FIG. 4.

NDV-F-treated mice were protected against RSV challenge. Four weeks after mock immunization or immunization with the NDV vector or NDV-F, WT (A) and IFNAR^−/− (B) mice were challenged with 10⁷ PFU of RSV A2 and lung virus titers were determined 5 days later by plaque assay. An asterisk denotes a significant difference between the control-immunized mice (mock and NDV) and the NDV-F-treated mice (P = 0.05 for WT mice; P = 0.025 for IFNAR^−/− mice). Data in panel A were replicated in two additional experiments.