IBV infects ciliated cells and goblet cells, but not basal cells. At 48 h.p.i. with IBV, double staining for IBV proteins and β-tubulin (A, E), mucin5AC (B, F) or K14 (C, G) was performed in cryo-sectioned tracheal tissues (A–D) and ATE cells (E–H). Panels (D) and (H) are higher magnifications of panels (C) and (G), respectively. Scar bar, 20 μm. (A color version of this figure is available at www.vetres.org.)