Figure 1

Ex vivo NK proliferation with IL-2 or IL-15 in the presence or absence of IL-21. (a) Proliferation of bulk natural killer (NK) cells. NK cells stained with CFSE (5-carboxyfluorescein diacetate succinimidyl ester) were gated onto the CD3-negative fraction from peripheral blood mononuclear cells and cultured for seven days with IL-2 or IL-15 in the presence or absence of IL-21. The number of cells undergoing division was analyzed at days 5 and 7. Proliferating NK cells are expressed in percentages. This experiment is representative of three individual experiments performed. (b) Proliferation of NK cell subpopulations. NK cells stained with CFSE were purified by magnetic beads, and CD56^dim and CD56^bright subpopulations were isolated by fluorescence-activated cell sorting. The two populations were cultured for 7 days with IL-2 or IL-15 in the presence or absence of IL-21 and analyzed at day 7. The percentage indicates proliferating NK cells. This experiment is representative of three individual experiments performed. (c) Amplification of CD56^dim and CD56^bright subpopulations. Sorted 200,000 CD56^dim and CD56^bright NK cells were plated at day 0 and cultured for 7 days with IL-2 or IL-15 in the presence or absence of IL-21. At day 7 NK cells were stained for their purity (data not shown) and counted. The results are expressed as fold increase as compared to day 0.