Ex vivo granulocytic proliferation and differentiation under different culture conditions including pH, pO₂, and IL-3.

CD34⁺ cells from mobilized peripheral blood were directed along the granulocyte lineage with SCF, IL-6, G-CSF, with or without IL-3, and harvested for total cell counts and characterized by flow cytometry for both cellular phenotype and receptor expression. Production of (A) total cells and the granulocytic subpopulation (B) CD15^dim/CD11b⁻ cells, (C) CD15^bright/CD11b⁻ cells, and (D) CD15^bright/CD11b⁺ cells. Results are expressed as mean values ± SEM (n = 3) relative to the number of CD34⁺ cells used to initiate the cultures. (E) Kinetics of G-CSFR expression presented as mean ± SEM (n = 6) percentage of cells expressing high levels of G-CSFR at different culture times. Significant differences between cultures under the different conditions for each parameter examined are indicated in Table 1. ▴ indicates 5% O₂, pH 7.25, +IL-3; ▵ indicates 20% O₂, pH 7.25, +IL-3; ● indicates 5% O₂, pH 7.4, +IL-3; ○ indicates 5% O₂, pH 7.25, −IL-3.