Reactivity to WT1 peptide in PBMCs after the TCR-T cells transfer. PBMCs collected from TCR-WT-07-M03 in cohort 2, before and after transfer of the TCR-T cells. CD8⁺ T-cells were selected, stimulated in vitro with WT1 peptide, and subjected to an ELISPOT assay. The target T cells were T2A24 cells pulsed with WT1 peptide. T2A24 cells alone were used as control targets, and WT1-specific TCR-T cells from a healthy volunteer were used as positive effector cells.