Anti-influenza virus activity of high-mannose binding lectins derived from genus Pseudomonas

Abstract Lectin PFL binding high-mannose glycan derived from Pseudomonas fluorescens and other homologous lectins: PML derived from Pseudomonas mandelii and PTL derived from Pseudomonas taiwanensis were examined for antiviral activity. The cDNA of these lectin genes were synthesized, cloned, expressed in Escherichia coli . The expressed lectins were purified by gel filtrations, and supplied to cultures infected with several strains of influenza virus. These three lectins have inhibited propagation of influenza viruses with a similar extent, 50% of inhibition-dose was around ten nanomolar concentration. An immunofluorescent microscopy, a microarray analysis, and several infection experiments with different time periods of lectin addition or using the competitor substrates indicated that binding of these lectins with high-mannose glycan on HA protein of influenza virus could block the virus entry into the host cells, thereby resulting in inhibition of the virus propagation. These Pseudomonas -derived lectins would be protential and attractive antiviral agents targeting glycoproteins of enveloped viruses including influenza virus.