Bortezomib impairs DC response to endogenous inflammatory stimuli. DCs generated by culturing adherent monocytes in the presence of GM-CSF and IL-4 for 6 days were harvested and incubated for 24 hours with or without 1 ng/mL bortezomib. CD40L (100 ng/mL), TNF-α (20 ng/mL), or the combination of IL-1 (2 ng/mL), IL-6 (100 ng/mL), PGE₂ (1 μg/mL), and TNF-α (20 ng/mL) was added to the culture medium during the last 16 hours. Cells were subsequently harvested, washed, stained, and analyzed by flow cytometry.