Fig. (3) Characterization of recombinant LAIV-RSV/F viruses in BALB/c mice. A. Replication of the LAIV viruses in the upper (nasal turbinates) and lower (lungs) respiratory tract. B. Influenza virus-specific serum IgG antibody responses measured three weeks after the second vaccine dose. The antibody levels are presented as the area under the curve (AUC) of OD450 values for a series of 2-fold serum dilutions. C. Protection of immunized mice against influenza virus challenge measured by the assessment of the challenge viral titers in the lungs three days after infection. Data were analyzed with one-way ANOVA, followed by Tukey's multiple comparisons tests. *p<0.05; ****p<0.0001.