Abstract
A synthetic multivalent hemagglutinin and neuraminidase inhibitor was developed by the conjugation of a septa-valent triazolylsialoside to bovine serum albumin using di-(N-succinimidyl) adipate. Matrixassisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) confirmed the attachment of five septa-valent sialyl lactosides to the protein backbone, resulting in a pentatrideca-valent sialyl conjugate. This pseudo-glycoprotein demonstrated a high affinity for hemagglutinin/neuraminidase as well as for the drug-resistant NA mutation on the influenza virus surface due to the cluster effect. The conjugate also exhibited potent antiviral activity against a wide range of virus strains without cytotoxicity at high concentrations. Mechanistic studies revealed that the pentatrideca-valent sialyl conjugate bound strongly to the influenza virion particles through interactions with HA/NA on the virion surfaces. The KD of the interaction was approximately 1 μM, as determined by isothermal calorimetric titration, allowing the capture and trapping of the influenza virions and preventing their further infection of host cells. These findings provide insight into the development of new antiviral agents using multivalent sialic acid clusters.