Characterization of mutants of influenza A virus selected with the neuraminidase inhibitor 4-guanidino-Neu5Ac2en.

摘要: The development of viral resistance to the neuraminidase (NA) inhibitor, 4-guanidino-Neu5Ac2en, influenza viruses was studied by serial passage A/Turkey/Minnesota/833/80 (H4N2) in Madin-Darby canine kidney cells presence increasing concentrations inhibitor. Resistant mutants selected after eight passages, had a 10,000-fold reduction sensitivity inhibitor plaque assays, but their affinity (1/Kd) similar that parental virus. Electron microscopic analysis revealed aggregation mutant virus at cell surface Sequence established substitution occurred NA (Arg-249 Lys) and HA2 subunit hemagglutinin (Gly-75 Glu), vicinity proposed second sialic acid binding site. change residue 249 appears be chance mutation, for we were unable reisolate this mutant, whereas subsequent experiments indicate changes hemagglutinin. After 13 passages virus, resistant high tested obtained. These retained drug-resistant phenotype even five without no on infected gene from these an additional Glu Ala conserved amino 119. This is responsible reducing NA. Our findings suggest emergence 4-guanidine-Neu5Ac2en multistep process requiring prolonged exposure