Multistep growth kinetics assays of indicated recombinant viruses. (A) Virus replication level curve in total samples. (B) Virus replication level curve in the supernatant medium. (C) Virus replication level curve in cell samples. (D to F) Statistical analysis of the difference of virus titer in the total (D), supernatant (E), and cell (F) at each time point. Asterisks indicate significant differences from the WT virus. Data are shown as mean virus titer of three independent experiments each with standard deviations (***, P < 0.001; **, P < 0.01; *, P < 0.05).