¹Department of Biochemistry, St. Jude Children's Research Hospital, 332 N Lauderdale Street D-4063C, Memphis, TN, USA

Correspondence: JT Opferman, Department of Biochemistry, St. Jude Children's Research Hospital, 332 N Lauderdale, Memphis, TN 38105, USA. Tel: +901 495 5524; Fax: +901 525 8025; E-mail: joseph.opferman@stjude.org

Received 16 March 2007; Revised 2 May 2007; Accepted 3 May 2007; Published online 15 June 2007.

Abstract

Apoptosis is a conserved genetic program critical for the development and homeostasis of the immune system. During the early stages of lymphopoiesis, growth factor signaling is an essential regulator of homeostasis by regulating the survival of lymphocyte progenitors. During differentiation, apoptosis ensures that lymphocytes express functional antigen receptors and is essential for eliminating lymphocytes with dangerous self-reactive specificities. Many of these critical cell death checkpoints during immune development are regulated by the BCL-2 family of proteins, which is comprised of both pro- and antiapoptotic members, and members of the tumor necrosis factor death receptor family. Aberrations in the expression or function of these cell death modulators can result in pathological conditions including immune deficiency, autoimmunity, and cancer. This review will describe how apoptosis regulates these critical control points during immune development.