Figure 6. H1N1 virus challenge. Mice (n = 8) were vaccinated once, or twice 14 d apart, with 15 µg equivalent of HA protein, as free HA or TMV-HA, with and without squalene adjuvant, compared with a commercial H1N1 vaccine or PBS controls. On day 28, immunized mice were challenge with mouse adapted H1N1 influenza A/California/04/09 virus. (A) ELISA (shaded bars, left Y axis) and HAI analysis (open and closed bars, right Y axis) were performed on the sera drawn at day 26 post vaccination. (B) Weight change in each group of mice is represented as percent deviation from original weight. (C) Survival was recorded and plotted as a Kaplan-Meier curve, and groups with significant differences in survival by log-rank analysis against the H1N1 vaccine control are shown. Symbols, as indicated in C, are the same in B.