Identification and blockade of cilia-to-goblet cell transdifferentiation in vitro and in vivo. (A) Representative photomicrographs of airway sections obtained from mice at 21 days after SeV inoculation and subjected to confocal immunofluorescence microscopy for β-tubulin (green) and MUC5AC (red). Arrows indicate ciliated cells staining for β-tubulin (ci), goblet cells staining for MUC5AC (g), and cells staining for both β-tubulin and MUC5AC (cig). (B) Representative photomicrographs of airway sections obtained as in A but immunostained for p-EGFR (red) and MUC5AC (green). Arrows indicate ciliated cells staining for p-EGFR (ci), goblet cells staining for MUC5AC (g), and cells staining for both p-EGFR and MUC5AC (cig). (C) Representative photomicrographs of airway sections obtained as in A but immunostained for CCSP (green) and MUC5AC (red). Arrows indicate cells staining for CCSP (cc) or CCSP and MUC5AC (ccg). Scale bars: 20 μm. (D) Quantitative analysis of MUC5AC-expressing cells that also immunostained for CCSP or β-tubulin. (E) Real-time PCR analysis of lung IL-13, mCLCA3, and MUC5AC mRNA levels corrected for GAPDH control level at indicated times after SeV inoculation. (F) Quantitative analysis of β-tubulin, CCSP, and Muc5AC immunostaining in mice inoculated with SeV and treated with sIL-13Rα2-Fc or control IgG on days 12, 14, 17, and 20 after inoculation. Values represent mean ± SEM *Significant difference from corresponding SeV-UV control for D and E or IgG treatment for F.