Lymphocyte Death, p53, and the Problem of the “Undead” Cell

Apoptosis is involved in many facets of the development and homeostatic regulation of the immune system (Cohen 1993), including the elimination of self-reactive thymocytes, selection of B lymphocytes within the germinal centres, development of memory T cells and killing of target cells by activated cytotoxic T lymphocytes (Jenkinson et al. 1989; Finkel et al. 1991; Berke 1991; Liu et al. 1989; Akbar et al. 1993).