(A) Knockdown of pro-caspase-1 in THP-1 cells. Cell lysates were prepared from lentiviral vector-transduced THP-1 cell lines, expressing shRNA1, 2, or 3 targeting mRNA of pro-caspase-1, for western blot analyses with pro-caspase-1 antibody to examine the knockout (KD) efficacy. (B) Inhibition of pro-caspase-1 and GSDMD processing in pro-caspase-1 KD cells. Both pro-caspase-1 or scramble shRNA KD cells were infected with 0.1 MOI of ZIKV and cell lysates, prepared at various time points p.i., were subjected to western blot analyses with antibodies for pro-caspase-1, cleaved caspase-1 and GSDMD. (C) Cell viability was assessed in pro-caspase-1 or scramble shRNA KD THP-1 cells infected with or without ZIKV at various MOIs by an MTT assay. (D) Culture medium was sampled at various time points p.i. from pro-caspase-1 or scramble shRNA KD cells infected with or without ZIKV for measurement of secreted IL-1β by ELISA. The experiments were performed in triplicates and the data were shown as mean+SD and analysed by unpaired Students t-test. *P, <0.05; **, P<0.01. ns, no significance.