LXR agonist treatment of DCs leads to altered cytokine production and diminished ability to activate T cells. (A) Immature monocyte-derived DCs (iDCs) were differentiated for 7 days and left untreated (control) or treated from day 2 on with 2 μM of the LXR agonists T0901317 (T09). Mature DCs were obtained from iDCs by incubation with LPS for the last 2 days. After 2 days of LPS-induced DC maturation, cell-free supernatants were analyzed for IL-12p40, IL-12p70, and IL-10 secretion by ELISA in 7 different experiments. (B) Allogeneic T cells were cocultured with untreated or T0901317-treated (T09) iDCs and mDCs, respectively. CD25 and CD69 expression on CD3⁺ T cells was analyzed by flow cytometry after 2 days of coculture in 3 independent experiments. (C) Allogeneic T cells were cocultured for 2 days with DCs that have been treated or not with T09 as in panel B, and cell-free supernatants were analyzed for IL-2 and IFN-γ secretion (n = 3). (D) T-cell restimulaton. After 4 days of coculture, T cells were extensively washed, and restimulated with PMA/ionomycin. Cell-free supernatants of cocultures were analyzed for secretion of indicated cytokines. Significance versus untreated iDCs (*P ≤ .05) or mDCs (***P < .001). Data show the means and SEM of 3 independent experiments.