2.4 Cells and viruses
H1299 cells were obtained from the Korean Cell Line Bank (KCLB, South
Korea, 25803) and cultured in RPMI-1640 (Gibco, USA). HEK293T and Vero
cells were obtained from the American Type Culture Collection (CRL-3216
and CCL-81) and cultured in Dulbecco’s Modified Eagle’s Medium (DMEM;
Corning, USA), respectively. Both culture media were supplemented with
10% fetal bovine serum (FBS) (Gibco, USA) and 1X
Penicillin-Streptomycin solution (HyClone, USA). Cell cultures were
incubated at 37°C in a humidified incubator containing 5% CO2. For
viruses, early isolates of SARS-CoV-2 viruses (NCCP43326) and four
SARS-CoV-2 variants including Alpha (NCCP43381), Beta (NCCP43382), Delta
(NCCP43390), and Omicron (NCCP43408) were obtained from Korea Disease
Control and Prevention Agency (KDCA). These viruses were propagated in
Vero E6 cells and the viral titers were determined by plaque assay using
Vero cells. All experiments with these viruses were conducted in an
enhanced biosafety level 3 (BSL‐3) containment facility at Institut
Pasteur Korea as approved by the KDCA.