Cathepsin G−/− neutrophils have normal chemotaxis towards a variety of stimuli in vitro and in vivo. (A) Cathepsin G−/− neutrophils have normal chemotaxis in vitro. Bone marrow-derived neutrophils from wild-type (+/+) and cathepsin G-deficient mice (−/−) were added to the top of a modified micro-Boyden chamber with the chemoattractant on the bottom well. Maximally effective concentrations of fMLP (10−4 mol/L), C5a (7% zymosan activated serum), and rhIL-8 (250 ng/mL) were used. Net neutrophil movement per high power field (HPF) is defined as total neutrophils minus neutrophils migrating towards the media control (between 11 and 15 for different experiments). The data represent the mean from 4 individual mice per group each performed in triplicate. Bars represent standard deviations. (B) Quantitation of the total cells and neutrophils in peritoneal lavage fluid from thioglycolate-treated mice. Mice were injected with 2 mL of thioglycolate IP, and, at the indicated times, peritoneal cells were harvested by lavage and quantified. Cathepsin G +/+ and −/− mice demonstrate nearly identical numbers of total cells and neutrophils in the peritoneal harvests. This experiment was repeated 3 times with similar results. (C) Inflammation induced by IP injection of S aureus is not altered in cathepsin G−/− mice. S aureus (108CFU) was injected into the peritoneal cavities of 3 cathepsin G+/+ or −/− mice, and peritoneal lavage was performed 2 hours later. There is no significant difference between the total cells or the number of neutrophils harvested from cathepsin G+/+ or −/− mice. This experiment was repeated twice with similar results.
