X090930

Lung tissue sections (3 µm) were cut from paraffin-embedded blocks individually. Tissue sections were treated with target retrieval solution (pH6, S169984, Dako, Victoria, Australia) in a Decloaking chamber at 110 °C for 15 min, followed by 3% hydrogen peroxide in water (v/v) (H1009, Sigma-Aldrich, Melbourne, Australia) for 15 min and with protein block solution (serum-free, X090930, Dako, Mulgrave, Australia) for 30 min at ambient temperature before applying the primary antibodies. The sections then were immunohistochemically stained using primary antibodies: ACE2 (1:800 dilution, ab15348, Abcam, Melbourne, Australia), TMPRSS2 (1:250 dilution, bs-6285R, Bioss antibodies, Redfern, Australia), Furin (1:200 dilution, bs-13228R, Bioss antibodies, Redfern, Australia), α-SMA (1:500, M0851, Dako, Mulgrave, Australia) and TGF-β1 (1:2000, ab215715, Abcam, Melbourne, Australia). The tissue slides were incubated in an IHC humidity chamber for 1 h at ambient temperature, followed by peroxidase-conjugated polymer backbone-carried secondary antibodies and visualized by 3,3′-diaminobenzidine (DAB) staining (EnVision™ Detection Systems, Peroxidase/DAB, Dako, Mulgrave, Australia).

We determined SARS-CoV-2 levels at 72 h post infection using SARS-CoV antibody (BEI Resources, NIAID, NIH, NR-10361, 1:400), anti-SARS-CoV S Protein (similar to 240C) (BEI Resources, NIAID, NIH, NR-616, 1:100), and anti-dsRNA (Absolute Antibody, Ab01299-2.0, 1:100). We fixed Vero, HEK293-ACE2, and ALI cells with 4% paraformaldehyde for 15 min and permeabilized with 0.5% Triton X for 10 min. We then blocked for 1 h at room temperature with serum-free protein block (Dako X090930) and incubated with primary antibody overnight. Secondary antibodies were incubated for 1 h, and slides were mounted using Vectashield hardest mounting medium with DAPI (Vector Labs H-1500). We used LSM700 and LSM880 Zeiss confocal microscopes to obtain images. Antibody details are given in Supplementary Table 1.