Figure 3.

(a) Comparative kinetics of foot-and-mouth disease virus (FMDV) virion antigen detection (4C9 monoclonal antibody) in pulmonary macrophages (Pul-Mφ) (•), BHK-21 cells (○) and SF9 cells (▵). †, cell death. The results are from three independent experiments, expressed as the mean value±SD. (b) Virus RNA synthesis was measured by [³H]uridine incorporation into FMDV-infected cells. FMDV at 10 tissue culture infection dose 50% (TCID₅₀)/cell was added to actinomycin D-treated Pul-Mφ (•) and BHK-21 cells (○), before radiolabelling for the indicated times (x-axis), as described in the Materials and methods. The results are from four replicate experiments, expressed as the mean counts per minute (c.p.m.) minus the background c.p.m. (±SD). (c) Percentage of Pul-Mφ (•) and BHK-21 cells (○) staining with propidium iodide (PI) following interaction with FMDV, as an indication of cell death. Cells were treated with FMDV at 10 TCID₅₀/cell, harvested at the indicated time-points, stained with PI and measured using flow cytometry. The results are from three independent experiments, expressed as the mean±SD.