Fig. 2

Ex vivo expansion and identification of UCB-NK. A Schematic diagram of ex vivo-expanded UCB-NK cells. B Morphology of NK cells at different cultured times observed via an optical microscope (Scale Bar = 200 μm). C Growth curves of UCB-NK cells from different donors. D Purity of UCB-NK cells as determined by flow cytometry. E Expression of CD19 and CD20 antigens on the surface of different acute leukemia cells. F Cytotoxic effects of UCB-NK cells on different acute lymphoblastic leukemia cells. Data are presented as mean values and S.D. of triplicate samples (*p < 0.05, **p < 0.01, ***p < 0.001, n = 3). UCB-NK, NK cells derived from umbilical cord blood