Activation of human NK cells and monocytes with cisplatin in vitro.

Human natural killer (NK) cells and monocytes treated in vitro concomitantly with cisplatin and rIFN-gamma enhanced lysis of K562 cells. Lysis was dependent upon the duration of treatment. Cisplatin and rIFN-gamma treated monocytes were equally cytotoxic to NK sensitive (K562) and NK resistant (Daudi & Raji) cell lines whereas NK cells were not rendered cytotoxic against NK resistant tumor cells. NK- and monocyte-mediated cytotoxicity against K562 cells was further enhanced when the effector cells were primed with rIFN-gamma and were subsequently treated with cisplatin.