Fig. 2

Scheme of a model complex-type glycan showing presented oligosaccharide structures. An example of an N-glycan bearing the three glycoepitopes immunogenic in the mammalian hosts are shown. The αGal epitope is formed by a terminal galactose bound to another galactose via an α1-3 bond. In the case of the core α1,3-fucose, both the specific α1,3 bond and the core (not terminal localization of fucose are important for the immunogenicity in mammals. Two types of sialic acid are present in Eukaryotes: the N-acetylneuraminic acid (Neu5Ac) and the N-glycolylneuraminic acid (Neu5Gc). As humans do not possess the enzymatic apparatus for the production of Neu5Gc into glycans, glycans terminated with this type of sialic acid are immunogenic in humans. The used symbol nomenclature is based on the Consortium for Functional Glycomics (http://www.functionalglycomics.org/)