Potent Antiviral Activities of Type I Interferons to SARS-CoV-2 Infection

Emily K. Mantlo; Natalya Bukreyeva; Junki Maruyama; Slobodan Paessler; Cheng Huang

Additionally, virus infection caused strong cytopathic effect (CPE), which was evident at 48 hpi, much later than 05 the peak of virus production (at 40 hpi). The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.04.02.022764 doi: bioRxiv preprint returned, and cells were incubated for a further 22 hours. Supernatants were then collected, and viral titers 11 were determined via TCID50 assay. The result indicated that IFN- treatment potently inhibited SARS-CoV-2 12 infection. Virus titers were not detectable except at the lowest concentration tested (50 IU/ml), at which the viral 13 titers were drastically reduced by 4 logs of magnitude (Fig. 2) . For IFN-β, the virus titers were below the 14 detection limit at all concentrations tested (50 u/ml-1000u/ml), indicating more potent anti-SARS-CoV-2 activity 15 than IFN-α. Consistently, no CPE was observable under microscopic examination in all IFN-treated samples.