Cytokine responses in VLP-vaccinated mouse lungs after RSV infection. (A) The cytokines for the Th1-mediated response are IFN-γ, IL-12p40, and TNF-α. (B) The Th2-mediated response cytokine measurement includes IL-4, IL-5, and IL-13. (C) The IL-17 and IL-1β analysis indicates the Th17-mediated response. (D) The IL-10 cytokine analysis demonstrates immunoregulatory process development. The results were generated using a group of 4 mice for each condition at 4 days postinfection. An asterisk indicates a statistically significant difference between the experimental condition and the placebo control; differences between the FI-RSV and VLP vaccines were statistically significant (P < 0.05) in all groups, with the exception of the prefusion group in the IFN-γ assay. ND, not detectable.