ANALYSIS OF DIFFERENTIATION EVENTS CAUSING CHANGES IN NK CELL TUMOR-TARGET SENSITIVITY

Publisher Summary This chapter analyzes differentiation events causing changes in natural killer (NK) cell tumor–target sensitivity. The chapter presents data obtained in the analysis of freshly isolated human chronic lymphocytic leukemia (CCL) cells and a murine myeloid leukemia cell line undergoing induced controlled differentiation in vitro . The study described in the chapter analyzed the way in which the induction to differentiation altered the NK sensitivity of the tumor cell population and its ability to be lysed by homologous or xenogeneic effector cells and whether the alteration in sensitivity affected the competing capacity of such cells when known NK target cells were used. Freshly obtained tumor cells from B-CLL patients can, in certain cases, be induced to differentiate in vitro , if treated with the phorbol ester 12-0-tetradecanoyl-13-phorbolacetate (TPA). The total material included 18 B-CLL patients tested at 35 different occasions during a time period of 18 months. A substantial increase in NK cell susceptibility was noted in 19 cases (responders). This increase peaked at the third day of culture. No change in background sensitivity was shown by the cells cultured in the absence of TPA.