Figure 6.

Cleavage of secretory leukocyte peptidase inhibitor (SLPI) by neutrophil proteases and MMPs. (A) SDS-PAGE analysis of SLPI digestion by serine proteases present in neutrophil azurophilic granules, MMP-9, and MMP-8 from neutrophil specific and tertiary granules and other MMPs. Digestions performed at protease/substrate ratios of 1/20 and for 24 h at 37°C. Representative image of two experiments. (B) SDS-PAGE analysis of SLPI digestion by serine proteases at high protease/substrate ratios in comparison with digestion by MMP-9 at a molar protease/substrate ratio of 1/20. Incubation at 37°C for 24 h. Representative image of two experiments. (C) SDS-PAGE analysis of time-dependent SLPI digestion by neutrophil elastase and MMP-9 at protease/substrate ratios of respectively 1/5 and 1/20. Representative image of two experiments.