Figure 10.27 Viral receptors. (A) Influenza virus targets cells by binding to sialic acid residues located at the termini of oligosaccharides present on cell-surface glycoproteins and glycolipids. These carbohydrates are bound by hemagglutinin, one of the major proteins expressed on the surface of the virus. (B) When viral replication is complete and the viral particle buds from the cell, the other major viral-surface protein, neuraminidase cleaves oligosaccharide chains to release the viral particle.