Peptide-induced apoptosis in primary CLL cells but not in normal lymphocytes. (A) Flow cytometric representations comparing proportions of CLL cells and normal human lymphocytes that are both propidium iodide positive and annexin V positive 24 hours after addition of 10μM TAT-Scr or TAT-IDP_DD/AA. (B) Dose-response curves comparing viability of CLL cells versus normal lymphocytes based on flow cytometric quantification of propidium iodide exclusion 24 hours after adding TAT-IDP_DD/AA. Results are representative of 2 side-by-side comparisons using CLL cells and normal cells from different donors.