To do so, we used two epithelial cell lines derived from human pulmonary adenocarcinomas, Calu-3 and A549-ACE2, which are permissive to SARS-CoV-2 and mimic key features of the human primary pulmonary epithelial cells making them useful for in vitro models of infection (28, 49–52). This evidence concerns the gene ACE2 and infection.