Human Angiotensin converting enzyme 2 (ACE2) is a membrane protein found on the surface of cells in the lungs, arteries, heart, kidney, and intestines. ACE2 is the entry point for COVID-19 (SARS-CoV-2) due to its interaction with the coronavirus Spike protein. ACE2 lentivirus expresses human ACE2 under the control of the CMV promoter, with puromycin as a selection marker.