ACE2 and COVID-19: Importantly, depletion of ACE2+ EVs isolated from five plasma samples (convalescent CSB-012 and CSB-24, and acute phase CBB-008, 009 and 013) significantly impaired the ability of plasma EVs to neutralize RBD-binding to ACE2+ HEK cells (Fig. 3f), indicating that the ACE2+ EVs in the plasma from COVID-19 patients were at least partially responsible for the anti-SARS-CoV-2 activity.