Survival of PBMC and IL-2–dependent activated T cells in the presence of GSH and L-cysteine. IL-2–deprived activated T cells (A) and freshly isolated PBMC (B) were incubated under various conditions for 5 and 8 days, respectively. Cells were incubated alone, with IL-2 (5 ng/mL), or with GSH, GSSG, L-cysteine, and L-cystine, each at concentrations of 3 mmol/L (A) or 1 mmol/L (B). Values are means ± standard error of mean (SEM) (n = 3 or 4). The results are representative of three independent experiments.