Three-color flow cytometry of different hematopoietic lineages from bone marrow, spleen, and thymus. After lysis of red blood cells, leukocytes were triple-stained with antibodies against the respective lineage markers (x-axis, PE) integrin β1 (y-axis, APC) and CD41 (not shown, FITC). CD41⁺ cells were excluded from the analysis by gating to minimize contamination by adhering platelets. A second gate was set to select cells positive for the respective lineage markers. The quadrants were set based on isotype controls. Analysis of peripheral blood leukocytes with a gate on CD41⁻ cells led to similar results (not shown).