IL-12 production is also diminished in desensitized DC: restoration by PGE2 plus TNF-α. DC were cultured for 5 days in the presence or absence of LPS, TNF-α, or PGE2 at the concentrations indicated (primary culture). Day-5 DC were recultured with or without LPS (10 ng/mL) or PGE2 (10 μmol/L) plus TNF-α (1,000 U/mL) for 48 hours and supernatants were analyzed for IL-12 levels using a specific ELISA. Data represent mean values of triplicate measurements with SD from one experiment representative of four independent experiments.