Enhanced expandability of WT1-siTCR–transduced CD8⁺ T cells by repetitive stimulation with WT1 peptide in vitro. (A) WT1-siTCR–transduced CD8⁺ T cells (top) and WT1-coTCR–transduced CD8⁺ T cells (bottom) were repetitively stimulated with HLA-A*24:02-positive LCLs loaded with WT1 peptide in vitro. Total cell number (▵), percentage of Vβ5.1-positive cells (■), and percentage of HLA-A*24:02/WT1 tetramer-positive cells (●) were monitored after stimulation with WT1 peptide. Cytotoxic activities of WT1-siTCR–transduced CD8⁺ T cells and WT1-coTCR–transduced CD8⁺ T cells against WT1 peptide-loaded (gray bars) or -unloaded C1R-A*24:02 cells (white bars) are also shown. (B) Percentages of HLA-A*24:02/WT1 tetramer-positive cells among WT1-siTCR–transduced CD8⁺ T cells from 5 donors (○) and those in WT1-coTCR–transduced CD8⁺ T cells from 3 donors (●) before and after stimulation with WT1 peptide.