Suppression of type I IFN signaling by HRTV infection.
A, HRTV infection inhibits IFN-α–driven activation of the ISRE promoter. HEK293 cells were cotransfected with an ISRE reporter plasmid and an internal control plasmid (pRL-TK). At 12 h posttransfection, cells were mock-infected or infected with HRTV (MOI = 5) or SFTSV (MOI = 5), respectively. At 24 hpi, cells were left untreated or treated with IFN-α (1000 units/ml) for 18 h, followed by the measurement of luciferase activities. Relative luciferase activity (Rel. Luc. Act.) and -fold activation of ISRE are shown, respectively. B, HRTV infection blocks IFN-α–induced ISG expression. HEK293 cells were mock-infected or infected with HRTV (MOI = 5) or SFTSV (MOI = 5). At 24 hpi, cells were left untreated or treated with IFN-α (1000 units/ml) for 10 h, followed by the detection of ISG mRNA expression by real-time qPCR. Graphs show mean ± S.D. (error bars) (n = 3).