FIG. 4.
Binding of VP-14637 to RSV-infected cells. Hep-2 cells were infected with RSV or mock infected for 48 h (A) or 28 h (B and C) and incubated with various concentrations of [3H]VP-14637 for various lengths of time. After incubation, the cells were washed, lysed, and counted in a scintillation counter. (A) Specific binding of VP-14637 to RSV-infected cells was determined following the incubation of cells with 10 nM 3H-lableled compound for 150 min. Where indicated, a 1 μM excess of unlabeled compound was added. (B) Specific equilibrium binding was determined by subtracting the signal for mock-infected cells from that for RSV-infected cells. (C) The same data plotted as total binding versus drug concentration illustrate saturation binding for RSV-infected cells. Specific binding was used to calculate the reported Kd values for VP-14637.