Testing of cyclophosphamide and diethylstilbestrol for their ability to enhance virus survival in normal human cells.

A relatively simple assay for determining the capability of chemicals to induce the reactivation of UV-irradiated pseudorabies virus in human embryo cells is presented. Using this assay cyclophosphamide (CP) and diethylstilbestrol (DES) were tested in the presence and in the absence of exogenous metabolizing system. N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was used for comparison. CP increased the survival of UV-irradiated pseudorabies virus exclusively in the presence of exogenous metabolizing system. In the cells pretreated with CP or MNNG the survival of the virus was dependent on time interval between host cell pretreatment and virus infection. No enhancement of virus survival was obtained in the cells pretreated with DES.