Figure 2

244/PR8 given 7 days before infection protects elderly mice from influenza, and these mice are then immune to further challenge. The experiment was set up as in Figure 1. Mice were treated intranasally with 244/PR8 at 7 days and 1 day before infection, and at 1 day after infection (solid arrows, panels a, b). Mice were infected with WSN on day 0 (open arrows). The immune status of survivors is investigated in panels c and d with a high dose WSN challenge. (a, c) show the mean clinical disease assessment, and (b, d) show the percentage weight change. Other information as in Figure 1. In panels a, b: ■, 12 μg 244/PR8 given 7 days before WSN (n = 5); □, 12 μg inactivated 244/PR8 given 7 days before WSN (n = 5); ◆, 12 μg 244/PR8 given 1 day after WSN (n = 5); ◊, 12 μg inactivated 244/PR8 given 1 day after WSN (n = 5); ▲, WSN only (n = 5); ●, 244/PR8 only (n = 2). In panels c, d: ■, 12 μg 244/PR8 given 7 days before WSN from (a, b) and rechallenged with WSN (n = 4); —, 12 μg 244/PR8 given 1 day before WSN from (a, b) (not shown) and rechallenged with WSN (n = 5); ●, saline inoculated controls only from (a, b) (not shown) challenged with WSN (n = 2); ○, non-infected controls (n = 2). The dagger in panels (b) and (c) indicates the death of a single mouse.