Figure 1

Lung viral loads and serum neutralizing antibodies in vaccinated young and aged BALB/c mice. Groups of mice (n=14) were vaccinated twice i.m. and sera were collected by submandibular bleeding at day 27. Mice were challenged intranasally with 10⁶ PFU RSV strain A2 at day 28. (A) Viral load. Lungs were harvested 4 days post-challenge, homogenized, and infectious RSV was titrated by plaque assay. *P < 0.05 comparing F to F + alum in young mice (ANOVA). ^#, P < 0.05 comparing F to F + alum in aged mice (ANOVA). Each symbol represents an individual mouse. The dotted line represents the limit of detection. (B) Neutralizing antibody titer. Sera from vaccinated mice were tested for RSV neutralizing activity, *P < 0.05 comparing F to F + alum in young mice (ANOVA). ^#, P < 0.05 comparing F to F + alum in aged mice (ANOVA). **, P < 0.05 comparing F in young mice to F in aged mice (ANOVA). ^##, P < 0.05 comparing F + alum in young mice to F + alum in aged mice (ANOVA). The dotted line represents the limit of detection. (C) Body weight. Groups of mice (n=14) were unvaccinated or vaccinated twice i.m. and challenged intranasally with 10⁶ PFU RSV strain A2 at day 28. Body weights were recorded daily for 4 days. Data are combined from two independent experiments.