PROS1 and viral infectious disease: To test for anti-SARS-CoV-2 activity, we first developed a SARS-CoV-2 pseudovirus (pSARS-CoV-2) that carried the full-length S protein of SARS-CoV-2 on HIV-based lentiviral particles and the luciferase gene as a reporter24 to mimic the S protein of the native SARS-CoV-2 virus and retain its ability to bind to host cell surface receptors for viral infection.