(A) Representative histologic sections of HAE inoculated with RSV expressing GFP and counterstained with H&E or immunoprobed for GFP (green) and β-tubulin IV (red) at days 1, 3, and 5 pi. Yellow outlines at top left depict the different ciliated cell morphologies seen in RSV-infected HAE, where noninfected ciliated cells are columnar and RSV-infected ciliated cells exhibit rounded morphology. Arrowheads indicate robust apical terminal web in noninfected ciliated cells (top left), which thins in RSV-infected ciliated cells with rounded morphology (top right). Images are representative of independent experiments with 4 different donor cultures. Scale bar: 10 μm. (B) Representative TEM of cross-sections of the apical surfaces of noninfected (left) and RSV-GFP–infected (center, right) HAE. Arrowhead indicates particulates showing virus-like morphology. Asterisk indicates disorganized basal bodies. Scale bars: 1 μm.