G-CSF–induced mobilization is enhanced in C3^–/– and C3aR^–/– mice. C3^–/– and C3aR^–/– mice, as well as age- and sex-matched wt mice, were mobilized for 3 or 6 days with G-CSF (250 μg/kg subcutaneously/day) (n = 18 animals/group). (A) Number of MNCs/μL PB in C3^–/– and C3aR^–/– mice compared with age- and sex-matched C57Bl/6 and BALB/c wt mice, respectively. (B) Number of circulating CFU-GM progenitors/100 μLPBinC3^–/– and C3aR^–/– mice compared with wt mice. *P < 0.000 01 compared with wt mice mobilized for 3 days. **P < .000 01 compared with wt mice mobilized for 6 days. Data are expressed as mean ± standard deviation.