Premium
Down‐regulation of normal human T cell blast activation: roles of APO2L/TRAIL, FasL, and c‐ FLIP, Bim, or Bcl‐x isoform expression
Author(s) -
Bosque Alberto,
Pardo Julián,
MartínezLorenzo Mª José,
Iturralde María,
Marzo Isabel,
Piñeiro Andrés,
Alava Mª Angeles,
Naval Javier,
Anel Alberto
Publication year - 2005
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1189/jlb.0904514
Subject(s) - fas ligand , biology , programmed cell death , apoptosis , fas receptor , cytotoxic t cell , microbiology and biotechnology , t cell , tumor necrosis factor alpha , cd3 , cancer research , immunology , antigen , immune system , biochemistry , cd8 , in vitro
A systematic study was undertaken to characterize the role of APO 2 ligand/tumor necrosis factor‐related apoptosis‐inducing ligand (APO2L/TRAIL) and Fas ligand (FasL) together with the expression of several anti‐ or proapoptotic proteins in the down‐regulation of normal human T cell responses. We have observed for the first time that the higher sensitivity of normal human T cell blasts to apoptosis and activation‐induced cell death (AICD) as compared with naïve T cells correlates with the increased expression of Bcl‐x short (Bcl‐x S ) and Bim. T cell blasts die in the absence of interleukin 2 (IL‐2) with no additional effect of death receptor ligation. In the presence of IL‐2, recombinant APO2L/TRAIL or cytotoxic anti‐Fas monoclonal antibodies induce rather inhibition of IL‐2‐dependent growth and not cell death on normal human T cell blasts. This observation is of physiological relevance, as supernatants from T cell blasts, pulse‐stimulated with phytohemagglutinin (PHA) or through CD3 or CD59 ligation and containing bioactive APO2L/TRAIL and/or FasL expressed on microvesicles or direct CD3 or CD59 ligation, had the same effect. Cell death was only observed in the presence of cycloheximide or after a pulse through CD3 or CD59, correlating with a net reduction in cellular Fas‐associated death domain‐like IL‐1β‐converting enzyme‐inhibitory protein long (c‐FLIP L ) and c‐FLIP S expression. We also show that death receptor and free radical generation contribute, at least partially, to AICD induced by PHA and also to the inhibition of IL‐2‐dependent cell growth by CD3 or CD59 ligation. Finally, we have also shown that T cell blasts surviving PHA‐induced AICD are memory CD44 high cells with increased c‐FLIP S and Bcl‐x L expression.