A novel strategy using single-chain antibody to show the importance of Bcl-2 in mast cell survival

Apoptosis or programmed cell death plays an important role in a wide variety of physiologic processes and is regulated by proteins of the Bcl-2 family consisting of both antiapoptotic and proapoptotic factors. The direct involvement of the Bcl-2 protein family in the process of mast cell apoptosis has not been clarified. In the present work we have used a single-chain antibody (scFv) raised against Bcl-2 derived from a semisynthetic human phage-display antibody library. The addition of TAT sequence, which is responsible for translocation through the membrane, endows the antiBcl-2-scFv with the ability to penetrate living cells. Moreover, it specifically neutralizes Bcl-2 intracellularly by binding to the BH1 domain and eradicates its antiapoptotic activity in 2 types of mast cells and in a human breast cancer cell line. (C) 2003 by The American Society of Hematology.