FIG. 5.

Cell cycle and apoptosis analysis of Jurkat clones after serum starvation. Clonal Jurkat cell lines (10⁶) were serum starved by plating them in 3 ml of IMDM medium supplemented with pen/strep and glutamate in the absence of serum. After 48 h, cells were replated in 3 ml of IMDM supplemented with 10% FBS. An aliquot of cells (5 × 10⁵) was incubated in 70% ethanol, washed with PBS, and stained with propidium iodide and analyzed by flow cytometry immediately after 48 h of serum starvation (Baseline) and 48 h after refeeding of cells in the presence serum (48 Hours). Sub-G₀ (apoptotic cells) and cycling cells (S+G₂/M) were quantified for each Jurkat cell line by flow cytometry, and percentages of cells in each fraction are indicated. The percentage of apoptotic cells (Sub-G₀) and actively cycling cells (S+G₂/M) after serum withdrawal and at 48 h after refeeding cells in the presence of serum are indicated. WinMDI 2.8 was used to quantify the cell subpopulations and analyze the data. Experiments were performed three times; the error bars represent one standard deviation. Statistical analysis was performed by using single-tailed ANOVA and Student t tests ✽, P < 0.05, with Tax1(−)/Jurkat cells as a control.