FIG 1 .

E. chaffeensis blocks PMA-induced ROS generation by BMDMs from WT mice but not by BMDMs from DNase X^−/− mice. BMDMs from WT (A, B) and DNase X^−/− (C, D) mice were preincubated with luminol in HBSSd for 15 min and then incubated with E. chaffeensis (Ech) isolated from infected DH82 cells, DH82 cell lysate, or HBSSd (control [CTL]) at 37°C for 30 min. ROS generation was continuously recorded as the relative chemiluminescence of oxidized luminol after the addition of PMA (0.5 µg/ml, indicated by arrows) (A, C). UN, unstimulated BMDMs in HBSSd without PMA addition. The area under the curve was measured over 60 min after PMA addition and is shown relative to ROS generation in the control with PMA, which was considered 100% (B, D). Results are presented as the mean ± the standard deviation from at least three independent experiments and were compared with a Student t test; *, P < 0.05.