Figure 2.

Vδ2 cell degranulation within zoledronic acid (ZA) -treated peripheral blood mononuclear cells (PBMCs) is monocyte-dependent. (a) γδ T-cell-depleted PBMCs were pulsed for 4 hr with 0, 1 or 10 μm ZA, then washed and cultured overnight in fresh media. Cell-free conditioned media were collected and cultured overnight with purified γδ T cells before measuring CD107a expression on Vδ2 cells. For matched donors, CD107a expression was also measured on Vδ2 cells in PBMCs that had been pulsed for 4 hr with 0, 1 or 10 μm ZA, then washed and cultured overnight in fresh media. Means ± SD for three different donors are shown. (b, c) PBMCs or monocyte-depleted PBMCs were cultured overnight with 0, 1 or 10 μm ZA before flow cytometric analysis of CD107a and CD107b expression on Vδ2 cells. (b) Flow cytometric plots representative of three different donors showing CD14 expression on PBMCs, monocyte-depleted PBMCs and the depleted monocytes. Debris was excluded according to forward scatter (FSC) and side scatter (SSC) using gate 1 (G1). CD14 expression on G1 cells is shown. The filled and open histogram plots are expression levels for CD14 and isotype control antibodies, respectively. Numbers are percentages of cells. (c) Means ± SD for three different donors for the percentage of CD107a⁺/CD107b⁺ cells within Vδ2 cells. For (a) and (c), ** indicates a P value < 0·01 for paired t-tests between the data sets at 1 μm ZA.