Alpha-2,6-linked sialic acid (α2,6-Sia)

Alpha-2,6-linked sialic acids are terminal monosaccharides found on the glycoconjugates of host cell surfaces, particularly in the human upper respiratory tract (Shinya et al., Nature 2006). They serve as the primary attachment point for human-adapted influenza viruses, which utilize their hemagglutinin protein to recognize and bind these specific glycan structures (Matrosovich et al., PNAS 2000). In addition to their role in viral pathogenesis, these linkages are involved in various physiological processes, including cell-cell recognition and the modulation of immune responses (Varki et al., Essentials of Glycobiology). Therapeutic strategies targeting these glycans often involve the use of recombinant sialidases, such as DAS181 (Fludase), which cleave the sialic acid residues to prevent viral entry (Belser et al., JID 2007). Furthermore, alterations in the expression of alpha-2,6-linked sialic acids are frequently observed in malignant cells, where they contribute to tumor progression and immune evasion (Bull et al., Cancer Research 2014). Understanding the distribution and density of these receptors is crucial for predicting the pandemic potential of emerging avian influenza strains, which typically prefer alpha-2,3 linkages.

Other names

Neu5Acα2-6Galα2-6 sialylglycanHuman influenza virus receptor6'-sialyllactoseAlpha-2,6-Neu5Ac

The primary mechanism of action for drugs targeting these glycoconjugates involves the enzymatic removal of terminal sialic acid residues from the host cell surface using recombinant sialidases, thereby eliminating the binding sites for viral hemagglutinin and preventing viral entry. Alternatively, viral neuraminidase inhibitors prevent the cleavage of these sialic acid linkages, which traps newly formed virions on the host cell surface and prevents the spread of infection.