Figure 6.

IL-27 up-regulates IFN-β production in tolerized PMA–THP-1 cells, primary monocytes, and primary macrophages. THP-1 and PMA–THP-1 cells (A) as well as primary monocytes and macrophages (B) were stimulated with LPS (10 ng/ml), IL-27 (100 ng/ml), or LPS + IL-27 simultaneously for 24 h (1°). Cells were washed and challenged with LPS (100 ng/ml) for 4 h (2°). Human IFN-β production was measured in cell-free supernatants. The graphs present mean ± S.E. of at least three independent experiments or at least three independent blood donors. The dashed line depicts the lower sensitivity of the human IFN-β ELISA kit at 3.90625 pg/ml.