Induction of epstein‐barr virus by a new tumor promoter, teleocidin, compared to induction by TPA

The effect of teleocidin, a new, naturally occurring tumor promoter, on induction of Epstein‐Barr virus (EBV), was compared with that of a known tumor promoter, 12‐ O ‐tetradecanoyl‐phorbol‐13‐acetate (TPA). Early antigen (EA) and/or capsid antigen (VCA) of EBV was induced in the EBV genome‐carrying cell lines C‐6 and P3HR‐I cells by teleocidin, its effect being maximal at a concentration of 12.5 ng/ml. The production of infectious EBV from P3HR‐I cells was enhanced by teleocidin maximally at a concentration of 0.5 to 2.5 ng/ml. The outgrowth of EBV‐transformed cells from peripheral lymphocytes of seropositive healthy donors was also enhanced by teleocidin at a concentration of 0.02 to 0.5 ng/ml. TPA tested simultaneously in all experiments exhibited the same activities as teleocidin, and was effective at similar concentrations. Teleocidin enhanced both EA and VCA synthesis in P3HR‐I cells additively with n ‐butyrate, but not with TPA. This suggests that teleocidin and TPA have a common mechanism of action, although their chemical structures are different.