Concentration-dependent effect of IL-9 on eosinophil survival.

(A) Cells stimulated with IL-5 (▧,10 ng/mL) were used as a positive control (*P < .05). Freshly purified peripheral blood eosinophils stimulated for 18 hours with a graded amount of IL-9 (▪) showed fewer apoptotic cells compared to medium alone (■, †P < .01 at 10 ng/mL of IL-9). (B) Data from panel A are presented as the percentage of inhibition compared to the control (medium alone). The assays were performed in duplicate on eosinophils from the same donor. These results are representative of 3 independent experiments performed under the same conditions.