Biosciences

On days 0, 1, 3, and 5 postinfection “Arlo” cells were lysed for Western blot analysis using Triton‐X‐100 sample buffer, as described previously.^[130] Proteins were separated by SDS‐PAGE. Specific antibodies against SARS‐CoV‐2 N (1:1000 dilution, SARS‐CoV‐2 Nucleocapsid Antibody, Rabbit monoclonal antibody (Mab), #40143‐R019, Sino Biological), ACE2 (1:500 dilution, Anti‐ACE2 antibody, #ab15348, Abcam), TMPRSS2 (1:1000 dilution, Recombinant Anti‐TMPRSS2 antibody [EPR3861], #ab92323, Abcam), and GAPDH (1:1000 dilution, Anti‐G3PDH Human Polyclonal Antibody, #2275‐PC‐100, Trevigen) allowed antigen detection. Protein bands were made visible by laser‐induced fluorescence using an infrared scanner for protein quantification (Odyssey, Li‐Cor Biosciences).

Cells were lysed using Triton-X-100 sample buffer (Sigma-Aldrich), and proteins were separated by SDS-PAGE. Detection occurred by using specific antibodies against SARS-CoV-2 N (1:1000 dilution, SARS-CoV-2 Nucleocapsid Antibody, Rabbit monoclonal antibody (Mab), #40143-R019, Sino Biological), ACE2 (1:500 dilution, Anti-ACE2 antibody, #ab15348, Abcam, Berlin, Germany), TMPRSS2 (1:1000 dilution, Recombinant Anti-TMPRSS2 antibody [EPR3861], #ab92323, Abcam), and GAPDH (1:1000 dilution, Anti-G3PDH Human Polyclonal Antibody, #2275-PC-100, Trevigen, Wiesbaden, Germany). Protein bands were visualized by laser-induced fluorescence using an infrared scanner for protein quantification (Odyssey, Li-Cor Biosciences, Bad Homburg, Germany).