lewis-x-antigen and Schistosomiasis

Genetic evidence suggests that the Schistosoma mansoni genome contains six genes that encode α1,3-fucosyltransferases (smFuTs). To date, the activities and specificities of these putative fucosyltransferases are unknown. As Schistosoma express a variety of fucosylated glycans, including the Lewis X antigen Galβ1-4(Fucα1-3)GlcNAcβ-R, it is likely that this family of genes encode enzymes that are partly responsible for the generation of those structures. Here, we report the molecular cloning of fucosyltransferase-F (smFuT-F) from S. mansoni, as a soluble, green fluorescent protein fusion protein and its acceptor specificity. The gene smFuT-F was expressed in HEK freestyle cells, purified by affinity chromatography, and analyzed toward a broad panel of glycan acceptors. The enzyme product of smFuT-F effectively utilizes a type II chain acceptor Galβ1-4GlcNAc-R, but notably not the LDN sequence GalNAcβ1-4GlcNAc-R, to generate Lewis X type-glycans, and smFuT-F transcripts are present in all intramammalian life stages.

Topics: Animals; Carbohydrate Sequence; Cloning, Molecular; Fucose; Fucosyltransferases; Lewis X Antigen; Polysaccharides; Schistosoma mansoni; Schistosomiasis

Schistosoma bovis is a parasite of wild and domestic ruminants that is broadly distributed throughout many tropical and temperate regions of the old world. S. bovis causes severe health problems and significant economic losses in livestock, but in contrast to human schistosomes, S. bovis has been little investigated at a molecular level. Since schistosome glycans and glycoproteins can play important roles in the host-parasite interplay, the aims of the present work were: (i) to characterize the glycans expressed by adult S. bovis worms on their excreted/secreted (ES) and tegumental (TG) glycoproteins and (ii) to identify their carrier protein backbones by mass spectrometry. Using a panel of lectins and monoclonal and polyclonal anti-glycan antibodies, we observed: (i) the absence of sialic acid in S. bovis; (ii) the presence of complex-type N-glycans and LDN antennae on ES glycoproteins; (iii) the presence of glycans containing the Fucalpha1-2Galbeta motif in many TG glycoproteins, and (iv) the presence of glycans containing the Fucalpha1-3GlcNAc motif on many ES and TG glycoproteins but, simultaneously, the absence of the F-LDN(-F) glycans from both the ES and TG glycoproteins. Interestingly, we also found the Lewis(X) and Lewis(Y) antigens co-expressed on several TG isoforms of ATP:guanidino kinase and glyceraldehyde-3-phosphate dehydrogenase. Finally, by ELISA we observed the presence of antibodies against Lewis(X), Lewis(Y) and F-LDN(-F) in the sera of sheep experimentally infected with S. bovis.

Topics: Animals; Antibodies, Helminth; Blotting, Western; Electrophoresis, Gel, Two-Dimensional; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Glycoproteins; Host-Parasite Interactions; Lectins; Lewis X Antigen; Mass Spectrometry; Polysaccharides; Schistosoma; Schistosomiasis; Sheep; Sheep Diseases; Snails

Adults of the human parasitic trematode Schistosoma mansoni, which causes hepatosplenic/intestinal complications in humans, synthesize glycoconjugates containing the Lewis x (Lex) Galbeta1-->4(Fucalpha1-->3)GlcNAcbeta1-->R, but not sialyl Lewis x (sLex), antigen. We now report on our analyses of Lexand sLexexpression in S.haematobium and S.japonicum, which are two other major species of human schistosomes that cause disease, and the possible autoimmunity to these antigens in infected individuals. Antigen expression was evaluated by both ELISA and Western blot analyses of detergent extracts of parasites using monoclonal antibodies. Several high molecular weight glycoproteins in both S. haematobium and S. japonicum contain the Lexantigen, but no sialyl Lexantigen was detected. In addition, sera from humans and rodents infected with S.haematobium and S.japonicum contain antibodies reactive with Lex. These results led us to investigate whether Lexantigens are expressed in other helminths, including the parasitic trematode Fasciola hepatica , the parasitic nematode Dirofilaria immitis (dog heartworm), the ruminant nematode Haemonchus contortus , and the free-living nematode Caenorhabditis elegans . Neither Lexnor sialyl-Lexis detectable in these other helminths. Furthermore, none of the helminths, including schistosomes, express Lea, Leb, Ley, or the H-type 1 antigen. However, several glycoproteins from all helminths analyzed are bound by Lotus tetragonolobus agglutinin , which binds Fucalpha1-->3GlcNAc, and Wisteria floribunda agglutinin, which binds GalNAcbeta1-->4GlcNAc (lacdiNAc or LDN). Thus, schistosomes may be unique among helminths in expressing the Lexantigen, whereas many different helminths may express alpha1,3-fucosylated glycans and the LDN motif.

Topics: Animals; Antibodies, Helminth; Antibody Formation; Antigens, Helminth; Blood; COS Cells; Disaccharides; Glycoconjugates; Glycoproteins; Helminth Proteins; Helminths; Humans; Lactose; Lewis Blood Group Antigens; Lewis X Antigen; Nematoda; Rodentia; Schistosoma haematobium; Schistosoma japonicum; Schistosomiasis; Trematoda