Host cell sialic acid-terminated glycans (SA-glycans)

Host cell sialic acid-terminated glycans are complex carbohydrate structures found at the terminal positions of glycoproteins and glycolipids on the cell surface. These nine-carbon acidic sugars, most commonly N-acetylneuraminic acid (Neu5Ac), are essential for various biological processes, including cell-to-cell communication and the regulation of the immune system (Varki, A., 2008, Glycobiology). They serve as the primary attachment receptors for a wide range of pathogens, most notably influenza viruses, which utilize their hemagglutinin protein to bind specific sialic acid linkages—typically alpha 2-6 for human-adapted strains and alpha 2-3 for avian strains (Shinya, K., et al., 2006, Nature). Beyond viral entry, hypersialylation is a recognized hallmark of cancer, where it contributes to tumor metastasis and immune evasion by interacting with sialic acid-binding immunoglobulin-type lectins (Siglecs) on immune cells (Pearce, O. M., & Läubli, H., 2016, Glycobiology). Therapeutic strategies targeting these glycans include the use of DAS181 (Fludase), a recombinant sialidase that enzymatically strips sialic acids from the respiratory epithelium to block viral infection (Moss, R. B., et al., 2012, Journal of Infectious Diseases). Additionally, neuraminidase inhibitors like oseltamivir work by preventing the viral enzyme from cleaving these host glycans, which is a necessary step for the release of new viral particles from the infected cell.

Other names

Sialylated glycansSialic acid receptorsN-acetylneuraminic acid-terminated glycansSialosidesTerminal sialic acidsNeu5Ac-terminated glycans

Enzymatic removal of terminal sialic acid residues from host cell surfaces to prevent viral attachment and entry; or inhibition of viral neuraminidase to prevent the cleavage of these glycans, thereby trapping progeny virions on the host cell surface.