Presence of an Al,3 fucosyltransferase (Fuc to GlcNAc) in the helminthic parasite, Haemonchus contortus

We recently demonstrated that the helminthic parasite Schistosoma mansoni contains an a 1,3 fucosyltransferase (al,3FT) that causes synthesis of the Lewis x antigen (£ex) Gal#l-4(Fucal-3)GlcNAc-R and a related structure GalNAc/5l-4(FucQl-3)GlcNAc-R (GalNAc-Iex-type). This latter structure is also synthesized by the dog heartworm Diroβlaria immitis. These fucosylated glycans have been implicated in several aspects of the host-parasite interactions. To explore the possibility that other helminthic parasites contain an al,3FT. we have assayed the al,3FT activity in detergent extracts of H. Contortus, a parasitic nematode which dwells in the gut of ruminants. An extract of this parasite contains high levels of an al,3FT that efficiently uses lacto-N-neotetraose GaL3l-4GlcNAcβl-3Gal#l-4Glc as an acceptor to synthesize lacto-N-fucopentaose III Gal01-4(Fucal-3)GlcNAcβl-3Galβl-4Glc. The product was characterized by Dionex HPAEC co-chromatography with standards and by sensitivity to an al-3/al-4-specific fucosidase. Lectin binding studies also reveal that H. contortus glycoproteins contain the GalNAc-IeTtype structures. These results signify that the ul,3FT and the GalNAc-ie1type structures are general features of the biosynthetic pathways for glycoconjugates in helminths.