The effect of TSA (330 nM in C, G, J, K) on eosinophil apoptosis in the presence of IL-5 (0.3 ng/ml) as measured by relative DNA fragmentation assay (A-D), Annexin V binding assay (E-H; Annexin V-FITC: FL1-H and propidium iodide: FL2-H)) and morphological analysis (I-K). Figures in top right hand corner represent the percentage of eosinophils showing decreased relative DNA content (A-C) or total percentage of apoptotic eosinophils (all Annexin V-FITC+ve cells) (E-G). In A-C, E-G and I-J a representative of 6 similar experiments is shown. Mean ± SEM, n = 6 (D, H, K). ***P < 0.001 vs. solvent control in the presence of IL-5 and ### P < 0.001 vs. the control in the absence of IL-5 and TSA.