Selection of HA-1–specific CTLs restricted by nonself HLA molecules using HA-1^A2 tetramers.

(A) The percentage of HA-1^A2 tetramer–positive CD8⁺ T cells after sorting. HA-2^A2 tetramers were used as specificity control. (B) The cytotoxic activity of sorted T cells against T2 cells pulsed with HA-1 peptide and control H-Y peptide (both 1 μg/mL) without or with the addition of cold K562 or HLA-A2⁺/HA-1⁻ EBV-LCLs (cold target cell–to–hot target cell ratio = 20). The results are expressed as the mean of the duplicate cultures at an effector-to–hot target cell ratio of 1:1.