FIG. 3.

Persistence and viability of infected cells in HeLa cell cultures infected with the BoHV-4 strain V.test EGFP XhoI. HeLa cells were infected with the BoHV-4 V.test EGFP XhoI strain at an MOI of 0.5 PFU/cell. The cells were then passaged every other day (1:2 split ratio). At the indicated times, the percentages of EGFP-expressing cells (A) and cell viability (B) were determined by flow cytometry as described in Materials and Methods. Cell viability was estimated for EGFP-positive and -negative cells. Each value represents the percentage of EGFP-positive cells (A) or viable cells (B) based on an analysis of 10,000 cells.