Susceptibility of Virus Clones to AMT, OSC, RBV and ZAN as Single Agents.

Wild type influenza A/Hawaii/31/07 (H1N1) virus was passaged in the presence of escalating concentrations of each drug regimen, and the supernatant from selected passages from each regimen was sequenced by the Sanger method at the M2, hemagglutinin (HA), and/or neuraminidase (NA) genes to detect the presence of mutations. Six virus clones were isolated from each regimen (from the latest passage that yielded viable plaques) and were sequenced at M2, HA, and NA to confirm that the genotype of the clone matched that of the supernatant. The susceptibility of clones bearing representative substitutions to AMT, OSC, RBV, and ZAN was tested using neutral red assay.
aEach drug was tested using two plates, with 3 replicate wells per plate. EC50 values are the mean of duplicate plates with standard deviations.
bNo drug control passaged in parallel.
cAmino acid positions in HA are designated using universal H3 numbering [42].