Figure 3
Mice immunized with rAd-M2 and rAd-NPA survive inhaled, but not instilled, PR8 challenge. Survival of immunized mice is shown for (A) instilled, and (B) inhaled virus challenge. Mice in all groups (n = 10) were challenged on the same day; to more easily visualize differences, naïve, PR8 and X-31-exposed mice are shown in graphs on the left hand side, and groups vaccinated with adenovirus recombinants expressing HA, M2, NPA and NPB are shown graphically on the right hand side. Since 5 mice were sacrificed in each group on day 4, survival of the remaining 5 was monitored to the end of the study (12 days post challenge). A key indicating the color code for each group is provided on the figure. Survival against both instilled or inhaled virus challenge was significantly greater for mice previously infected with either PR8 or X31 than naïve mice (Mantel-Cox test, p < 0.001); similarly survival of mice immunized with Ad-HA was greater than Ad-NPB-immunized mice (control group) when challenged with instilled or inhaled virus challenge (p < 0.001). The difference in survival between Ad-NPB-immunized and Ad-M2 or Ad-NPA-immunized mice was not statistically different when challenged with instilled virus, but trended towards significance (p = 0.054) for mice challenged by inhalation.