Eosinophil differentiation from CD34⁺ cells ex vivo.

Isolated CD34⁺ cells from cord blood were cultured in presence of SCF, FLT-3, GM-CSF, IL-3, and IL-5 for 3 days (as described in “Materials and methods”). After 3 days of differentiation cells were cultured in the presence of IL-3 and IL-5 only. After 7, 10, 14, and 17 days of differentiation, cytospins were made and (A) were stained with the May-Grünwald-Giemsa solution. (B) The percentage of juvenile eosinophils is expressed as an average ± SEM of 4 individual experiments on each day. (C) Cytospins were also stained with LFB for 2 hours after fixation with dry acetone. (D) The percentage of LFB-positive cells is expressed as an average ± SEM of 4 individual experiments on each day.