Figure 4. Immunization with NE + rF-ptn or NE + RSV increased viral clearance, promoted a balanced Th1/Th2 cytokine response after RSV challenge, and NE + rF-ptn did not induce airway hyperreactivity. Mice were immunized at weeks 0 and 4 with NE + rF-ptn (2.5 μg rF-ptn) or NE + RSV (1.3 × 10⁵ pfu). Mice were challenged with RSV Line 19 (10⁵ pfu) at week 6 and viral clearance was assessed at day 8 post-infection by real-time Taqman PCR of viral genes in lung tissue. Mucus production was determined by PAS staining of lung sections and scored as described in the methods section. NE + rF-ptn vaccine did not lead to increased inflammation, eosinophilia, mucus or goblet cell infiltration following RSV challenge as compared with sham vaccinated mice that were also challenged with the RSV (B and C). Cytokine mRNA levels from lung homogenates were assessed at day 8 post-challenge. Mice vaccinated with either NE + rF-ptn or NE + RSV showed increased levels of IL-17 mRNA production. There were no significant differences in production of any other cytokine (IL-4, -5, and -13) (D). Mice were vaccinated with NE + rF-ptn (2.5µg rF-ptn) or NE + RSV (1.3x10⁵ pfu) at weeks 0 and 4. Mice were challenged with RSV Line 19 (10⁵ pfu) at week 6 and airway hyperreactivity was assessed via invasive plethysmography at day 8 post-challenge (D). There was no difference in AHR between vaccinated mice and Sham group. (*P < 0.05, **P < 0.01).