Intranasally administered Ad6 is more pathogenic and replicates better in the lung than Ad5. (A) Body weight changes. Mean values ± standard errors of the means (SEM) for each group are shown. Vehicle versus Ad5 at 3.3 × 108, P = 0.2804; vehicle versus Ad5 at 1 × 109, P = 0.0771; vehicle versus Ad5 at 3.3 × 109, P = 0.0017; vehicle versus any Ad6 group and Ad5 groups versus respective Ad6 groups, P < 0.0001 (two-way ANOVA). (B) Virus burdens in lungs. Each symbol represents the value from an individual animal; the horizontal bars signify the mean value for each group. NQ, nonquantifiable.