FIG 1.

Levels of growth of wtMeV-Luc and wtMeV-eGFP are similar in Vero, Vero.hSLAM, and Vero.hPVRL4 cells. (A) wtMeV-Luc was engineered from the wtMeV-eGFP genome by replacing the transcription unit encoding eGFP located upstream of the MeV H ORF with the firefly luciferase (Luc) ORF. (B) Vero cell lines were infected with wtMeV-Luc and wtMeV-eGFP at an MOI of 0.01. The replication of recombinant viruses was monitored by using fluorescence and phase-contrast microscopy on the indicated days postinfection. Syncytia are delimited (black lines) in the phase-contrast image. (C) At 1 and 2 days postinfection, cell-associated virus titers were quantified and expressed as TCID₅₀ per milliliter. (D) Vero.hSLAM and Vero.hPVRL4 cells were infected with wtMeV-Luc at an MOI of 1. At 4 and 8 hpi, luciferase activity was measured and is displayed as fold induction relative to the luciferase activity measured at 4 hpi. The means of data from three independent experiments are shown, and error bars indicate standard deviations. The asterisks indicate a statistically significant difference (P < 0.05 by ANOVA) in comparisons of data from day 1 and day 2, as well as 4 and 8 hpi, for each virus.