Fig. 3: evACE2 in patient plasma neutralizes SARS-CoV-2.

a Schematic depiction of plasma EV ultracentrifugation and RBD-bead based depletion. b Cryo-EM images of human EV pellets isolated from acute phase COVID-19 plasma (bar = 100 nm). c Immunoblots of plasma EV pellets (sero-negative and COVID-19 acute phase patients CBB-005 and -013) for ACE2 and loading control of protein staining with Ponceau). Laemmli buffer was used for lysis (N = 1 experiment). d ACE2⁺ EV pellets from acute phase patients 007, 008, 009, 012, and 013 (CBB) (n = 2 biological replicates each) blocked SARS-CoV-2 infection-induced death of Vero-6 cells whereas the sero-negative control (n = 2 biological replicates) and CBB-005 (no detectable ACE2) (n = 2 biological replicates) did not show neutralization effects. One-tail t test, ****p = 2.24E−08 shown as compared to sero-negative. e, f Levels of ACE2⁺ EV counts (n = 3 biological replicates) in plasma EVs (green) and bead-depleted EVs (light blue). One-tail paired t test, *p = 0.011 and **p = 0.0063 (data are presented as mean values ± SD) (e) and altered neutralization effects on RBD–host cell binding (f) of the COVID-19 plasma EV pellets prior to and after RBD-bead depletion (convalescent phase CSB-012 and -024; acute phase CBB-008, 009, and 013). One-tail paired t test ****p = 5.11E−05.