Synthesis, Antigenicity Against Human Sera and Structure-Activity Relationships of Carbohydrate Moieties from <em>Toxocara</em> larvae and Their Analogues

Abstract

Stereocontrolled syntheses of biotin-labeled oligosaccharide portions containing the Galβ1-3GalNAc core of the TES-glycoprotein antigen obtained from larvae of the parasite <em>Toxocara</em> and their analogues have been accomplished. Trisaccharides Fuc2Meα1-2Gal4Meβ1-3GalNAcα1-OR (<strong>A</strong>), Fucα1-2Gal4Meβ1-3GalNAcα1-OR (<strong>B</strong>), Fuc2Meα1-2Galβ1-3GalNAcα1-OR (<strong>C</strong>), Fucα1-2Galβ1-3GalNAcα1-OR (<strong>D</strong>) and a disaccharide Fuc2Meα1-2Gal4Meβ1-OR (<strong>E</strong>) (R = biotinylated probe) were synthesized by block synthesis using 5-(methoxycarbonyl)pentyl-2,3,4,6-tetra-<em>O</em>-acetyl-β-D-galactopyranosyl-(1®3)-2-azide-4-<em>O</em>-benzyl-2-deoxy-α-D-galactopyranoside as a common glycosyl acceptor. We examined the antigenicity of these five oligosaccharides by enzyme linked immunosorbent assay (ELISA). Our results demonstrate that the <em>O</em>-methyl groups in these oligosaccharides are important for their antigenicity and the biotinylated oligosaccharides <strong>A</strong>, <strong>B</strong>, <strong>C</strong> and <strong>E</strong> have high serodiagnostic potential to detect infections caused by <em>Toxocara</em> larvae.

Keywords

• glycoprotein
• &lt;em&gt;Toxocara&lt;/em&gt; larvae
• host-parasite interaction
• stereocontrolled synthesis
• antigenicity