IL-9 increases eosinophil survival.

(A) Eosinophils were cultured as described in Figure 5 for 18 and 36 hours. Morphological alterations of (A) nuclei and (B) trypan blue exclusion were determined as described in Figure 5. A significant difference in the percentage of apoptotic cells was observed between cells cultured with IL-9, IL-5, and medium at 18 hours as well as 36 hours (P < .05). The percentage of trypan blue cells is significantly decreased in IL-5– or IL-9–treated cells compared to medium only at 36 hours of culture (P < .05). (C) DNA fragmentation was determined by DNA staining as described in Figure 5D. Eosinophils were cultured with 10 ng/mL each (i) medium alone, (ii) IL-9, and (iii) IL-5 for 36 hours. (iv) The values are representative of 3 independent experiments.