Receptor-mediated Apoptosis in T Lymphocytes
This extract was created in the absence of an abstract.
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)...
