PROS1 and COVID-19: Primary cultures of human lung epithelial cells were treated with S Protein (recombinant S protein of SARS-CoV-2, the agent of COVID-19, 1 μg/mL) or 229E (hCoV-229E, the common cold virus, 0.1 MOI or recombinant S protein, 1–5 μg/mL) to determine the Ethidium uptake rate (Etd, 5 μM), by live-cell imaging, as a measure of Panx-1 channel opening.