How T lymphocytes switch between life and death.
Eur J Immunol
; 36(7): 1654-8, 2006 Jul.
Article
em En
| MEDLINE
| ID: mdl-16791883
ABSTRACT
While insufficient cell death of activated T cells can result in autoimmune disorders, elimination of too many T cells can lead to immunodeficiency. Therefore, T lymphocyte fate is highly regulated and requires that cells can switch from an apoptosis-resistant towards an apoptosis-sensitive state. This switch is tightly controlled by various effector molecules. Basically, two separate pathways control the fate of antigen-activated T cells activation-induced cell death (AICD) and activated T cell autonomous death (ACAD). Autoreactive T lymphocytes are eliminated by restimulation via their T cell receptor (TCR) and undergo AICD involving death receptors (extrinsic pathway). In contrast, ACAD can lead to T cell deletion without TCR restimulation, and is determined by the ratio between anti- and pro-apoptotic Bcl-2 family members at the mitochondria (intrinsic pathway). While the extrinsic and the intrinsic pathway lead to caspase activation, non-caspase proteases (e.g., cathepsins) can be released by the lysosomes and might contribute to AICD as well as to ACAD. Activated T cells poses cell death escape mechanisms which are needed for survival of (memory) T cells, but are deleterious for autoimmune disorders or progression of T cell lymphomas.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Linfócitos T
/
Apoptose
Limite:
Animals
/
Humans
Idioma:
En
Ano de publicação:
2006
Tipo de documento:
Article