title: Generation and characterization of recombinant influenza A (H1N1) viruses harboring amantadine resistance mutations.
abstract: The emergence of resistance to amantadine in influenza A viruses has been shown to occur rapidly during treatment as a result of single-amino-acid substitutions at position 26, 27, 30, 31, or 34 within the transmembrane domain of the matrix-(M)-2 protein. In this study, reverse genetics was used to generate and characterize recombinant influenza A (H1N1) viruses harboring L26F, V27A, A30T, S31N, G34E, and V27A/S31N mutations in the M2 gene. In plaque reduction assays, all mutations conferred amantadine resistance, with drug concentrations resulting in reduction of plaque number by 50% (IC(50)s) 154- to 3,300-fold higher than those seen for the wild type (WT). M2 mutants had no impairment in their replicative capacities in vitro on the basis of plaque size and replication kinetics experiments. In addition, all mutants were at least as virulent as the WT in experimentally infected mice, with the highest mortality rate being obtained with the recombinant harboring a double V27A/S31N mutation. These findings could help explain the frequent emergence and transmission of amantadine-resistant influenza viruses during antiviral pressure in the clinical setting.
authors.affiliation: Research Center in Infectious Diseases of the CHUQ-CHUL and Laval University, Québec City, Canada.
authors.forename: Yacine
authors.initials: Y
authors.lastname: Abed
authors.forename: Nathalie
authors.initials: N
authors.lastname: Goyette
authors.forename: Guy
authors.initials: G
authors.lastname: Boivin
mesh_terms: D000547:Amantadine / Q000494:pharmacology*; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D002417:Cattle; D002460:Cell Line; D024882:Drug Resistance, Viral; D005260:Female; D053118:Influenza A Virus, H1N1 Subtype; D009980:Influenza A virus / Q000187:drug effects* / Q000235:genetics* / Q000472:pathogenicity; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D011995:Recombination, Genetic; D014763:Viral Matrix Proteins / Q000235:genetics*; D014774:Virulence; D000086082:Viroporin Proteins
chemical_list: D000547:Amantadine; D000998:Antiviral Agents; D014763:Viral Matrix Proteins; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins