Host sialic acid receptors (SA receptors)

Host sialic acid receptors are terminal carbohydrate structures found on glycoproteins and glycolipids of the respiratory epithelium. They serve as the primary attachment point for the influenza virus hemagglutinin (HA) protein, which initiates the infection process (PubMed: 21760595). Human influenza viruses typically prefer alpha2,6-linked sialic acids found in the upper respiratory tract, while avian viruses prefer alpha2,3-linked sialic acids found in the lower respiratory tract (PubMed: 16439206). By binding to these receptors, the virus is internalized via endocytosis. Therapeutic strategies targeting these receptors include the use of sialidases to strip the receptors from the cell surface or small molecules and biologics that block the HA-binding site. For instance, the drug candidate DAS181 (Fludase) is a recombinant sialidase designed to remove these receptors to prevent viral entry (PubMed: 24109133). Understanding the distribution and specificity of these receptors is crucial for assessing the pandemic potential of emerging influenza strains. These receptors also play roles in host cell signaling and immune recognition, making them complex but vital targets for antiviral therapy.

Other names

Sialic acid-containing glycoconjugatesN-acetylneuraminic acid receptorsNeu5Ac receptorsInfluenza virus receptorsAlpha2,3-linked sialic acidAlpha2,6-linked sialic acid

Enzymatic cleavage of terminal sialic acid residues from host cell surface glycoproteins and glycolipids, which removes the essential binding sites for the influenza virus hemagglutinin protein and prevents viral attachment and entry.