Addition of IL-6 during DC generation leads to an impaired DC phenotype. DCs generated in the presence of IL-6 were analyzed for surface expression of CD1a, CD14, CD83, and CD86. LPS was added 24 hours before harvesting of the cells. Open histograms represent staining with the indicated antibody; shaded histograms, the isotype control. The level of surface expression is indicated as mean fluorescence intensity.