FIG. 6.

T-cell responses in lungs upon challenge. Four-day-old BALB/c mice were infected i.n. with 8 × 10⁴ FFU of RSV/wt, RSV/IFN-γ, or RSV/IL-4. The mice were challenged with 10⁶ FFU of wild-type RSV A2 i.n. at 8 weeks of age. (A to D) Lung CD4 T-cell numbers (A) and activation (B) and the intracellular expression levels of IFN-γ (C) and IL-4 (D) were measured on days 4 and 7 postinfection. (E to I) Lung CD8 T-cell numbers (E), activation (F), M2 specificity (G), and intracellular IFN-γ expression following stimulation (H) and NK cell numbers (I) were measured at the same time points. Data are representative of two repeats, and points represent data for five mice per group ± SEM. *, P < 0.05; **, P < 0.01.