FIG 6.
X31-sciIV provides protection from heterologous influenza virus challenge. Female C57BL/6 mice were primed with either 105 PFU of X31-sciIV virus, 105 PFU of WT X31 virus, or PBS control and rested for 14 days before challenge with a lethal dose of PR8 virus. Animal body weight loss (A) and survival (B) in each group (n = 10) were monitored daily for 2 weeks after challenge. (C) Weight loss after a nonlethal PR8 challenge. Female C57BL/6 mice were primed with either 105 PFU of X31-sciIV, WT X31 virus or PBS control and rested for 14 days and then rechallenged with a nonlethal dose of PR8 virus. Weight loss of the animals in each group (n = 10) was then monitored daily for 2 weeks. The data presented are averages ± the SD and are representative of two independent experiments.