Human memory Vγ9Vδ2 T cells require homeostatic cytokines for proliferation and differentiation

We have analysed four subsets of human γg9Vδ2 T cells for their capacity to proliferate and differentiate in response to antigen or homeostatic cytokines. Antigen-stimulated cells acquired a central memory (TCM) or effector memory (TEM) phenotype, while IL-15-stimulated cells maintained their phenotype, with the exception of TCM cells, which expressed CD27 and CD45RA in various combinations. These results show that huma nVγ9Vδ2 memory T cells have different proliferation and differentiation potentials and that terminally differentiated (TEMRA) cells result from the TCM subset upon homeostatic proliferation in the absence of antigen.