Figure 3.

ACE2-containing EVs inhibit pseudotyped SARS-CoV-2 transduction. A) Cartoon depicting pseudotype lentivirus assay. Transduction of ACE2⁺ HEK293FT cells by SARS-CoV-2 Spike pseudotyped virus (Spike-lenti) results in expression of enhanced yellow fluorescent protein (EYFP) as a reporter of viral entry. B) Representative relative frequency histograms of EYFP expression of ACE2⁺ or parental HEK293FT cells after exposure to no virus, mock virus (no surface glycoprotein), or Spike-pseudotyped virus. C) Cartoon depicting pseudotype lentivirus inhibition assay. Effective inhibitors of viral transduction reduce the number of cells expressing EYFP. D) Dose-response curve demonstrating the relationship between EV dose and normalized percentage of cells transduced by Spike-lenti. Curves are normalized to the percent of cells transduced at the lowest EV dose in a particular curve. Symbols repesent the mean of three biological replicates except for the ACE2 negative, HS-EV condition, where the third and fourth dilutions in series (2.7 × 10⁷ particles and 6.6 × 10⁶ particles, respectively) are the mean of two biological replicates. Error bars are standard error of the mean. Data are representative of two independent experiments.