CFU-GM mobilization, proteases, and PMNs in MMP-9^–/– mice. Cohorts of 3 C57Bl/6 male and female mice/group were mobilized by a single injection of GROβ_T (2.5 mg/kg), a multiday regimen of G-CSF (50 μg/kg, twice daily for 4 days) or administration of GROβ_T on day 5 following the G-CSF regimen. (A) Mean ± SEM increase in CFU-GM/mL blood from 2 experiments. (B) Representative zymograms of plasma and marrow extracts from female MMP-9^–/– and MMP-9^+/+ mice. (C) Mean ± SEM increase in CFU-GM/mL blood in male and female MMP-9^–/– mice receiving anti–MMP-9 antibody during the mobilization regimen. Right panel insert confirms activity of anti–MMP-9 in blocking mobilization by GROβ_T and reducing mobilization by G-CSF in normal mice as described in Figure 2. (D) Mean ± SEM NE and CG in the marrow extravascular compartment. Data from 2 experiments are shown. (E) Mean ± SEM absolute neutrophil count (ANC) and percent PMN/mL blood from 2 experiments.