In this study we analysed the potential of highly purified polyclonal TcR alpha-beta+, TcR gamma-delta+ and CD3-NK cells, to produce lymphokines in response to mitogenic stimulation. RNA hybridizations were performed to detect with high sensitivity the induction of multiple lymphokine genes. Upon stimulation with lectin and phorbol ester TcR gamma-delta+ lymphocytes expressed the same set of lymphokine genes as the TcR alpha-beta+ lymphocytes, which included IL-2, -3, -4, -5, GM-CSF, TNF-alpha and beta, IFN-gamma. In contrast, a more limited set of lymphokine genes (GM-CSF, TNF-alpha and beta, IFN-gamma) was induced in activated CD3- NK cells, thus indicating that this subpopulation of cells may display different regulatory functions, with respect to CD3+ T lymphocytes.