α2,3- and α2,6-linked sialic acid–containing glycans (Sia-glycans)

α2,3- and α2,6-linked sialic acid–containing glycans are terminal carbohydrate structures found on the surface of host cell glycoproteins and glycolipids. These glycans serve as the critical primary receptors for various pathogens, most notably the influenza virus, where the viral hemagglutinin protein binds specifically to either α2,3 (avian-preferred) or α2,6 (human-preferred) linkages to initiate infection (Shinya et al., 2006, Nature). Beyond viral entry, these sialic acids play essential roles in cell-cell recognition, immune system modulation through interactions with Siglecs, and the regulation of glycoprotein stability (Pearce and Läubli, 2016, Glycobiology). In therapeutic contexts, these glycans are targeted indirectly by neuraminidase inhibitors like oseltamivir, which prevent the virus from cleaving these bonds to escape the host cell, or directly by sialidases like DAS181 that strip the receptors from the respiratory epithelium (Triana-Baltzer et al., 2009, PLoS ONE). Alterations in the density and linkage of these sialic acids, such as hypersialylation, are also observed in various cancers, contributing to tumor immune evasion and metastasis (Sieben et al., 2014, Journal of Virology).

Other names

Sialyl-glycansNeu5Ac-linked glycansInfluenza virus receptorsSialic acid receptorsTerminal sialic acidsSialylated glycoproteinsSialylated glycolipids

Inhibition of viral neuraminidase to prevent the cleavage of sialic acid linkages and viral release; enzymatic removal of sialic acid residues from host cell surfaces to prevent viral attachment; competitive inhibition of viral hemagglutinin binding.