Death and destruction of activated T lymphocytes.
The massive clonal expansion that occurs during an antigen-specific immune response results in the flooding of immune organs with activated T lymphocytes. At the end of a specific response, the vast majority of these activated T cells are cleared from the immune system. The T cells receive signals through specific death receptors that are expressed as a result of activation. Death receptors transmit their apoptotic signals through the activation of caspases. Function of the death receptors is intimately linked to cell-cycle control, and many cell-cycle control proteins are caspase substrates. Among CD8+ T cells, apoptotic death occurs at a specific site, the sinusoids of the liver. The liver appears to contain a mechanism for the trapping and killing of activated T cells, rendering it an immunologically privileged site.
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Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06520-8011, USA.
D000818:Animals; D017209:Apoptosis; D020169:Caspases; D002453:Cell Cycle; D002454:Cell Differentiation; D006801:Humans; D008099:Liver / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D013601:T-Lymphocytes / Q000276:immunology* / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha; D019014:fas Receptor
D014409:Tumor Necrosis Factor-alpha; D019014:fas Receptor; D020169:Caspases