NF-κB inhibition impairs survival of mature eosinophils. (A) Western blot of p65 from cytoplasmic (cyt) and nuclear (nuc) protein fractions of peritoneal eosinophils isolated from 2 IL-5 transgenic mice.¹⁶  Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and histone H2B were used as cytoplasmic and nuclear marker proteins, respectively. (B) Blood eosinophils (Siglec-F⁺SSC^high) from wild-type BALB/c mice were stained intracellularly for p65 (black outline) and an isotype control antibody (gray shade). Plots are representative of 3 independently analyzed mice. (C) Eosinophils were pretreated with inhibitors for STAT5, p38, or NF-κB and then cultured in the presence of IL-5 for 72 hours. Dot plots show representative annexin V/propidium iodide (PI) staining of NF-κB–exposed eosinophils vs dimethylsulfoxide (DMSO) vehicle control. Bar graphs show mean + SEM of apoptotic eosinophils pooled from 3 independent experiments (n = 8-9; ***P < .0001).