Figure 1. CD177^neg and CD177^mix neutrophils show different mPR3 levels but similar mPR3 activity.

(a–c) Pure CD177^mix/mPR3^mix (CD177^mix) and CD177^neg/mPR3^low (CD177^neg) neutrophils were obtained from single individuals by magnetic cell sorting. The presort sample is the initial neutrophil preparation that did not go through cell sorting. Neutrophils were treated with buffer control on ice (resting) or with 10 ng/ml TNFα for 15 min at 37 °C (TNFα). (a) mPR3 amounts were estimated by flow cytometry (upper panel) and expressed as mean fluorescence intensity (MFI, lower panel). A typical sorting experiment is depicted together with the corresponding statistics. (b) After removing degranulated PR3 by washing, the proteolytic mPR3 activity was determined using a PR3-specific FRET assay. (c) The specific activity of mPR3 was calculated. Six independent experiments were performed. * indicates p < 0.05 and ** is p < 0.01.