N-acetylneuraminic acid (Sialic acid receptor) (Neu5Ac)

N-acetylneuraminic acid (Neu5Ac), the most common form of sialic acid in humans, is a terminal nine-carbon monosaccharide found on the surface of host cell glycoproteins and glycolipids. It serves as a critical biological receptor for various pathogens, most notably the influenza virus, where it is recognized by the viral hemagglutinin protein for cell entry (Skehel & Wiley, 2000). Following viral replication, the viral neuraminidase enzyme cleaves these sialic acid residues to release newly synthesized virions from the host cell surface and prevent their entrapment by respiratory mucus (Varghese et al., 1992). This cleavage process is essential for the efficient spread of the virus to neighboring cells. Therapeutic strategies targeting this interaction include neuraminidase inhibitors (NAIs) like oseltamivir and zanamivir, which block the enzyme active site to prevent residue cleavage (von Itzstein, 2007). Additionally, host-directed therapies such as DAS181 (Fludase) utilize a recombinant sialidase to enzymatically strip these residues from the respiratory epithelium, thereby removing the viral docking site and preventing both infection and viral egress (Malakhov et al., 2006; Moss et al., 2012).

Other names

Sialic acidNeu5AcNeuraminic acidN-acetyl-alpha-neuraminic acidHost cell sialic acidInfluenza virus receptor

Enzymatic removal of terminal sialic acid residues from the host respiratory epithelium to prevent viral attachment and release (e.g., DAS181); or competitive inhibition of viral neuraminidase to prevent the cleavage of these residues from host cells and viral progeny (e.g., Oseltamivir) (von Itzstein, 2007; Moss et al., 2012).