Figure 1.

In vitro replication of cell-culture-adapted H3N2 virus. (A) Schematic representation of recombinant (r) A/Perth/16/2009 wild-type (WT) and mutant virus constructs. MDCK (B,C) and A549 (D,E) cells were infected with rPerth WT (black circles) and HA mutant (red squares) viruses at MOIs of 1.0 or 0.01. Cells were infected in triplicate and supernatants were collected at the indicated times. Virus titers were determined on MDCK cells using TCID₅₀ assays. Graphs are representative of three independent experiments. Two-way ANOVA was used to determine statistical significance (* p < 0.05, ** p < 0.005, *** p < 0.0005). The dashed line denotes the limit of detection for the titration assay.