Degenerated PCFs reduced number of cells counted in BALF and infiltrating inflammatory cells at peribronchial and perivascular regions and ameliorated airway resistance after RSV infection. (A) By day 21 of virus infection, the total number of cells, macrophages, and lymphocytes was reduced in PCF-degenerated mice infected with RSV (KPCF-RSV) compared to that of intact mice infected with RSV (RSV). (B) Inflammatory cells infiltrating around the bronchioles were decreased in PCF-degenerated mice with RSV infection (magnification, ×200). (a) Control; (b) RSV; (c) KPCF control; (d) KPCF-RSV. (C) Degenerated PCFs depressed airway responses to aerosol methacholine according to double-chamber plethysmography. Results are representative of two independent experiments, with a total of 5 to 7 mice/group, and all data are presented as means ± SEM. P < 0.01 (**) and P < 0.001 (***) compared to the control group; P < 0.01 (##) and P < 0.001 (###) compared to the RSV group; P < 0.05 (^) and P < 0.001 (^^^) compared to the KPCF control group. Tc, total cells; Mac, macrophages; Lym, lymphocytes; Neu, neutrophils.