Induction of Endogenous Type C Virus by Defective Herpes Simplex Virus

Abstract

Herpes simplex virus type 1 (HSV-1), rendered defective by ultraviolet light (UV) irradiation or photodynamic treatment, induced endogenous type C virus from A1-2 cells. Infection of A1-2 cells, a clonal line of sarcoma positive, helper negative (S+H-) cells derived from the Balb/c mouse, with defective HSV-1 resulted in the activation of endogenous xenotropic type C virus, as determined by infectious center assay on permissive normal rat kidney (NRK) indicator cells. The amount of xenotropic virus induced depended on UV dose to HSV-1 or visible light dose to HSV-1 treated with the photosensitizing dye, proflavine sulfate. Certain aspects of activation with UV- irradiated HSV-1 were investigated to further characterize this induction and compare it to other chemical means of endogenous type C virus induction. Cell population growth experiments showed that optimum virus induction occurred when cells were in log phase. Investigation of the effect of metabolic inhibitors on UV- irradiated HSV-1 induction demonstrated a decrease in induction by both hydroxyurea, a DNA synthesis inhibitor, and actinomycin D, an RNA synthesis inhibitor, with actinomycin D having a greater inhibitory effect.