SARS-CoV-2 pseudovirus infection for viral entry and titration
To determine viral titer, Vero E6 cells were seeded in a 24-well-plate before the day of infection. 100 µl VSV-ΔG-Spike pseudotyped virus was diluted 3-fold serial dilutions up to 1:243 using DMEM 5% FBS as diluent. After 24 hours, GFP positive cells were counted in the last wells to calculate the TU/ml.
For viral entry assay, medium was replaced with 200 µl cell culture medium including Hydroxychloroquine (20-50 µM) as a SARS-CoV-2 blocker for 20 minutes. Then, treated wells were inoculated with SARS-CoV-2 Spike protein pseudotyped VSV-ΔG (VSV-ΔG-Sdel21). 48 hours of post infection, the plate was scanned with Axio Observer Fluorescence Microscope (Zeiss).