Rapamycin together with TGF-β1, IL-2 and IL-15 induces the generation of functional regulatory γδT cells from human peripheral blood mononuclear cells

• Rapamycin promotes the induction and expansion of regulatory γδT cells in vitro.
• Rapamycin-induced regulatory γδT cells express high levels of Foxp3 and CD25.
• Rapamycin-induced regulatory γδT cells display significant suppressive activities.

Regulatory γδT cell (γδTreg) is a recently reported subset of γδT cells characterized by both expressions of TCRγδ and Foxp3, with potential immunosuppressive functions. However, the further studies of γδTreg are limited mainly due to its low quantities in vivo and the lack of methods to induce γδTreg largely in vitro. Here we show that rapamycin together with TGF-β1, IL-2 and IL-15 can induce and expand γδTregs derived from human peripheral blood mononuclear cells efficiently in vitro. Thus-induced γδTregs express high levels of Foxp3 and CD25, and display significant immunosuppressive activities in vitro.