Cytotoxic activity of γδ T cells after in vitro expansion with ZOL. (A) Cytotoxicity of Vγ9Vδ2 cells against AML, BCP-ALL, or T-ALL blasts at 20:1 E:T ratio is shown. One representative experiment using cells collected from patient 2 is reported. Vγ9Vδ2 cells were tested against leukemic blasts left untreated (medium), ZOL sensitized (ZOL), or treated with ZOL and MEV (ZOL+Mev). In some experiments, Vγ9Vδ2 cells were preincubated with an anti-TCR Vγ9 (ZOL+αVγ9) or an anti-NKG2D (ZOL+αNKG2D) mAb. Inset shows 1 representative experiment performed at different E:T ratios (from 20:1 to 1.2:1) using Vγ9Vδ2 cells collected from patient 2 against 1 AML sample treated with ZOL. (B) CD107a degranulation assay was performed using Vγ9Vδ2 cells (n = 10) against myeloid and lymphoid leukemia cells untreated (medium) or ZOL sensitized. Pooled results are shown. Whisker lines represent the highest and lowest values; horizontal lines represent median values. (C) One representative experiment with Vγ9Vδ2 T cells after in vitro expansion of PBMCs from patient 6. Double staining with anti-Vδ2 phycoerythrin and anti-CD107a allophycocyanin is shown on gated γδ⁺Vδ2⁺ T cells.