Effective IDO induction in DCs does not require canonical NF-κB activation. (A) Monocyte-derived DCs were either left unstimulated or matured with LPS or CD40L in the presence or absence of NBD/MUT peptides. After 48 hours, the cells were extensively washed and lysed in sample buffer. Cell lysates were analyzed by Western blotting for IDO content, and β-actin as loading control. One representative experiment of 3 is shown. (B) Monocyte-derived DCs were either left unstimulated or matured with CD40L in the presence or absence of NBD/MUT peptides. After 48 hours, cells were harvested, extensively washed in cold PBS, and freeze-dried. Subsequently, IDO enzymatic activity in the samples was evaluated by testing the capacity to degrade tryptophan into kynurenine. Results represent mean plus or minus SEM from 3 independent experiments (*P < .05).