Selective proliferation of human γδ T cells in vitro

The effect of monoethylphosphate (MEP, commercial available or synthesized) together with IL-2 on the selective proliferation of human γδ T cells in vitro from peripheral blood mononuclear cells (PBMC) of healthy donors and of cancer patients was investigated. The γδ T cells were stimulated by MEP to proliferate in a dose-dependent manner. The effect of synthesized MEP was 10 times greater than that of commercial MEP. When the PBMCs of healthy donors were cultured for 25 d in the medium containing different concentrations of MEP, the total cell number increased about 1000-3000 fold; and the ratio of γδ T cells reached to 70-80%. The selective expansion of γδ T cells depended on the synergic action of MEP and IL-2. The bulk cultured γδ T cells exhibited obvious cytotoxic activities against allogenic tumor cell lines (SQ-5, K562 and Daudi) and autologous tumor cells. The culture system described here not only offers a simple method for obtaining a large number of γδ T cells which may become a new effector in the adoptive immunotherapy, but also provides a useful model for the further studies of the structure and function of γδ T cells in vitro.