CYTOTOXICITY OF NATURAL-KILLER-CELLS AGAI NST PRIMARY AUTOLOGOUS UROTHELIAL TUMOR-CELLS

In previous studies we were able to show that bladder carcinoma cell l ines are in vitro resistant against natural killer (NK) cell activity. After stimulation of the mononuclear effector-cells with interlaukin- 2 (IL-2) or BCG an efficient cytotoxicity against bladder carcinoma ce ll lines could be demonstrated. The aim of the present study was to sh ow, if also carcinoma cells of primary bladder tumors are NK-resistant or if this is only an in vitro phenomenon of the tumor cell lines. We were able to show in a L-[H-3]-methionine-cytotoxicity-assay that eve n short time cultured cells of primary bladder tumors are resistant ag ainst autologous and allogenic NK-cells, but are also sensitive agains t lymphokine-activated killer (LAK) cells and BCG-actiated killer (BAK ) cells. Furthermore we found, that NK-cells of healthy donors and of our patients did not differ in their cytotoxic potential against cells of primary bladder tumors and bladder carcinoma cell lines. We conclu de that these data show the relevance of our in vitro findings for the in vivo situation and prove the importance of stimulation for the kil ling of tumor cells in vivo.