CTSL and infection: We found that the depletion of CTSL completely aborted the infection of pseudotyped SARS-CoV-2 S/HIV-1 viruses in CTSL+/TMPRSS2– HEK293T-hACE2high cells, whereas the depletion of TMPRSS2 did not abort the infection of pseudotyped SARS-CoV-2 S/HIV-1 viruses in the same cell line (Supplementary Figure 1A).