Figure 2. The combination of IL-2 and IL-15 cytokines enhances the expansion of tetramer-reactive CD3+CD8+ T cells.
PBMCs were stimulated with the corresponding peptide-pulsed autologous PBMCs with irradiation. Different combinations of cytokines IL-2 (10 IU/ml), IL-7 (10 ng/ml) and IL-15 (10 ng/ml) were added to the cell culture as indicated. (A) Representative dot plots of NY-ESO-1 antigen tetramer-positive CD3+CD8+ T cells are shown at Day 7 and Day 10 after in vitro stimulation. (B) The stimulation index of tetramer-positive cells for Melan-A and NY-ESO-1 peptide stimulation under different cytokine conditions. These results are the summary of three experiments: for the Melan-A peptide condition, PBMCs from several patients were repeated three times while; for the NY-ESO-1 peptide condition, PBMCs from one patient were used for three separate experiments. For NY-ESO-1 peptide stimulation, IL-2 plus IL-15 resulted in greater stimulation than IL-2 plus IL-7. The addition of IL-7 to IL-2 and IL-15 did not result in further stimulation. Melan-A peptide-stimulated expansion appeared to be similar across each of the three cytokine conditions.