Fig. 4
Protective efficacy against infections with homologous and heterologous IAV strains. BALB/c mice were immunized as described before and infected with 104 PFU of either PR8 (a, b) or pH1N1 (c–f) on day 52. a, c Weight loss was monitored daily. b For the PR8 infection, four mice of each group were killed on day 3 and day 8 post-infection and viral loads in the BALF were analyzed by qRT-PCR. Naive animals were killed and analyzed already at day 7, because they reached the end-point criteria. The dashed line marks the detection limit (3300 copies/ml). d For the pH1N1 challenge, mice were killed 8 days post-infection and viral RNA copy numbers were quantified in the BALF. e The total amount of protein was determined in BALF of pH1N1-infected mice as a surrogate for tissue damage. f The cellular fraction of the BALF of pH1N1-infected mice was analyzed via multicolor flow cytometry. Absolute cell counts (left) and the relative contributions of the respective cell type within the CD45+ compartment (right) are presented. alv. alveolar, infl. inflammatory. g Secreted IL-1β was determined in BALF at the indicated time points after the vaccination. Day zero indicates values of a naive group of mice. h, i Mice received solely 1 × 109 particles of rAd-IL-1β and were then infected with 104 PFU pH1N1 on day 52. Weight loss and viral RNA was analyzed as described above. Data represent three to eight mice and show the mean with SEM (a, c, e, f right, g), median with interquartile range (f left) or values of individual mice with the median of the group (b, d, i). #p < 0.05 vs. naive; * or the respective group sign, p < 0.05 vs. HA/NP + empty (data of b and d were log-transformed before analysis, one-way ANOVA, Tukey’s post test)
