Figure 2.

The combination of IL-1β, TNF-α, and IFN-γ increase nitrite production and iNOS expression. The conditions are the same as in Figure 1 and nitrite measurement in the media and iNOS immunoblotting were performed as stated in MATERIALS AND METHODS. The immunoblotting was normalized to actin. A shows nitrite secretion into the media, B shows the effect of the mixture of cytokines on iNOS protein levels as measured by immunoblotting, and C shows a representative immunoblot for iNOS and actin. The results are the mean ± SE of six experiments. The asterisk signifies P < 0.05 compared with the matched control without cytokines. The cytokine mixture of IL-1β, TNF-α, and IFN-γ increased iNOS protein and nitrite secretion independent of the state of differentiation.