FIG. 3.

Cell cycle analysis of cytokine-stimulated lymphocytes. (A) Time course of entry into the S+G₂M stages of the cell cycle. The percentage of dividing cells was determined at each of the indicated time points by propidium iodide staining of control (squares) and Stat6-deficient (circles) lymphocytes which had been activated with ConA for 72 h and then cultured in the presence of 1,000 U of IL-4 per ml (solid symbols) or in the absence of IL-4 (open symbols). The standard error for all points was less than 5%. (B) Cell cycle analysis of lymphocytes following 30 h of cytokine stimulation. Control (+/+) or Stat6-deficient (−/−) lymphocytes were activated with ConA for 72 h and then cultured for an additional 30 h in the presence of 200 U of IL-2 or 1,000 U of IL-4 per ml or in the absence of IL (unstimulated). Numbers to the left of the major G₀/G₁ peaks represent the numbers of apoptotic events expressed as percentages of all events analyzed by flow cytometry. Numbers to the right of the major G₀/G₁ peaks represent the numbers of cells in the S+G₂M phases of the cell cycle expressed as percentages of all live cells, as calculated by the CellFit analysis program.