Figure 4.
Decreased induction of IL-6 by IL-1 in IRAK-deficient cells. (A) Decreased induction of IL-6 mRNA in IRAK-deficient cells. Control (+) and IRAK-deficient (−) EF cells were treated with IL-1 or TNF-α for 3 h at 37°C. IL-6 mRNA expression in different samples was detected by Northern hybridization and quantitated on a PhosphorImager. (B) Decreased induction of secreted IL-6 in IRAK-deficient cells. Control (+) and IRAK-deficient (−) EF (top) and SF (bottom) cells were stimulated with IL-1 for 8 h at 37°C. The amount of secreted IL-6 in culture supernatants was determined by ELISA.