Approximately 64-68 h post infection cell monolayers have between 90-100% CPE. This observed level of CPE is ideal for harvesting the DISC-HSV. The harvest method involved pouring off the medium and adding 10 ml of hypotonic saline. The cultures were then incubated at 34 • C for 5-10 min. The cells and virus were collected by scraping the surface with a plastic scraper.