FIGURE 5.

Protective efficacy in TLR3^-/- TLR7^-/-BALB/c mice vaccinated with X-31ca after RSV challenge. (A) TLR3/7 knockout (KO) mice (n = 3 per group) or (B) wild-type (WT) mice (n = 3 per group) were vaccinated with 10⁶ PFU of X-31ca and challenged with 10⁶ PFU of RSV A2 2 days later (–2d Vac). Non-vaccinated animals were infected with 10⁶ PFU of RSV A2 only (No Vac). Lung viral titer was determined by plaque assay using lung supernatants obtained from the mice euthanized at day 4 p.c. The dotted line represents the limit of detection; 100 PFU/g of lung tissue (^∗∗P < 0.01 compared with the No Vac control group).