FIG. 4.

Type I IFN pretreatment does not inhibit SeV-induced CPE. (A) U937 and (B) A549 cells were pretreated with serial dilutions of IFN-α10 (ranging from 0.78 to 50 U/mL) for 24 h and then UI or infected with either EMCV (MOI 0.5) or SeV (150 or 1.5 HA U/mL) for 72 h. Cell viability was measured via MTT assay (U397) or crystal violet staining (A549). CC: untreated, UI; VC: untreated virus infected. (C) Namalwa cells were pretreated with 100 U/mL of all 12 IFN-α subtypes for 24 h and then infected with either VSV (MOI 0.5) or SeV (150 HA U/mL) for 72 h. Cell viability was measured via MTT assay. Results show cell viability as % of cell control. Cell Control: UI, untreated; virus control: virus infected, untreated. MOI, multiplicity of infection.