Carbohydrate recognition in the immune system: contributions of neoglycolipid-based microarrays to carbohydrate ligand discovery.
Bottom Line: The pinpointing and characterizing of oligosaccharide ligands within glycomes has been one of the most challenging aspects of molecular cell biology, as oligosaccharides cannot be cloned and are generally available in limited amounts.This overview recounts the background to the development of a microarray system that is poised for surveying proteomes for carbohydrate-binding activities and glycomes for assigning the oligosaccharide ligands.Particularly highlighted are sulfo-oligosaccharide and gluco-oligosaccharide recognition systems elucidated using microarrays.
Affiliation: The Glycosciences Laboratory, Department of Medicine, Imperial College London, London, United Kingdom. email@example.comShow MeSH
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Mentions: Dectin-1, the major receptor of the innate immune system against fungal pathogens is a C-type lectin-like protein on leukocytes.62 It has been reported to interact with a subset of T lymphocytes, but the main proven function for Dectin-1 is the mediation of phagocytosis and inflammatory mediator release in innate immunity to fungal pathogens. Although lacking in residues involved in calcium ligation that mediate carbohydrate binding by classical C-type lectins, Dectin-1 binds zymosan, a particulate β-glucan–rich extract of Saccharomyces cerevisiae; and binding is inhibited by polysaccharides rich in β1–3- or both β1–3- and β1–6-linked glucose.63 In order to prove that Dectin-1 binds to carbohydrates rather than to any polypeptides associated with the fungal cell walls and to identify the ligand structure(s), we generated designer probes, that is, NGLs, derived from oligosaccharides up to 13 mers isolated from partially depolymerized ligand-positive and ligand-negative glucan polysaccharides. These glucan probes were incorporated into microarrays.42 Upon probing the microarrays, the ligands for Dectin-1 were found to be unusually long, 10-mer or longer, β1–3-linked gluco-oligosaccharides. The β1–6-linked analogs were not bound (Fig. 3).42
Affiliation: The Glycosciences Laboratory, Department of Medicine, Imperial College London, London, United Kingdom. firstname.lastname@example.org