Receptor-mediated Apoptosis in T Lymphocytes (original) (raw)

1. J. ZHANG,
2. A. DEYOUNG,
3. H.G. KASLER,
4. N.H. KABRA,
5. A.A. KUANG,
6. G. DIEHL,
7. S.J. SOHN,
8. C. BISHOP, and
9. A. WINOTO
10. University of California, Berkeley, Department of Molecular and Cell Biology, Division of Immunology and Cancer Research Laboratory, 469 LSA, Berkeley, California 94720-3200

Excerpt

Each T lymphocyte carries a unique T-cell receptor(TCR) on its cell surface used to recognize foreign peptidesin the context of the major histocompatibility complex(MHC) proteins. Central to this notion is the need to eliminate T cells that are reactive to self-peptides/MHC. Apoptosis of these self-reactive cells takes place in two different phases: one during T-cell development (negativeselection) and another after T cells have matured (peripheral tolerance). It is thought that for immature T cells, astrong signal through the TCR leads to apoptosis, whereasa weak signal results in differentiation (positive selection).For mature T cells, only repeated TCR stimulation, whichpresumably mimics signals from self-peptide/MHC, leadsto apoptosis. How differential signaling in various stagesof T-cell development leads to these opposite outcomes isnot completely clear (Nossal 1994; von Boehmer 1994;Nagata and Golstein 1995; van Parijs and Abbas 1996;Amsen and Kruisbeek 1998; Sebzda et al. 1999)...