(A–F) Vero cells were pretreated with DMSO (as the control) or the indicated concentrations of 25-HC (A), U18666A (B), or BF738735 (C) for 24 h and then transfected with AiV replicon RNA. At 10 h after transfection, the cells were analyzed for luciferase activity. Data were normalized to the DMSO treatment, and cell viability was scored. (D–F) Vero IFITM1 cells were incubated with or without Tet for 48 h and then treated with mock (–) or 1 μM of 25-HC (D), 1.5 μM of U18666A (E), or 150 nM of BF738735 (F). After 24 h, the cells were transfected with AiV replicon RNA, and luciferase activity was determined at 10 h after transfection. (G) Cell viability was measured in parallel. The maximum value obtained for Tet (–) drug-untreated cells was taken as 100%. Data are the mean ± SD of at least three independent experiments. *, P < 0.05; **, P < 0.001; ***, P < 0.0001.