Figure 4. Therapeutic efficacy of 5A7 in mice.

(A) Mice were treated intraperitoneally with HuMAb 5A7 at 1 (red line), 5 (blue), 10 (green), or 15 (orange) mg/kg or with control IgG at 10 mg/kg (black) 4 hours after intranasal injection of a lethal dose (1.47×10³ MLD₅₀/mouse) of mouse-adapted B/Ibaraki/2/1985. Survival and body weight were checked daily. Each group consists of five mice. Body weight is shown as the mean ± SEM of five mice. (B) Mice were treated with 5A7 (+) or control IgG (D23-1B3B9; −) at 10 mg/kg 4 hours post-infection with 1.47×10³ MLD₅₀/mouse of mouse-adapted B/Ibaraki/2/1985 (left panel) or 5.0×10³ FFU/mouse of B/Florida/4/2006 passaged eight times in mouse lung (right panel). The titers in lungs were calculated at day 3 and day 6 post-infection. Each group consists of five mice (except control IgG-treated group with mouse-adapted B/Ibaraki/2/1985 at day 6, which consists of four mice as one accidentally died before the lung could be collected). Black bars are mean values. **: P<0.01 compared to control IgG-treated group. (C) Two independent experiments were similarly performed (Left two panels). Mice were given 10 mg/kg HuMAb 5A7 at 4 (red line), 24 (blue), 48 (green) or 72 (orange) hours post-infection with mouse-adapted B/Ibaraki/2/1985 (1.47×10³ MLD₅₀/mouse). Right panel shows 10 mg/kg control IgG-treated group at 4, 24, 48 or 72 hours post-infection. Survival and body weight were checked daily. Each group consists of five mice per experiment. Body weight is shown as the mean ± SEM of five mice.