Apoptosis by IL-2 deprivation in human CD8+ T cell blasts predominates over death receptor ligation, requires Bim expression and is associated with Mcl-1 loss.
Mol Immunol
; 44(6): 1446-53, 2007 Feb.
Article
in En
| MEDLINE
| ID: mdl-16806475
The mechanisms responsible for the down-modulation of the activation of separated CD4(+) or CD8(+) human T cell blasts were studied using cells obtained from healthy donors. In the absence of IL-2, human CD4(+) T cell blasts were sensitive to both FasL and Apo2L/TRAIL, but human CD8(+) T cell blasts died, with no additional effect of death receptor ligation. CD8(+) T cell blasts were more sensitive than CD4(+) T cell blasts to apoptosis induction by IL-2 deprivation, which was associated with a decrease in the expression of anti-apoptotic proteins of the Bcl-2 family, especially of Mcl-1 in CD8(+) T cell blasts. The maintenance of high levels of Bim expression was also necessary, since down-modulation of Bim expression by siRNA in normal human CD8(+) T cell blasts greatly reduced apoptosis by IL-2 deprivation. These data, together with previous works, point to an important role of the presence or absence of immuno-stimulatory cytokines in the type of regulation of human CD8(+) T cell responses (death by cytokine deprivation versus death receptor inhibition of cytokine-dependent growth).
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Lymphocyte Activation
/
Proto-Oncogene Proteins
/
Interleukin-2
/
Apoptosis
/
CD8-Positive T-Lymphocytes
/
Proto-Oncogene Proteins c-bcl-2
/
Apoptosis Regulatory Proteins
/
Receptors, Death Domain
/
Membrane Proteins
/
Neoplasm Proteins
Type of study:
Risk_factors_studies
Limits:
Humans
Language:
En
Journal:
Mol Immunol
Year:
2007
Document type:
Article
Affiliation country:
Spain
Country of publication:
United kingdom