FIGURE 1.

LT enhances degradation of IκBα and IκBβ but not IκBϵ. Cells were treated with medium alone or medium containing LT (100 ng/ml LF + 500 ng/ml PA), 0.2 ng/ml TNF, or both. Whole cell lysates were analyzed by Western blot for expression of IκBα (A), IκBβ (B), and IκBϵ (C) as described under “Experimental Procedures.” At least four blots were performed for each protein at each time point, and representative blots are shown. Graphs represent Western blot densitometry (n ≥4) for medium (diamond, solid line), LT (square, dashed line), TNF (triangle, solid line), and LT + TNF (×, dashed line). Data were normalized relative to cells treated with medium alone and presented as means ± S.E. D, IκBβ immunofluorescence at 24 h. Representative images are shown. M, medium; L, LT; T, TNF; L + T, LT + TNF. **, p < 0.01 versus medium; ††, p < 0.01 versus TNF; †, p < 0.05 versus TNF.