ERK and p38 are activated by Fn or TNF-α in peripheral blood eosinophils.

Eosinophils were preincubated for 30 minutes with dimethyl sulfoxide alone or 50 μM PD98059 (PD), followed by 30 minutes with medium alone (Resting), TNF-α, fibronectin (Fn) (as described in “Materials and methods”), or TNF-α plus Fn (T + Fn). The cells were lysed, analyzed on a 10% SDS-polyacrylamide gel electrophoresis, and immunoblotted with antiactive ERK, antiactive p38, antiactive JNK, or anti-ERK1/ERK2 (Total-ERK). The signals obtained by autoradiography are shown (A) and are representative of 3 different donors. (B) The signals were quantified and normalized to total-ERK. Each value represents the mean (SEM) of 3 different donors.