Alpha-2,6-linked sialic acid receptor (alpha2,6-SA)

Human upper respiratory tract epithelial cell sialic acid receptors, specifically those with alpha-2,6-linkages (Neu5Ac-alpha-2,6-Gal), are critical glycan structures located on the surface of host cells. These receptors serve as the primary docking sites for human-adapted influenza viruses, where the viral hemagglutinin protein binds to the sialic acid to initiate endocytosis and infection (Shinya et al., 2006, Nature). The distribution of these receptors is a key determinant of viral tropism; while alpha-2,6-linked sialic acids predominate in the human upper respiratory tract, alpha-2,3-linked sialic acids are more common in the lower respiratory tract and avian species (Nicholls et al., 2007, Respiratory Research). Beyond influenza, these receptors are involved in the attachment of other respiratory pathogens, including certain rhinoviruses and coronaviruses. From a therapeutic perspective, these receptors are the target of host-directed antivirals like DAS181 (Fludase), a recombinant sialidase that cleaves the sialic acid residues to prevent viral entry (Triana-Falo et al., 2019, Antiviral Research). Because they are host-encoded, these receptors are less prone to the rapid mutational escape seen with direct-acting antivirals that target viral proteins.

Other names

Neu5Ac-alpha-2,6-Gal6'-sialyllactoseHuman-type influenza receptorSialic acid-alpha-2,6-galactoseHuman upper respiratory tract sialic acid receptor

Enzymatic desialylation of the respiratory epithelium to remove the terminal sialic acid residues required for viral binding and entry.