IL-5 or GM-CSF priming enhances eosinophil apoptosis in response to Siglec-8 mAb. Eosinophils were preincubated with or without IL-5 or GM-CSF (each at 30 ng/mL) for 24 hours. Antibodies (2.5 μg/mL) were then added to the cultures, as indicated, and apoptosis was analyzed using annexin-V staining 24 hours later. Data are presented as mean ± SEM from 4 experiments. *P < .0005; **P ≤ .005; ***P < .05.