Cytoprotection by T-cell supernatants. (A) Cells from patient CLL16 were incubated for 20 minutes in the absence or presence of 20% T-cell supernatant (spnt) and/or PF-956980, as shown. Proteins were extracted and analyzed by Western blotting using the antibodies indicated. (B) Cells from patient CLL18 were left untreated or incubated with 100μM chlorambucil, as indicated, washed, and resuspended in fresh medium. PF-956980 and/or 20% T-cell supernatant were added, as indicated. After 18 hours of further incubation, proteins were extracted and PARP cleavage was quantified by Western blotting. Data are representative of 3 experiments.