Mitochondrial survival proteins and procaspases in BL22-treated B-CLL cells. CLL cells were cultured for indicated periods in the presence or absence of 1000 ng/mL BL22. (A) CLL cells were harvested from cultures and lysed. Lysates (50 μg/mL) were separated by SDS-PAGE and were transferred to membranes. Membranes were hybridized with antibodies to proapoptotic or antiapoptotic proteins, to caspase-8 and -9, or to actin (loading control). Blots were developed using chemoluminescent substrates. Approximate sizes of bands are indicated. Shown are results from a representative experiment; a second experiment gave comparable results. (B) CLL cells were permeabilized and stained with antibody YTH-6A7, which recognized conformational changes of Bax but failed to detect the unchanged Bax protein. Cells were analyzed by flow cytometry. Fluorescence intensities of BL22-treated CLL cells are shown as a gray area; intensities of untreated cells are overlaid as a thin line. Shown are results of a representative experiment; 2 additional patient samples gave similar results.