Figure 1. Plaque phenotypes of wild-type, PB2 627E and PB2 627E 701N viruses at 33°C and 37°C.

Plaque assays were performed on MDCK cells incubated at 33°C or 37°C, as indicated at the left of the figure, and immunostained with virus-specific antibody. (A) Plaque phenotypes of rPan99 WT and PB2 mutant viruses. (B) Average plaque diameter for each rPan99 virus is plotted at 33°C and 37°C. (C) Plaque phenotypes of rVN1203 WT and PB2 mutant viruses. (D) Average plaque diameter for each rVN1203 virus is plotted at 33°C and 37°C. Plaque assays of rPan99 viruses and rVN1203 viruses were performed at different times. Error bars indicate standard deviation. * indicates p<0.01 and ** indicates p<0.001, as determined by t-test of plaque diameter values.