Signaling pathways involved in the regulation of IDO1 expression and activity induced by IFNγ or LPS in HeLa cells and DCs. HeLa cells or DCs were treated with either IFN-γ or LPS with or without the inhibitors at the indicated concentrations for 2 days, and the cells were lysed and analyzed by Western blot using an anti-IDO or anti-GAPDH antibody. Representative data of 3 independent experiments are shown: IFN-γ–treated HeLa cells (A) and DCs (C), and LPS-treated DCs (E). Kyn levels in the supernatants from these treated cells were determined spectrophotometrically. Representative data of 3 independent experiments are used in the graphs: IFN-γ–treated HeLa cells (B) and DCs (D), and LPS-treated DCs (F). In panels A, C, and E, the vertical lines represent where 2 separate images were aligned. Error bars represent SD.