Caspaselike activation is required for the generation of LPS-induced survival signals. (A) DCs were left untreated, stimulated with LPS (100 ng/mL), pretreated for 1 hour with PD98059 (30 μM) and stimulated with LPS, or pretreated for 1 hour with zVAD (40 μM) and stimulated with LPS. Thirty minutes after LPS stimulation, cell lysates were analyzed by Western blotting with a specific anti–P-ERK antibody. Anti-ERK antibody was used to control loading. Three independent experiments gave similar results. (B) DCs were left untreated or stimulated with IL1 (100 ng/mL) or LPS, with or without zVAD pretreatment. After 2 hours, cell lysates were analyzed by Western blotting with an anti-FLIP antibody. Antitubulin antibody was used to control loading. Five independent experiments gave similar results.