Allergen-specific IL-4-, IFN-γ–, and IL-10–secreting T cells represent Th2-, Th1-, and Tr1-like cells. (A) IL-10, IL-13, IFN-γ, and TGF-β mRNA were quantified by real-time PCR immediately after isolation of Der p 1– or Bet v 1–specific, cytokine-secreting T cells and their relative expression compared with the housekeeping gene EF-1α. The same results were obtained in three independent experiments. (B) Bet v 1–, Der p 1–, and Cor a 1–specific IL-4–, IFN-γ–, and IL-10–secreting T cells (one allergic and one healthy donor each; closed symbols, allergic donors; open symbols, healthy donors) were in vitro expanded for 2 wk, and their cytokine profile was determined in supernatants by ELISA 72 h after anti-CD2, anti-CD3, and anti-CD28 mAb stimulation. (C) Intracytoplasmic cytokine profile of in vitro–expanded allergen-specific T cells (the same results were obtained in 10 additional experiments). Percentage of positive cells is shown in each quadrant.