[Phorbol ester-induced expression of primate retroviruses (author's transl)].

Addition of the tumor promoter 12-0-Tetradecanoyl-phorbol-13-acetate (TPA) to the growth medium of certain human cell cultures persistently infected with simian retroviruses of type C (BaEV, SSV) or type D (MPMV) or a human cell line-derived type D isolate (PMFV), respectively, resulted in a considerable but transient stimulation of virus production. Enhanced virus expression was paralleled by striking morphological alterations of the cells. Among four infected cell types tested so far, ony one (A 204) failed to respond to TPA with significant virus stimulation or altered morphology.