Ecto-ATPase CD39 Inactivates Isoprenoid-Derived Vγ9Vδ2 T Cell Phosphoantigens

In humans, V gamma 9V delta 2 T cells respond to self and pathogen-associated, diphosphate-containing iso-prenoids, also known as phosphoantigens (pAgs). However, activation and homeostasis of V gamma 9V delta 2 T cells remain incompletely understood. Here, we show that pAgs induced expression of the ectoATPase CD39, which, however, not only hydrolyzed ATP but also abrogated the gamma delta T cell receptor (TCR) agonistic activity of self and microbial pAgs (C-5 to C-15). Only mevalonate-derived geranylgeranyl diphosphate (GGPP, C-20) resisted CD39-mediated hydrolysis and acted as a regulator of CD39 expression and activity. GGPP enhanced macrophage differentiation in response to the tissue stress cytokine interleukin-15. In addition, GGPP-imprinted macrophage-like cells displayed increased capacity to produce IL-1 beta as well as the chemokine CCL2 and preferentially activated CD161-expressing CD4(+) T cells in an innate-like manner. Our studies reveal a previously unrecognized immunoregulatory function of CD39 and highlight a particular role of GGPP among pAgs.