Characterization of fucosyllactose determinant-bearing glycoproteins probed by a Biomphalaria alexandrina lectin in Schistosoma mansoni cercariae.
Utilizing a Biomphalaria alexandrina-derived lectin (BaSII) of proven specificity to a Schistosoma mansoni-associated fucosyllactose [(Fuc alpha 1-2) Gal beta 1-4 Glc] determinant, two determinant-bearing glycoproteins of 40 and 37 kDa were found to be synthesized by the cercarial stage of the parasite. The two glycoproteins were isolated by BaSII affinity column chromatography from extracts of cercariae metabolically radiolabelled with 35S-methionine. Treatments with endoglycosidases, alkaline borohydride, as well as concanavalin A column chromatography and analysis by two-dimensional gels indicated that the two glycoproteins are synthesized as a single 33 kDa polypeptide backbone that is differentially glycosylated with one and/or two determinant-bearing N-linked complex-type glycan units of either the biantennary, or, to a lesser extent, the tri- or tetra-antennary types. The two glycoproteins lack other conventional high mannose-type or O-linked glycans, and the distinct structures of the complex-type oligosaccharides accounted solely for the expression of three isomorphs for each determinant-bearing glycoprotein. Based on the structural relatedness of the fucosyllactose determinant to the antigenic mammalian blood group H trisaccharide, our observations may have implications in mechanisms of host-parasite interactions as well as immunoprophylaxis.
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Department of Zoology, Faculty of Science, Monoufia University, Shebin El Kom, Egypt.
D000818:Animals; D000947:Antigens, Helminth / Q000737:chemistry* / Q000276:immunology; D002240:Carbohydrate Sequence; D002846:Chromatography, Affinity; D015180:Electrophoresis, Gel, Two-Dimensional; D000939:Epitopes / Q000737:chemistry* / Q000276:immunology; D006023:Glycoproteins / Q000737:chemistry* / Q000276:immunology; D037102:Lectins; D008969:Molecular Sequence Data; D012550:Schistosoma mansoni / Q000737:chemistry* / Q000254:growth & development / Q000276:immunology; D014312:Trisaccharides / Q000302:isolation & purification*
D000947:Antigens, Helminth; D000939:Epitopes; D006023:Glycoproteins; D037102:Lectins; D014312:Trisaccharides