At 12 days post-infection we determined the viability of cells collected and cultured at six days post-infection. PI staining of S11 cells, after six days in culture, revealed that 51.7% (62.5 SEM) of cells were PI negative and thus viable. PI staining of post-infection fibroblasts, treated in parallel with infected endothelial cells, revealed that only 14.5% (61.5 SEM) of the cells harvested remained intact. In contrast, PI staining of post-infection endothelial cells revealed that 92.5% (60.3 SEM) of the cells harvested were intact and viable (Fig. 2D) . Analysis of the viral replication program in MB114 endothelial cells at 12 days postinfection revealed that the majority of cells continued to express gp150 (Fig. 3C) . Therefore, infection of endothelial cells with cHV68 resulted in a population of cells that escaped lysis and remained intact as far as 12 days post-infection, while undergoing the lytic transcription program.