(A) NLRP3+/+ and NLRP3-/- THP-1 cells were incubated with SARS-CoV-2 at an MOI of 1 for 1 h, followed by washing away extracellular viruses and further culture for 3 h. Otherwise, cells were stimulated with 10 μM nigericin for 30 min following pretreatment with 1 μg/ml LPS for 3 h. Cell pellets were collected and immunoblotted with antibodies against the indicated proteins. Treatment with 1 μg/ml LPS for 3 h served as a control. 