Figure 2.

Ragweed pollen extract (RWE) leads to intracellular reactive oxygen species (ROS) production and ROS inhibitors abolish interleukin-1β (IL-1β) production. (a) THP-1 cells were loaded with H₂DCFDA, treated with various combinations of 100 μg/ml RWE, 100 μm NADPH and 1000 ng/ml lipopolysaccharide (LPS), and changes in the intracellular ROS level were measured using flow cytometry for the indicated time interval; 1 mm H₂O₂ was used as a positive control. Mean intensity of fluorescence was calculated from the positive area defined by the stained cells. (b) THP-1 cells were pre-treated with 30 mm NAC, 300 μm MitoTempo or 10 μm DPI for 1 hr then treated with 100 ng/ml LPS in the presence or absence of 10 μg/ml RWE and 100 μm NADPH. Twenty-four hours after treatment the secreted IL-1β was measured from the collected supernatants in triplicates by an ELISA method. Results were obtained in three independent experiments, and a representative result set is shown. *P < 0·1, **P < 0·01, ***P < 0·001.