(D-F) CD14+ monocytes sorted from healthy PBMCs were infected with SARS-CoV-2 viruses at an MOI of 1 for 1 h, followed by washing away extracellular viruses and further culture to meet the indicated infection time. Supernatants were collected and subjected to RT-PCR analysis of viral RNAs (D) and ELISA assay of IL-1β (E). The percentage of cells undergoing cell death was calculated through checking released LDH in the supernatants (F). For D-F, Student's t-test was used and data were shown as means±SD of three technical replicates. ***, P<0.001; results were repeated for three times with similar results. Data information: Student's t-test was used and data were shown as means±SD of three technical replicates. *, P<0.05; **, P<0.01; ***, P<0.001; NS, non-significant. results were repeated for three times with similar results. 