Figure 1.

Exploration of α1PI for investigation of the respective role of constitutive and inducible PR3^mbin neutrophils activation by anti-PR3 antibodies. The diagram illustrates two distinct pool of PR3^mb colocalized with NB1 (CD177) (34) on activated neutrophils: one catalytically inactive, which is α1PI-resistant (constitutive PR3^mb), and the other in an activatable conformation that is α1PI-sensitive (induced PR3^mb) (10, 11). The property of α1PI to discriminate between constitutive and induced PR3^mb was explored to assess their relative role in immune activation of neutrophils by anti-PR3 mAbs and PR3-ANCA. α1PI, alpha-1 protease inhibitor; ANCA, antineutrophil cytoplasmic antibody; PR3, proteinase 3.