B. A549 cells were infected with ZIKV (MOI=3) for 6 hrs prior to addition of IFN-α (100 U/mL), IFN-λ (200 ng/mL) or IFN-γ (10 U/mL) for 12 hrs. Total RNA was isolated and levels of ifit1 RNAs were determined by qRT-PCR. Values are expressed as mean ± standard error. *P<0.05, **P<0.01 (Student's t-test); N=3 