Combined use of IL-21 and CD25 depletion enhances generation of WT-1– and NY-ESO-1–specific CTL responses. Unmanipulated or CD25-depleted PBMCs from an HLA-A2⁺ patient with a WT-1⁺ ovarian cancer (top panels) and a patient with melanoma (NY-ESO seropositive; bottom panels) were stimulated as described in Figure 1.