A NOVEL-APPROACH TO THE MEASUREMENT OF DIFFERENT IN-VITRO LEUKEMIC-CELL GROWTH-PARAMETERS - THE USE OF PKH GL FLUORESCENT-PROBES

The application of the fluorescent cell membrane probes PKH 2 and PKH 26 GL in the measurement of leukaemic cell growth was examined on four cell lines K562, NALM-6, ACV (a pre-B cell line) and HL-60 using flow cytometry. As the amount of probe per cell reduces at each cell divis ion, the fluorescence can be used to measure cell proliferation. By me asuring the mean fluorescence intensity of the cells at the beginning of culture and at various time points, and by combining this informati on with a viable cell count, it was possible to determine: (1) the num ber of viable cells; (2) their rate of proliferation; (3) their number of cell divisions; and (4) the maintenance of cells in a viable state over a period of time. It was demonstrated that these parameters coul d be reliably established using the red fluorescent probe PKH 26 GL. I n contrast, the green fluorescent probe PKH 2 GL showed dye transfer r esulting in an underestimation of the number of cell divisions and an overestimation of the maintenance of cells in a viable state. The pote ntial advantages of the use of PKH 26 GL over conventional assays for the measurement of leukaemic cell growth parameters are discussed.