Effects of in vivo neutralization of MMP-9 and NE on CFU-GM mobilization in mice mobilized by GROβ or GROβ_T, G-CSF, or the combination of G-CSF plus GROβ or GROβ_T. Cohorts of 3 B₆D₂F₁ mice/group received 3 mg/kg anti–MMP-9 on days 0 and 2.5 and were mobilized by a single injection of GROβ or GROβ_T (2.5 mg/kg) on day 5. Mice being mobilized by G-CSF or G-CSF plus GROβ or GROβ_T received 3 mg/kg anti–MMP-9 2 hours before and halfway through (day 2.5) the G-CSF regimen (50 μg/kg, twice daily for 4 days) or daily injections of 1 mg/mouse of the NE selective inhibitor MeOSuc-Ala-Ala-Pro-Val-CMK on each day of G-CSF administration. Mice were analyzed on day 5, 15 minutes after administration of PBS or GROβ. Combined data from 2 experiments are shown. Data are expressed as means ± SEM.