An effector cell population (3610 5 cells/well) was cotransfected with 2 mg each of MeV H and F expression plasmids. To inhibit fusion until the cell overlay, the effector cells are incubated in the presence of 100 mM fusion inhibitory peptide (Bachem). Single transfections of plasmids encoding MeV F served as controls. Target cells (6610 5 cells/well) were transfected with 4 mg of the reporter plasmid encoding firefly luciferase under the control of the T7 promoter. Two hours post-transfection, modified vaccinia virus Ankara expressing T7 polymerase at an MOI of 1.0 PFU/ cell was added to the effector cells. Following incubation for 16 h at 37uC, target cells were detached and overlaid on washed effector cells at a 1:1 ratio and incubated at 37uC in the presence of different JMN3-003 concentrations as indicated. Four hours post-overlay, cells were lysed using Bright Glo lysis buffer (Promega), and the luciferase activity determined in a luminescence counter (PerkinElmer) after addition of Britelite substrate (PerkinElmer). The instrument's arbitrary values were analyzed by subtracting the relative background provided by values of the controls, and these values were normalized against the reference constructs indicated in the figure legends. On average, background values were ,1% of the values obtained for reference constructs. For qualitative assessment, transfected Vero-SLAM cells were photographed 18 hours post-transfection at a magnification of 6200.