title: A single E105K mutation far from the active site of influenza B virus neuraminidase contributes to reduced susceptibility to multiple neuraminidase-inhibitor drugs.
abstract: Drugs inhibiting the enzymatic activity of influenza virus neuraminidase (NA) are the cornerstone of therapy for influenza virus infection. The emergence of drug-resistant variants may limit the benefits of antiviral therapy. Here we report the recovery of an influenza B virus with reduced susceptibilities to NA inhibitors from a human patient with no history of antiviral drug treatment. The virus, designated B/Kochi/61/2011, was isolated by inoculating Madin-Darby canine kidney (MDCK) cells with respiratory specimens from the patient. NA inhibition assays demonstrated that the B/Kochi/61/2011 isolate showed a remarkable reduction in susceptibility to peramivir. The isolate also exhibited low to moderately reduced sensitivity to oseltamivir, laninamivir, and zanamivir. A sequence analysis of viruses propagated in MDCK cells revealed that the isolate contained a mutation (E105K) not previously associated with reduced susceptibility to NA inhibitors. However, pyrosequencing analysis showed that the NA E105K mutation was below a detectable level in the original clinical specimens, suggesting that the mutant virus may be preferably selected during propagation in MDCK cells. Analysis of the three-dimensional model of E105 and K105 NAs with peramivir suggested that the E105K mutation at the monomer-monomer interface of the NA tetramer may destabilize the tetrameric form of NA, leading to decreased susceptibility to NA inhibitors. These results have implications for understanding the mechanism of resistance against NA-inhibitor drugs.
authors.affiliation: Laboratory of Influenza Virus Surveillance, Influenza Virus Research Center, National Institute of Infectious Diseases, Tokyo 208-0011, Japan.
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Fujisaki
authors.forename: Emi
authors.initials: E
authors.lastname: Takashita
authors.forename: Masaru
authors.initials: M
authors.lastname: Yokoyama
authors.forename: Tae
authors.initials: T
authors.lastname: Taniwaki
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
authors.forename: Noriko
authors.initials: N
authors.lastname: Kishida
authors.forename: Hironori
authors.initials: H
authors.lastname: Sato
authors.forename: Masato
authors.initials: M
authors.lastname: Tashiro
authors.forename: Masaki
authors.initials: M
authors.lastname: Imai
authors.forename: Takato
authors.initials: T
authors.lastname: Odagiri
mesh_terms: D000146:Acids, Carbocyclic; D000818:Animals; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology*; D020134:Catalytic Domain / Q000235:genetics; D003517:Cyclopentanes / Q000737:chemistry / Q000494:pharmacology; D004285:Dogs; D024882:Drug Resistance, Viral / Q000235:genetics*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D006146:Guanidines / Q000737:chemistry / Q000494:pharmacology; D057809:HEK293 Cells; D006801:Humans; D009981:Influenza B virus / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D061985:Madin Darby Canine Kidney Cells; D008958:Models, Molecular; D009154:Mutation; D009439:Neuraminidase / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics*; D053139:Oseltamivir / Q000737:chemistry / Q000494:pharmacology; D011487:Protein Conformation; D011714:Pyrans; D012794:Sialic Acids; D014764:Viral Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics*; D053243:Zanamivir / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000146:Acids, Carbocyclic; D000998:Antiviral Agents; D003517:Cyclopentanes; D004791:Enzyme Inhibitors; D006146:Guanidines; D011714:Pyrans; D012794:Sialic Acids; D014764:Viral Proteins; D053139:Oseltamivir; C546918:laninamivir; C541223:NA protein, influenza B virus; D009439:Neuraminidase; D053243:Zanamivir; C414210:peramivir