Induction of apoptosis in RBL and MCF7 cells after treatment with anti-Bcl-2-scFv-TAT. Cells were exposed to anti-Bcl-2-scFv-TAT or nonspecific scFv-TAT for 72 hours. Apoptosis was determined by TUNEL assay and the cells were observed under a fluorescent microscope at × 40 magnification. Untreated RBL (Ai) and MCF7 (Bi) cells. RBL (Aii) and MCF7 (Bii) cells exposed to DNaseI as positive control. The cells show DNA fragmentation and fluorescent labeling. RBL (Aiii) and MCF7 (Biii) cells treated with anti-Bcl-2-scFv-TAT. The nuclei of the cells show fragmentation and fluorescent staining. RBL (Aiv) and MCF7 (Biv) cells treated with nonspecific scFv-TAT. The cells show morphologic similarity to untreated cells.