Sialic acid-terminated glycan receptor (SA-glycan receptor)

Sialic acid-terminated glycan receptors are carbohydrate structures found on the surface of various cells, including human respiratory epithelial cells and erythrocytes. These glycans, typically terminating in N-acetylneuraminic acid (Neu5Ac) linked to galactose via alpha-2,6 or alpha-2,3 bonds, serve as the primary attachment points for many respiratory pathogens, most notably the influenza virus (PubMed: 31434738). In humans, alpha-2,6-linked sialic acids are predominant in the upper respiratory tract, while alpha-2,3-linked sialic acids are more common in the lower respiratory tract and are the preferred receptors for avian influenza strains (PubMed: 16543414). On erythrocytes, these receptors facilitate hemagglutination, a process used extensively in virological assays to detect and quantify virus particles. Because these receptors are essential for viral entry into the respiratory epithelium, they have become a focus for host-directed therapeutic interventions. Drugs like DAS181 (a recombinant sialidase) work by enzymatically removing these terminal sialic acids from the cell surface. This enzymatic action effectively masks the host cells from viral recognition, thereby preventing viral attachment and subsequent infection (PubMed: 21149487). This approach is particularly valuable as it targets a host factor, potentially reducing the likelihood of viral resistance compared to drugs targeting viral proteins.

Other names

Sialic acid receptorSialylated glycanNeu5Ac-terminated glycanAlpha-2,6-linked sialic acidAlpha-2,3-linked sialic acidSialic acid-terminated glycan receptors on human respiratory epithelial cells and erythrocytes

Enzymatic cleavage of terminal sialic acid residues from the host cell surface to prevent viral attachment and entry.