Tol-DCs possess a stable phenotype.

<p>DCs were carefully washed to eliminate cytokines and dexamethasone, and viable DCs were further re-challenged with 100 ng/ml of LPS or 1 µg/ml of soluble CD40L as second stimuli. After 24 h, the phenotype (<b>A</b>) was analyzed by flow cytometry. Data represent relative MFI increase induced by LPS (n = 6) or CD40L (n = 4) compared to unstimulated iDCs, mDCs or tol-DCs as control. (<b>B</b>) IL-10 concentration is shown in pg/ml. IL-12p70 and IL-23 were not detected (detection limit = 7.8 pg/ml). Student’s <i>t</i>-test: *<i>p</i><0.05, **<i>p</i><0.001. (<b>C</b>) Tol-DCs do not recover the ability to stimulate T cells after re-challenge. T-cell proliferation was determined in triplicate by ³H-thymidine incorporation. IFN-γ and IL-10 production in the supernatant was analyzed.