Syntenin expression is induced during eosinophil differentiation. (A) CD34⁺ cells were isolated from cord blood and maintained in FLT-3, SCF, IL-3, GM-CSF, and IL-5. At day 3, cells were transferred to medium containing IL-3 and IL-5 to induce eosinophil differentiation, or to G-CSF–supplemented medium to induce neutrophils. Protein lysates were prepared at the days indicated, and 30 μg of protein was loaded per lane. Blots were incubated with antibodies recognizing syntenin and tubulin as loading control. One of 4 representative Western blots is indicated. (B) Syntenin levels from 4 Western blots were quantified using ImageJ software and mean integrated density is displayed (± SD). **P < .01. (C) Northern blot analysis of HL-60 cells maintained at pH 7.7 for 2 months (HL-60 7.7) that were differentiated toward the eosinophilic lineage by 0.5 mM butyric acid (days of treatment are indicated). Total RNA (20 μg) was blotted and probed for IL-5Rα, syntenin, and GAPDH as loading control. (D) From 2 distinct donors, eosinophils and neutrophils were purified based on Ficoll centrifugation and CD16 selection (magnetic-activated cell sorting; Miltenyi Biotec). Thirty micrograms protein of whole-cell lysate was assessed by Western blotting for syntenin and actin levels.