Survivin expression and apoptosis in UCB CD34⁺ cells.

(A) UCB CD34⁺ cells were cultured without (upper panels) or with (lower panels) Tpo, SCF, and FL for 48 hours, and survivin expression and apoptosis were quantitated by means of annexin-V/PI. The MCF of FITC-survivin is shown in each dot plot. The percentage of early apoptotic cells (annexin-V^highPI^low) and apoptotic and dying cells (annexin-V^highPI^high) is shown in each blot. Data are representative of 3 experiments. (B) UCB CD34⁺ cells were cultured in the absence of growth factors in 10% FBS for 48 hours and then stained with FITC–anti-human survivin mAb and PE–anti-human active caspase-3 antibody (panel 1). Panel 2 shows forward and side scatter, representing R1 and R2 as viable and apoptotic cells, respectively. Panels 3 and 4 show survivin and caspase-3 counterstaining in the gated R1 and R2 cells from panel 2. Cells in R1 appeared as survivin^high/active caspase-3^low while cells in R2 appeared as survivin^low/active caspase-3^high. Data are from 1 of 3 experiments. Identical results were observed with the use of polyclonal anti–human survivin antibody.