Fig. 5: Influence of rAd19a boost immunization on protective efficacy against RSV.

BALB/c mice were primed intramuscularly with an F-encoding DNA plasmid (10 µg plasmid) followed by electroporation and boosted 28 days later intranasally (i.n.) or intramuscularly (i.m.) with rAd19a viral vector encoding for F or the influenza nucleoprotein (NP; mock) (2 ×10⁶ infectious units per vector). 37 days after second immunization, all mice were challenged with 5 ×10⁶ PFU RSV-A. a Animals were monitored daily for body weight. Time points show group´s mean values with +SEM; rAd19a-Mock (i.m.) n = 5, other groups n = 6. Data were analysed by Friedman test followed by Dunn´s multiple comparison test. Statistically significant differences were indicated among naive and vaccinated groups; (o: statistically significant worse than naive; +: statistically significant better than naive). b Tissue damage was measured indirectly by protein content in the BALF eight days after infection. Bars represent mean values with +SEM; rAd19a-Mock (i.m.) n = 5, other groups n = 6. Data were analysed by one-way ANOVA followed by Tukey´s multiple comparison test. Statistically significant differences were indicated among all groups (*p < 0.05; **p < 0.005; ***p < 0.0005; ****p < 0.0001). c At day eight, viral loads in BALF samples were measured by qRT-PCR. Depicted are the individual copies/ml BALF with the group´s mean values with ±SEM; rAd19a (i.n.) n = 4, rAd19a-Mock (i.m.) n = 5, other groups n = 6. The qRT-PCR´s detection limit was 667 copies/ml BALF and is marked with a dotted line. Data were analysed by one-way ANOVA followed by Tukey´s multiple comparison test. Statistically significant differences were indicated among all groups. (**p < 0.005; ***p < 0.0005).