EAPB0203 induces apoptosis in HTLV-I–positive and –negative human T-cell lines. (A) Annexin-V binding. Cells were treated for 24 hours with EAPB0203 (5 μM). Using FITC-conjugated annexin-V membrane staining and PI nuclear counterstaining, apoptotic cells (FITC⁺ PI⁻) and dead cells either necrotic or postapoptotic (FITC⁺ PI⁺) were analyzed by fluorescence microscopy. (B) Hoechst 33 342 staining. Cells were treated with EAPB0203 (5 μM), stained with Hoechst 33 342, and analyzed under ultraviolet filter pack. The percentage of apoptotic cells displaying intensely fluorescent, condensed chromatin, are presented.