IPP and prostate cancer: When cultured with pamidronate-treated PC-3 prostate cancer cells that have high intracellular levels of IPP, a higher proportion of Vγ2Vδ2 T cells expanded by pulse stimulation expressed CD107a compared with Vγ2Vδ2 cells expanded by continuous stimulation (50.9% versus 38.2% for purified Vγ2Vδ2 T cells, Fig. 2a, p < 0.05).