Sialic acid receptor (SA receptor) (SA receptor)

The influenza A hemagglutinin receptor-binding site on host cells refers to the sialic acid (N-acetylneuraminic acid) residues located on the terminal ends of cell-surface glycans. These residues serve as the essential attachment point for the influenza A virus hemagglutinin (HA) protein, initiating the process of viral entry and infection [1]. The specificity of the interaction depends on the linkage of the sialic acid to the underlying galactose; human influenza viruses typically prefer alpha-2,6-linkages found in the upper respiratory tract, while avian viruses prefer alpha-2,3-linkages [2]. Because this interaction is the first step of the viral life cycle, it is a major target for therapeutic intervention. Drugs like DAS181 (Fludase) act as sialidases that enzymatically remove these receptors from the host cell surface, thereby creating a physical barrier to viral attachment [3]. This host-targeted approach is advantageous as it remains effective against various viral strains and subtypes, including those resistant to traditional neuraminidase inhibitors [4]. However, since sialic acids are involved in numerous host biological functions, such as cell signaling and protein stability, therapeutic strategies must balance efficacy with potential safety concerns [5]. Sources: [1] Skehel, J. J., & Wiley, D. C. (2000). Receptor binding and membrane fusion in virus entry: the influenza hemagglutinin. Annual Review of Biochemistry. [2] Shinya, K., et al. (2006). Avian flu: influenza virus receptors in the human airway. Nature. [3] Malakhov, M. P., et al. (2006). Sialidase fusion protein as a novel broad-spectrum antiviral agent. Antimicrobial Agents and Chemotherapy. [4] Triana-Baltzer, G. B., et al. (2009). DAS181, a sialidase fusion protein, protects mice from lethal avian influenza H5N1 virus infection. Journal of Infectious Diseases. [5] Varki, A. (2008). Sialic acids in human health and disease. Trends in Molecular Medicine.

Other names

N-acetylneuraminic acid receptorInfluenza virus receptorAlpha-2,3-sialic acidAlpha-2,6-sialic acidNeu5AcSialic acid-containing glycan

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