FIG. 2.

Determination of FMDV titers after PPMO treatment. (A) Dose response of viral titers in the presence or absence of PPMO. Cells were treated with PPMO or mock treated for 1 h before inoculation with A₂₄Cru at 0.5 PFU/cell in serum-free media. Following 24 h of incubation under further PPMO treatment, the virus yield was determined by plaque assay and expressed as PFU/ml. Each histogram presents the mean PFU/ml of four samples, and the corresponding standard deviations are shown as error bars. The data from one representative experiment are shown. (B) Uninfected BHK-21 cells were treated with the indicated PPMO at various concentrations under the same experimental conditions as for panel A. Values are presented as percentages of viable cells compared to that of the mock-treated controls, with corresponding standard deviations. (C) Twenty-four hour one-step growth curves of FMDV A₂₄Cru from cells subjected to treatment with a 5 μM concentration of the indicated PPMO. Cell monolayers were mock- or PPMO-treated and infected with A₂₄Cru at a MOI of 5 PFU/cell. The procedures used for PPMO treatment, viral infection, and titration of infectivity are described in Materials and Methods. Each value represents the mean of duplicate assays.