title: Characterization of human H1N1 influenza virus variants selected in vitro with zanamivir in the presence of sialic acid-containing molecules.
abstract: Understanding the molecular mechanisms of influenza virus resistance to neuraminidase inhibitors is a main concern for their clinical use. In an attempt to reproduce in vivo selective conditions where influenza virus resistance to neuraminidase inhibitors can occur the zanamivir selection of an A/H1N1 influenza virus strain was carried out in Madin-Darby canine kidney cells performed in the presence or absence of sialic acid-containing inhibitor analogues that act as virus decoy receptors. The zanamivir-selected variants passaged in the presence of sialic acid-containing molecules resembling the human-like virus receptor lost the ability to bind red blood cells. Furthermore, whereas all zanamivir-selected variants exhibited a robust reduction in susceptibility to zanamivir in plaque assays only those obtained after extensive passages acquired a powerful neuraminidase enzyme resistance to zanamivir and oseltamivir. Evidence that balanced neuraminidase and hemagglutinin activities mediated by mutations induced during selection could play a role in the decrease of virus replication susceptibility to zanamivir is reported.
authors.affiliation: Virology Unit, Department of Public Health, University of Florence, I-50134 Florence, Italy. simone.giannecchini@unifi.it
authors.forename: Simone
authors.initials: S
authors.lastname: Giannecchini
authors.forename: Laura
authors.initials: L
authors.lastname: Campitelli
authors.forename: Giacomo
authors.initials: G
authors.lastname: Bandini
authors.forename: Isabella
authors.initials: I
authors.lastname: Donatelli
authors.forename: Alberta
authors.initials: A
authors.lastname: Azzi
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D002460:Cell Line; D024882:Drug Resistance, Viral; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology*; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000378:metabolism; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D009154:Mutation; D009439:Neuraminidase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D053139:Oseltamivir / Q000494:pharmacology; D012794:Sialic Acids / Q000378:metabolism*; D010948:Viral Plaque Assay; D014779:Virus Replication; D053243:Zanamivir / Q000494:pharmacology*
chemical_list: D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D012794:Sialic Acids; D053139:Oseltamivir; D009439:Neuraminidase; D053243:Zanamivir