Effect of G-CSF on bone marrow myeloid cell adhesion and migration to SDF-1. Unfractionated bone marrow cell populations (1 × 10⁶/mL) were preincubated at 37°C for 18 hours with or without G-CSF (100 ng/mL). (A) After washing, the cells were plated onto SDF-1–coated (4 μg/mL) or diluent only–coated (PBS with 0.1% BSA) microtiter wells and incubated at 37°C for 30 minutes. After removal of nonadherent cells, the remaining cells were detached with 5 mM EDTA, counted, and stained for surface Gr1. The results reflect the differential attachment of Gr1⁺ cells preincubated in medium only or with G-CSF and are expressed as the mean (± SE) percent Gr1⁺ cells attached of input Gr1⁺ cells (results from 5 experiments). (B) After preincubation with or without G-CSF and washing, cells were tested for trans-well migration to SDF-1 (2.4-300 ng/mL) or medium only. Cells recovered in the lower well after 2-hour incubation at 37°C were counted and stained for surface Gr1 expression. Results are expressed as the mean (± SE) percent of migrated Gr1⁺ cells (results reflect the means from 3 experiments). *P < .05 (cells preincubated with medium versus G-CSF).