Morphology and phenotypic characterization of CD34⁺ cells undergoing granulocyte or monocyte/macrophage differentiation. Isolated CD34⁺ cells were cultured in the presence of SCF, IL-3, IL-6, and either G-CSF or M-CSF. (A) At the indicated times, cells were cytocentrifuged and stained with May-Grunwald-Giemsa solution (original magnification × 1,000). (B) Bidimensional dot plots of cells labeled with anti-CD34 and anti-CD33 monoclonal antibodies. Numbers within quadrants indicate the percentage of cells in the different populations. Quadrants were set according to isotype-matched negative control stainings. All stainings and dot plots are from a representative experiment (n = 3).