IL-15, but Not IL-2, Induces Proliferative Activity of Human Ex Vivo Expanded Vγ9Vδ2 T Cells

Human γδ T cells are subdivided into two main subsets, Vδ1 and Vδ2 T cells, based on the expression of the Vδ T cell receptor (TCR) subunit. Most peripheral blood γδ T cells express both Vδ2 and Vγ9 TCR subunits. Vγ9Vδ2 T cells are known to play a key role in immunity against microbial infection and tumors via recognition of non-peptide phospho-antigens. Here, we investigated the antigen-independent cytokine-dependent activation of ex vivo expanded Vγ9Vδ2 T cells. We found that IL-15, but not IL-2, induced cell division in ex vivo expanded Vγ9Vδ2 T cells in the absence of antigen stimulation.