Extended Data Fig. 1: Stains of the lungs in HB-01-infected wild-type and hACE2 mice at 3 and 5 dpi.

a, Modified Masson’s trichrome stain of the lung. Compared to the HB-01-infected wild-type mice, increased collagen fibres (blue-stained fibres) in the thickened alveolar interstitium were observed in the HB-01-infected hACE2 mice at 3 and 5 dpi. Blue frames in the top-right corners are magnifications of the region in the corresponding blue box. b, Periodic acid–Schiff (PAS) stain of the respiratory epithelium in bronchioles. A small amount of mucus accumulated on the surface of bronchial epithelial cells. Red frames in the top-right corners are magnifications of the region in the corresponding red box. Scale bars, 40 μm. Data in a, b are representative of three independent experiments.