Zoledronate plus IL-2 efficiently expands γδ T cells in the CD56⁺ cell subset. CD56⁺ cells (1.5 × 10⁶/mL) were stimulated with either IL-2 alone (100 U/mL) or with zoledronate (1 μM) plus IL-2. Fresh complete medium containing IL-2 was added every 3 days. After 14 days of expansion, cells were harvested, counted, and analyzed for Vδ2⁺ T-cell frequency by flow cytometry. (A) Plots of CD3 expression against Vδ2 expression show Vδ2⁺ T cells in freshly isolated CD56⁺ cells and show efficient expansion with zoledronate plus IL-2 but not with IL-2 alone. (B) Depletion of CD14⁺ cells before stimulation with zoledronate and IL-2 resulted in substantially diminished γδ T-cell expansion. Data are representative of 3 independent experiments with different donors. Numbers in the upper right quadrants indicate the frequency (in %) of Vδ2⁺ T cells.