At infection the cell monolayers were washed with Dulbecco's PBS to decrease the level of any contaminating BSA from the FBS. Serum-free DMEM was added to the cells as a maintenance medium throughout the virus production phase. Cultures were infected with a working seed preparation of DISC-HSV at a multiplicity of infection (MOI) of 0.01 pfu cell −1 . The temperature of the cultures during the virus production phase was decreased and maintained at 34 • C.