Adenosine regulates cytokine production of mature PDCs. PDCs (2.5 × 10⁵ cells per milliliter) were activated with CpG ODN 2006 and CD40L-transfected BHK cells in the presence or absence of 100 μM adenosine, either directly ex vivo or after culture with IL-3 for 60 hours. Supernatants were harvested after 48 hours, and IFN-α (A), IL-6 (B), IL-12p40 (C), and IL-12p70 (D) concentrations were measured by ELISA. Data represent mean ± SEM of 3 different donors. *P < .05.