Fig. 1

Inhibition of SARS-CoV-2 and specific targeting of Spike-expressing cells by VSVΔG-ACE2 pseudo-particles. a Schematic representation of a VSVΔG-ACE2 particle, selectively infecting SARS-CoV-2 Spike⁺ cells, while blocking Spike-mediated infection of pseudo-typed and wt virus. b Exemplary immunoblots of whole cells lysates (WCLs) and VSVpp containing supernatants of HEK293T cells transfected with vectors expressing the SARS-CoV-2 Spike or ACE2 proteins and infected with VSVΔG-GFP. Blots were stained with anti-ACE2, anti-Spike, anti-ß-actin, and anti-VSV-M antibodies. c, Infection kinetics of Spike⁺ HEK293T cells inoculated with the indicated volumes of VSVΔG-ACE2. Infected GFP⁺ cells were automatically quantified over a period of 20 h (upper panel). Binary images of HEK293T cells transduced with VSVΔG-ACE2, transfected with SARS-CoV-2 Spike, or both (lower panel). Infection events (i.e. GFP+ cells) are displayed as black dots. d Exemplary gating to detect Spike expressing and VSVΔG infected HEK293T cells (left panel). FACS analysis of Spike expressing HEK293T cells infected with increasing amounts of VSVΔG-ACE2 (right panel). Shown are the percentages of VSVΔG-ACE2 infected cells in the total, Spike-negative and Spike-positive cell population. e Infection of Caco-2 cells with VSVΔG-GFP pseudotyped with the indicated coronavirus Spike proteins. Spike-carrying VSVpp were pre-treated (30 min, 37 °C) with VSVΔG-ACE2 in the ratios 1:3, 1:2 and 1:1 to 1:10⁻⁷ in 10-fold dilution steps. f Inhibition of genuine SARS-CoV-2 strains by VSVΔG-ACE2. Caco-2 cells were inoculated with SARS-CoV-2 NL-02-2020, Delta and Omicron (MOI 0.05) variants pre-treated with VSVΔG-ACE2 at the ratios 1:3, 1:2, 1:1 and 1:0.1. Two days after infection, the cells were harvested, stained with anti-Spike Ab and analysed by FACS. g Infectious SARS-CoV-2 particles in the supernatants of Caco-2 cells infected with mock or VSVΔG(ACE2)pp-treated SARS-CoV-2. The samples correspond to the cultures treated with naked control VSVΔG particles or the highest concentration of VSVΔG(ACE2)pp treated cultures shown in panel f. TCID₅₀ was determined by infection of Caco-2 cells as described in the methods section. b.d.l, below detection limit. (n = 3, ± SEM; p-values were determined using a two-tailed Student’s t test with Welch’s correction. h, Relative body weights of Syrian gold hamsters following infection with SARS-CoV-2 Delta and administration of control or VSVΔG-ACE2. i, Viral RNA loads in nasal and bronchoalveolar lavages (NAL and BAL) of control or VSVΔG-ACE2 treated hamsters three days post-infection with the SARS-CoV-2 Delta variant. j, Lung histology of SARS-CoV-2 delta infected Syrian gold hamsters treated with control or VSVΔG-ACE2. SARS-CoV-2 Spike (red) and hematoxylin (blue) (left panel) and quantification of the corresponding Spike expression (right panel). k Fluorescence immunohistology of the lung of SARS-CoV-2 Delta infected Syrian gold hamsters treated with control (left panel) or VSVΔG-ACE2 (right panel) and stained for Spike and VSV M protein expression