Treatment with γ-secretase inhibitor promotes eosinophil viability. (A) Eosinophils incubated for 24, 48, or 72 hours in the presence of 10 μM GSI or vehicle alone were recovered and incubated on ice with PI (1 μg/mL) for 30 minutes before analysis of PI incorporation by flow cytometry. Data shown are means (± SD) from a representative of 3 independent experiments. (B) Eosinophils recovered after 24 hours of incubation in the presence of 10 μM GSI or vehicle alone were analyzed for exposed annexin V and uptake of PI to differentiate dead from apoptotic cells. Percentages are calculated from total events and represent apoptotic (annexin V⁺, PI⁻) and dead (annexin V⁺, PI⁺) populations. Data shown are from 1 representative of 3 independent experiments.