Fig. 1

Expanding Vγ2Vδ2 T cells by pulse zoledronate stimulation with IL-2 increased their purity and number compared with continuous stimulation. a Expansion of Vγ2Vδ2 T cells in response to varying doses of HMBPP and zoledronate with IL-2. Human Vγ2Vδ2 T cells were expanded ex vivo from PBMC by exposure to HMBPP (left panels) or zoledronate (right panels). Human PBMC were cultured in 96-well plates either continuously with varying starting concentrations of HMBPP or zoledronate (open circles) or pulsed with zoledronate for 4 h (closed circles) followed by washing twice. IL-2 was added to 1000 IU on day 3. Thereafter, media was changed every 2–3 d depending on cell growth. On day 14, Vγ2Vδ2 T cell numbers were determined by flow cytometric analysis. b, c Numbers of Vδ2 T cells after 14 d expansion under the indicated conditions with IL-2 for triplicate cultures in either 96-well plates (b) (results for eight donors) or 24-well plates (c) (results for nine donors). PBMC were cultured for 14 d in the presence of IL-2 at 1 × 10⁵ cells/well for 96-well plates or 1 × 10⁶ cells/well for 24-well plates. **p < 0.01 compared to 10 μM zoledronate continuous stimulation using the Mann–Whitney U test. Mean and standard deviation is shown. d Comparison of the purity (left panel) and number (right panel) of Vδ2 T cells expanded by continuous (10 μM) or pulse (100 μM) stimulation with zoledronate with IL-2 in 24-well plates. Each line connects the results for an individual donor. Results for nine donors from (c)