A sialic acid analogue acting as a receptor determinant for binding but not for infection by influenza C virus

Abstract
We describe a synthetic sialic acid analogue, 9‐thioacetamido‐N‐acetylneuraminic acid (9‐thioacetamido‐Neu5Ac), which is recognized by the receptor‐binding activity of influenza C virus, but is resistant to the receptor‐destroying enzyme (acetylesterase) of this virus. Following transfer of the analogue to the surface of receptor‐negative cells, influenza C virus is able to attach to these cells, but is unable to infect the cells. This result suggests that inactivation of virus receptors by the receptor‐destroying enzyme is essential for initiation of infection. Because of their unique properties such analogues promise to be powerful chemotherapeutic agents.