INCORPORATION OF STILBAZOLIUM MEROCYANINES INTO HUMAN-LEUKOCYTES MEASURED BY FLOW-CYTOMETRY

Human peripheral blood leukocytes were incubated with thirteen various merocyanines of the stilbazolium betaine type and the fluorescence in tensities of the cells were measured by flow cytometry. The fluorescen ce intensity of lymphocytes, monocytes and granulocytes depended on th e time and temperature of incubation with the dyes. An increase in the incubation temperature enhanced the fluorescence intensity whereas wa shing of the cells after incubation had little influence on the observ ed emission. This points to incorporation of the dye molecules into th e cell membrane. From the measured fluorescence intensities corrected for relative fluorescence yields, the relative efficiencies df incorpo ration into the cells of the various merocyanines tested were evaluate d. The efficiency was dependent on the type of the cells and the lengt h and side groups of the merocyanine molecules studied.