Abstract: Cell suicide (apoptosis) is associated with pathogenesis, for example, it is the major cause for the loss of neurons in Alzheimer's disease. Caspase-3 is critically involved in the pathway of apoptosis. Superantibody (SAT)-trans-membrane technology has been used to produce antibodies against the caspase enzyme in an effort to inhibit apoptosis in living cells. The advantage of using trans-membrane antibodies as apoptosis inhibitors is their specific target recognition in the cell and their lower toxicity compared to conventional apoptosis inhibitors. It is shown that a MTS-transport-peptide modified monoclonal anti-caspase-3 antibody reduces actinomycin D-induced apoptosis and cleavage of spectrin in living cells. These results indicate that antibodies conjugated to a membrane transporter peptide have a therapeutic potential to inhibit apoptosis in a variety of diseases.