IL-18 production by C/EBPε−/− bone marrow macrophages before and after LPS (100 ng/mL) stimulation.

After 10 days of culturing, the macrophages were extensively washed and incubated for 24 hours in fresh medium containing LPS. Cells were harvested and counted, and IL-18 secretion in the culture medium was quantitated by ELISA. (B) Whole cell protein extracts were prepared from these cells and analyzed by Western blotting using a polyclonal anti–IL-18 antibody. Fold change was measured by densitometry. Blots were probed with anti–GAPDH antibody as a control.