Alpha-2,3-linked sialic acid receptor (alpha2,3-SA receptor)

Alpha-2,3-linked sialic acid receptors are the primary host cell attachment sites for the hemagglutinin (HA) protein of the H5N1 A/Indonesia/05/2005 influenza virus (Stevens et al., Science, 2006). These receptors consist of N-acetylneuraminic acid linked to galactose via an alpha-2,3 glycosidic bond, a configuration predominantly found in the avian enteric tract and the human lower respiratory tract (Shinya et al., Nature, 2006). The HA of the A/Indonesia/05/2005 strain specifically recognizes these glycans to initiate viral entry via endocytosis, contributing to the virus's high pathogenicity and its ability to cause severe pneumonia in humans (Maines et al., J. Virol., 2006). Because these receptors are less prevalent in the human upper respiratory tract compared to alpha-2,6-linked sialic acids, H5N1 transmission between humans remains inefficient (Walther et al., PLoS Pathogens, 2013). Therapeutic interventions targeting this receptor include DAS181, a recombinant sialidase that removes sialic acid from the cell surface to prevent viral docking. Understanding the interaction between H5N1 HA and these receptors is vital for developing entry inhibitors and assessing the pandemic risk of emerging avian influenza strains.

Other names

Neu5Ac-alpha-2,3-GalAvian influenza receptorSialyl-alpha-2,3-galactoseH5N1 receptor

Enzymatic cleavage of sialic acid residues from host cell surfaces to prevent viral attachment or inhibition of hemagglutinin-mediated membrane fusion.