Effect of selected DHODH inhibitors on LCMV multiplication. A549 cells were infected (MOI = 0.01) with rCL-13/ZsG in the presence of the indicated DHODH inhibitors (5 µM) or dimethylsulfoxide (DMSO) vehicle control (VC). (A) At the indicated hour (h) post-infection (pi), numbers of ZsG-positive cells were determined by epifluorescence. (B) At the indicated time point, total cellular RNA was purified and equal amounts (1 µg) were used in reverse transcription reactions, using random hexamer primers to generate complementary DNAs (cDNAs) that were used in polymerase chain reactions (PCRs) with specific primers to amplify a segment of 644 bp of the viral nucleoprotein (NP) gene. PCR products were resolved by agarose gel electrophoresis and visualized by ethidium bromide staining. (C) At the indicated h pi, tissue culture supernatants were harvested, and virus titers were determined. Values for VC-treated samples correspond to two replicates. Error bars represent mean +/− standard error of the mean (SEM). The number below each band indicates the normalized fold change on band intensity compared to mock-infected and vehicle-treated control cells.