will be defined by a variety of techniques. 2. Structurally unusual N-linked chains identified in the research above will be isolated in large quantities from adult organisms and covalently attached to carrier proteins to allow for the preparation of murine monoclonal antibodies to the sugar chains. The carbohydrate epitopes recognized by the antibodies will be investigated. 3. The antibodies will be used to probe the distribution of antigenic sugar chains on different glycoproteins and glycolipids by immunoblotting and immunostaining, respectively, against preparations from whole organisms at different developmental stages. These antibodies will also be used to precipitate newly synthesized glycoproteins from the organisms to study possible stage-specific glycoprotein biosynthesis. 4. The anatomical location of the antigenic carbohydrate structures on glycoproteins in the organisms at many stages of development will be probed. These studies should provide valuable new information and tools for further research into the cell biology and biochemistry of S. mansoni and provide new reagents for possible immunoprophylaxis and serodiagnosis of schistosomiasis.
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