Synthesis of neoglycoproteins containing O-methylated trisaccharides related to excretory/secretory antigens of Toxocara larvae Original Research Article

The disaccharides allyl β-d-galactopyranosyl-(1→3)-2-acetamido-2-deoxy-β- and α-d-galactopyranoside 10a and 10b and the trisaccharides allyl 2-O-methyl-α-l-fucopyranosyl-(1→2)-β-d-galactopyranosyl-(1→3)-2-acetamido-2-deoxy-β- and α-d-galactopyranoside 18a and 18b have been prepared using stepwise assembly of the sugar units. The glycosidic linkages were formed employing the trichloroacetimidate procedure for the attachment of the galactopyranosyl residue and N-iodosuccinimide/triflic acid activation of an ethyl 1-thiofucopyranoside donor for fucosylation. Deprotection furnished the allyl glycosides which were converted into cysteamine-spacered ligands, activated with thiophosgene and subsequently linked to bovine serum albumin. The neoglycoproteins serve as immunoreagents to determine epitope specificities of monoclonal antibodies directed against highly immunogenic O-glycans located at the surface of Toxocara larvae.