Killing of S aureus by control and NET-forming neutrophils. (A) S aureus was added to control neutrophils (white bars) and neutrophils forming NETs after incubation for 120 minutes with 20 ng/mL PMA (hatched bars). CD (10 μg/mL), DNase I (100 U/mL), or both (C) were added 20 minutes before addition of bacteria. (B) Same as panel A, with killing calculated after DNase I (100 U/mL) was added at the end of incubation with bacteria to the wells not already containing it. Gray bar represents killing calculated after addition of heat-inactivated (10 minutes, 70°C) DNase. (C) Same as panel B, with killing calculated using the total number of bacteria in the wells (ie, bacteria in the cell medium plus bacteria recovered from the wells after aspiration of the cell medium and washing). Error bars represent SEM (n = 4-6). With heat-inactivated DNase (n = 3). **P < .01 (Student t test on paired data).