Developmental potential of cells after culture with Notch ligand and cytokines.

Number of cells (A) and antigen expression (B) were determined after Lin⁻Sca-1⁺c-kit⁺ cells incubated for 28 days with 4GF and I-Delta1^ext-IgG were transferred to new cultures containing 4GF, I-Delta1^ext-IgG plus IL7 (●) or 4GF, I-Delta1^ext-IgG plus GM-CSF (▴). Antigen expression was determined 7 days after transferring to cultures with additional growth factors. Those with GM-CSF are shown. In dot plots, x-axis is log fluorescence intensity after staining with antibodies to Sca-1 or Thy-1; y-axis, log fluorescence intensity after staining with antibodies to c-kit or CD25. Fewer than 0.5% of cells stained with either or both isotype control antibodies. In histograms, x-axis is log fluorescence intensity after staining with GR-1; y-axis, cell number; solid line, staining with GR-1; dotted line, staining with isotype-matched control antibody.