Nonmalignant T cells stimulate growth of malignant T cells in the presence of SEE. (A) Malignant T cells (MyLa 2059) were grown with or without irradiated nonmalignant T cells (MyLa 3241) with or without SEA (100 ng/mL) or SEE (100 ng/mL) for 48 hours in microtiter plates. The data are representative of 3 independent experiments. Error bars represent SD. (B) Nonmalignant T cells stimulate growth of primary SS T cells in the presence of SEA. Flow cytometric analyses of CFSE expression in malignant cells grown for 3 days in medium (blue line), or with SEA (100 ng/mL) (black line), nonmalignant, blood-derived T cells (MyLa 1885) (green line), or SEA and nonmalignant T cells (red line). The following MFI values were obtained: MFI = 264 (blue line); MFI = 339 (black line); MFI = 90 (green line); and MFI = 70 (red line). The data are representative of 2 independent experiments.