FIG 7.

Inhibition of viral replication and transcription. Human 293T cells (96-well plate format; 5.0 × 10⁴ cells/well; quadruplicates) were transiently transfected with 125 ng of ambisense pDZ plasmids encoding PR8 PB2, PB1, PA, and NP, together with 250 ng of hpPol-I Gluc and hpPol-I GFP vRNA-like expression plasmids and 50 ng of pCAGGS-Cluc. Cells transfected in the absence of pDZ-PB2 were used as a negative control. After 6 h, transfection medium was replaced with medium containing 3-fold serial dilutions of the indicated compounds (starting concentration of 50 μM). At 24 h posttransfection, Gluc and Cluc expression levels were determined from tissue culture supernatants from transfected cells. Transfected cells were also imaged for GFP expression using a fluorescence microscope. Cells treated with 0.1% DMSO vehicle were used as an internal control. The EC₅₀ was calculated as a percentage relative to values obtained with DMSO vehicle-treated cells. Dotted lines indicate 50% inhibition viral replication and transcription. Data are expressed as mean and SD from three independent experiments conducted in quadruplicate. Bar, 50 μm.