Detection of tumor promoters by early antigen expression of EB virus in Raji cells using a fluorescence microplate-reader

As an in vitro assay for possible tumor promoters, we designed a quantitative immunofluorometric method to detect Epstein–Barr virus early antigen (EBV-EA) expression in Raji cells. In this method, anti-EBV-EA monoclonal antibody, a fluorogenic substrate and a fluorescence microtiterplate-reader were employed. 12-O-Tetradecanoylphorbol-13-acetate (TPA) was shown to be a potent inducer. EBV-EA induction by TPA was related to the activation of protein kinase C and phospholipase A2. The chemicals that reacted positively were okadaic acid, diethylstilbestrol, progesterone, sodium phenobarbital, aldrin and dieldrin. Lithocholic acid, testosterone and DDT were equivocal in the present experiments. Eight other chemicals tested did not react.