Bet-specific iTreg induced by IL-10 DC exhibited an activated phenotype after Bet-and Cor-specific restimulation
Several studies revealed an anergic phenotype of CD4+CD25+FOXP3+natural Treg and iTreg, in particular of iTreg induced by IL-10 DC.35,38,42,44 In order to prove the allergen-specific and cross-reactive induction of T cell anergy in our system, we have performed restimulation experiments with autologous mDC0, mDCBet or mDCCor, respectively (see Supplementary Methods). Compared to control T cells (Teff0), restimulation of TeffBet with mDCBet led to a significantly increased and in the case of mDCCor slightly enhanced Teff proliferation, demonstrating the induction of both a Bet-specific and cross-reactive, Cor-specific T cell response (Figure 2A). However, also restimulation of iTregBet with mDCBet or mDCCor resulted in a very pronounced and significantly enhanced T cell proliferation, compared to Teff0. iTregBet proliferated even stronger compared to TeffBet, indicating that allergen-specific iTreg did not display an anergic but activated phenotype after specific (Bet) or cross (Cor)-specific restimulation (Figure 2A). In contrast to iTregBet, iTreg0 exhibited a significantly lower proliferation and remained anergic regardless of the allergen-specific or cross-specific restimulation with mDCBet or mDCCor (Figure 2B).