TABLE 2.

Infectivities of recombinant A/Wuhan/359/95 (H3N2) influenza viruses with different NA mutations

VirusViral yieldRelative viral yield
MDCKaMDCK-SIAT1aEggsbMDCK-SIAT1/MDCKcEgg/MDCKd
RG WT7.0 ± 0.26.4 ± 0.34.6 ± 0.20.23.6 × 10−3
RG E119V-NA7.4 ± 0.27.1 ± 0.24.8 ± 0.20.52.5 × 10−3
RG R292K-NA6.8 ± 0.44.4 ± 0.2 (6.7 ± 0.3)e<f4 × 10−3<1.6 × 10−7
  • a Mean log10 TCID50/ml ± SD from three independent determinations.

  • b Mean log10 EID50/ml ± SD from three independent determinations.

  • c Ratio of mean TCID50/ml in MDCK-SIAT1 and MDCK cells.

  • d Ratio of the mean EID50/ml and the TCID50/ml in MDCK cells.

  • e Values obtained with the addition of 2 mU/ml C. perfringens NA to the infection medium.

  • f <, below level of detection (<0.75 log10 EID50/ml).