CD107a/b-degranulation assay. PBMCs were peptide-stimulated over a course of 9 days. The first analysis was performed on day 16 without further restimulation; the second analysis was performed on day 21 after 7 days of restimulation with CD3/CD28-coated beads. After gating cells with the forward and side light scatter properties of lymphocytes, the degranulation was measured as percentage of CD107a/b-positive cells of CD3/CD8-positive cells. gp100 was used as negative control; CMV-pp65 was used as positive control. Two different cell lines were used as targets. (A) FACS dot plots of 2 representative subjects (UPN T6 and UPN T46) for T2 cells as targets. (B) FACS dot plots of 2 representative subjects (UPN T14 and UPN T46) for K562-A2 cells as targets.