Glycoprofile of the different cell types present in the mucosa of the horse guttural pouches.
Histochemical characterization of the equine guttural pouches was performed using lectins combined with sialidase digestion and deglycosylation pre-treatments. The goblet cells contained O- and N-linked oligosaccharides with alpha-Fuc, GlcNAc moieties whereas beta-GalNAc, beta-Gal-(1-3)-GalNAc, beta-Gal-(1-4)-GlcNAc and alpha-Gal residues belonged only to O-linked glycoproteins. The acinar and ductal cells expressed alpha-Man/alpha-Glc in N-linked oligosaccharides, GlcNAc in both O- and N-glycoproteins and beta-GalNAc, beta-Gal-(1-3)-GalNAc, beta-Gal-(1-4)-GlcNAc and alpha-Gal residues included in O-linked glycoproteins. The Golgi area of the epithelial lining expressed alpha-Fuc in O-linked glycoproteins, internal GlcNAc in N-linked glycoproteins and large amounts of sialic acid residues linked to subterminal beta-GalNAc, Galbeta1,4GlcNAc and Galbeta1,3GalNAc. High amounts of sulpho-carbohydrates and of sialic acids (alpha2,3-6), linked to-alpha/beta-Gal and sialic acids (alpha2-6) linked to beta-GalNAc, were also demonstrated. Such diversity of the mucin saccharide residues may be implicated in the binding of macromolecules such as those of bacterial or viral etiology, thus playing a role in the organism's host-defense mechanism in the guttural pouches.