Blockade of JNK/AP-1 activation and protein neosynthesis restores CD40-mediated survival of NF-κB–deficient DCs. (A) Pharmacologic inhibition of JNK/AP-1 activation, but not of p38 MAPK or MEK/ERK function, restores CD40L-dependent survival in NF-κB–deficient DCs. DCs were transfected with pIRES2-EGFP or IκBαAA-pIRES2-EGFP. FACS-sorted transfectants were cultured for 3 days in the absence or presence of CD40L. Inhibitors were used at 10 μg/mL (cycloheximide, CHX) or 1 μM (SP600125, PD169316, U0126). (B) Transfection of DN-JNK restores CD40L-dependent survival in NF-κB–deficient DCs. DCs were transfected with IκBαAA or control vector together with plasmids encoding DN-JNK, WT-JNK, or empty control vector on day 11.5. DCs were sorted and reseeded on day 12, exposed to CD40L or medium only, and cultured for the indicated time periods. (A-B) Results are presented as mean x-fold alteration of survival (mean ± SD of triplicate experiments) relative to the survival of vector-transfected DCs cultured in medium only. (B) Data were normalized to control cells for each individual time point presented. Results are representative of at least 3 independent experiments.