Fig. 2.

Immune protection from lethal H1N1 challenge in mice. Mice (n = 15) were immunized with Ad5 [E1-, E2b-]-HA + NA (2 × 10¹⁰ VP total) once (●), twice (■) or three times (▲) at a two week interval. A fourth group of mice were immunized three times at a two week interval with 10¹⁰ VP of Ad5 [E1-, E2b-]-HA alone (▼). Mice immunized with Ad5-null, an Ad5 vector with no transgene insert, were used as a vector control group (○) and non-immunized mice were used as experimental controls (◆). Forty-six days after the last vaccination, mice were inoculated intranasally with 10⁵ PFU/animal of Influenza H1N1 A/CA/07/2009 and weight loss (a) and survival (b) were recorded and evaluated. p < 0.01; log rank test between vaccinated and vector control mice survival and p < 0.01; log rank test, between vaccinated and experimental control mice survival by Mantel–Cox analysis.