Mobilization of neutrophils from the bone marrow stimulated by MIP-2. Using the in situ perfusion system the rat femoral bone marrow was infused with MIP-2 (1 and 3 nM) or vehicle (PBS/0/1% BSA) for 10 minutes as indicated by the solid bar (D). (A-B) Forward-scatter (FSC) and side-scatter (SSC) FACS plots of leukocytes mobilized from the bone marrow in response to infusion of vehicle or 1 nM MIP-2, respectively. (C) Gates used to determine neutrophil numbers: R1 gate for neutrophils, R2 gate for eosinophil, R3 gate for mononuclear cells, R4 gate for fluorescent beads. (D, left) The kinetics of neutrophil release (•, 3 nM MIP-2; ▴, 1 nM MIP-2; ○, vehicle) and (right) the total number of neutrophils released, mean ± SEM (n = 3-7 separate perfusions). ^*P < .05.