EPO activates mouse and human DCs. (A) Characterization of recombinant EPO activity and conditions for enzyme inactivation. (B) Mouse BMDC activation status and (C) cytokine production was analyzed after incubation with increasing concentrations of EPO with or without resorcinol (Res), heat-inactivated EPO (xEPO), or a positive control replication-deficient vesicular stomatitis virus. (D) BMDCs were conditioned for 16 h with media, EPO, or CT as a positive control before stimulation with media or LPS and analysis for IL-12p40 by intracellular cytokine staining. (E) Human monocyte-derived DC activation status and (F) cytokine production was analyzed after incubation with increasing concentrations of EPO with or without resorcinol, xEPO, or 3-nitrotyrosine (3NT). (G) Viability of mouse and human DCs by PI exclusion and flow cytometry. Mean ± SEM, n = 3–8 from 2–4 experiments for mouse DCs; n = 16 from 2–4 experiments for human DCs. *, P < 0.05 vs. media. ^#, P < 0.05 versus 4 µg/ml EPO.