IL-10 production was accessed in supernatant after expansion of CD25int mTreg and naive Treg cells in TAC or DMSO in 2 donors (Figure 5A, donor 1; B, donor 2). CD25int mTreg produced substantially more IL-10 than naive Treg cells. Expansion when exposed to TAC significantly reduced IL-10 production by both Treg cell populations, with IL-10 production by naive Treg cell almost completely ablated but production by CD25int mTreg remaining relatively high. Remaining IL-10 production when exposed to TAC by CD25int mTreg cells may explain the greater stability of suppressive function of CD25int mTreg cells compared with naive Treg cells.