TCL1 inhibits PMA-induced cell death and growth arrest. (A) Viable cell number of Jurkat-C (gray line)– and Jurkat-TCL1 (black line)–treated (solid line) or untreated (dashed line) with PMA was determined at different times, as indicated in the figure, using a cell viability analyzer (Vi-cell XR; Beckman, Hialeah, FL). Data are expressed as mean (± SE) of duplicate samples. Three additional experiments gave similar results. (B) Photomicroscopy of Jurkat-C or Jurkat-TCL1, treated or untreated with PMA for 3 days. Two additional experiments gave similar results. (C) Apoptotic cell fraction of Jurkat-C (gray box) or Jurkat-TCL1 (black box) induced with PMA was determined by flow cytometry as the annexin V–FITC–positive/PI-negative percentage at different times, as indicated in the figure. Data are expressed as mean (± SE) of duplicates samples. Two additional experiments gave similar results. (D) Cell-cycle distribution (S phase) using flow cytometry after PI staining was determined at 24 hours for Jurkat-C (gray box) or Jurkat-TCL1 (black box) induced or not induced with PMA. Three additional experiments gave similar results.