Fig. 1

Zoledronic acid can be used to expand γ/δ T cells in a GMP-adaptable fashion. Healthy donor-derived peripheral blood mononuclear cells (PBMC) were expanded by either zoledronic acid (ZA) or OKT3 as described in the Methods section. An aliquot was subjected to magnetic-activated cell sorting (MACS) yielding γ/δ⁺ and CD8⁺ T cells. These cells were concomitantly expanded in the presence of OKT3 for 10–11 days. On days 0, 2, 3, 5, and 7, IL-2 was added. On day 3, cells were counted and re-adjusted to 0.2 × 10⁶ cells per ml by adding fresh medium. On day 7, the total cell culture volume was doubled using fresh medium and half of the total volume was transferred to a second culture flask. a + b After 10–11 days, cells were counted and the yield was calculated by dividing final cell count by the number of input PBMC. a Average yield of 11 to 14 independent experiments, each depicted as a different symbol, is indicated as bar. b Average yield of ZA-expanded γ/δ T cells (circles), OKT3-activated PBMC (triangles), and MACS-sorted CD8⁺ T cells (squares) and OKT3-activated-MACS γ/δ T cells (diamonds) – before and after OKT3-mediated expansion. Data are presented as means of 11 to 14 independent experiments. c Composition of cell populations before and after purification and expansion. γ/δ T cells are selectively expanded from donor-derived PBMC by ZA. Shown are double stainings for γ/δ and CD3 (left-hand side), and γ/δ and CD8 (right-hand side). Exact percentages of the different populations are summarized in Additional file 1: Table S1. Data are presented as means of 7 to 10 independent experiments