Regulation of eosinophil differentiation by STAT5.

CD34⁺ cells were transduced with eGFP, STAT5a, or STAT5aΔ750. After 14 and 17 days of differentiation, transduced cells were separated from the nontransduced cells, and cytospins were made. (A) Cytospins were stained with May-Grünwald-Giemsa solution. (B) Eosinophil differentiation was expressed as a percentage of juvenile eosinophils. Data are expressed as averages ± SEMs of 5 independent experiments. (C) Cytospins were fixed with dry acetone for 10 minutes before they were stained with LFB for 2 hours. (D) The percentage of LFB-positive cells was determined by microscopy, and data are expressed as averages ± SEMs of 5 individual experiments. (E) CD34⁺ cells were transduced with eGFP or dominant-negative STAT5b (5BDN). After 14 days of differentiation, cytospins were made of eGFP-positive cells and stained with May-Grünwald-Giemsa solution. The percentages of juvenile eosinophils are expressed as averages ± SEMs of 3 independent experiments. (F) CD34⁺ cells transduced with eGFP, STAT5a, or STAT5aΔ750 were differentiated toward neutrophils. After 17 days of differentiation, eGFP-positive cells were sorted, and cytospins were made and stained with May-Grünwald-Giemsa solution. Neutrophil differentiation is expressed as the percentages of cells consisting of banded or segmented nuclei. Data are expressed as averages ± SEMs of 3 independent experiments.