Figure 1.
In vivo and in vitro treatment with rhG-CSF generates LDGs. C57BL/6 mice were treated with subcutaneous rhG-CSF injections, and cytospin slides were prepared with the low-density fraction (Ficoll-Hypaque gradient) of spleen cells. Hematoxylin and eosin (H&E) staining (A, top panels, 40 × and 100 × magnification). Low-density cells were stained as indicated and analyzed by flow cytometry, gated or not on SSC × FSC plots, as indicated (A, bottom panels). High-density spleen cells from C57BL/6 mice were treated in vitro with rhG-CSF for 15 hours, after which they where passed over a Ficoll-Histopaque Plus density gradient, and the low-density fraction was collected and stained with H&E (B, top panels, 40 × and 100 × magnification) The same population was also stained with the indicated antibodies and analyzed by flow cytometry ungated population (B, bottom panels). Bone marrow HDCs were treated with G-CSF, after which, the low-density cells were obtained and stained with anti-Gr1 antibody. Data shown were obtained from the total, not the gated, population (C). BM LDGs generated in vitro (not gated) and spleen LDGs generated in vivo (gated on high SSC) were analyzed for the presence of immature cells using Sca-1– and Gr1-specific mAb (D). Results are representative of 5 different experiments.