Glycosphingolipids from the parasitic liver flukes F a sciola gigantica and Fasciola hepatica w e re isolated and their carbohydrate moieties were structurally analysed by methylation analysis, exoglycosidase t reatment, ontarget exoglycosidase cleavage and matrixassisted laser desorption/ionisation timeofflight mass spectrometry. For both liver fluke species, the ceramide monohexosides Gal1-ceramide and Glc1-ceramide were found in relative amounts of 1.0 to 0.1, respectively. From F. gigantica, the ceramide dihexoside was isolated in sufficient amounts to be structurally determined as lactosylceramide, Gal?4- Glc1-ceramide, while for both liver fluke species the ceramide trihexoside was shown to be Gal?4 G a lb4- Glc1-ceramide, which is designated as either globotriaosylceramide, Pblood group antigen or CD77 leucocyte cluster of diff e rentiation antigen. To our knowledge, this is the first report on the expression of globoseries glycosphingolipids in nonmammalian species. Ceramide analysis of ceramide monohexosides yielded as major components octadecanoic and 2 h y d roxyoctadecanoic fatty acids together with C18- and C20-phytosphingosines. By the use of an anti CD77 monoclonal antibody and the Escherichia coli Shiga toxin B1 subunit, globotriaosylceramide could be immunolocalised to the tegument of F. hepatica cryosections. The sharing of CD77 between liver flukes and their mammalian hosts fits in with the concept of molecular mimicry, which is closely parallel to the established imitation of host CD15 (Lewis X) displayed by the blood fluke Schistosoma mansoni.
Print ISSN: 1431-6730
Volume: 382, 03/2001
Pages: 195 - 207