Document Detail


Cathepsin-dependent apoptosis triggered by supraoptimal activation of T lymphocytes: a possible mechanism of high dose tolerance.
MedLine Citation:
PMID:  15100281     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
High doses of Ag can paradoxically suppress immune responses in vivo. This Ag-specific unresponsiveness (termed high dose tolerance) involves extrathymic mechanisms in mature T lymphocytes. To investigate these mechanisms, we used the in vitro model of PBL activated with anti-CD3 or PHA. In these conditions, increasing mitogen concentrations resulted in a reduction of the proliferative response, associated with an increased percentage of apoptotic cells. Apoptosis did not require prior exposure to IL-2, it was not the consequence of CD178/CD95 or TNF/TNFR interactions, and was therefore clearly distinct from activation-induced cell death. Although the pan-caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (zVAD-fmk) decreased DNA fragmentation, cytochrome c release and caspase-9 and caspase-3 activation were not implicated, suggesting that this apoptosis did not primarily involve the intrinsic mitochondrial pathway. E64d, a cysteine protease inhibitor, as well as specific inhibitors of cathepsin B and cathepsin L conferred protection. We further demonstrated that cathepsin B and cathepsin L were released from the lysosomes and catalytically active in the cytosol. Release of cathepsin B and cathepsin L was the consequence of lysosomal membrane permeabilization without complete disruption of the cytosol-lysosome pH gradient. These results demonstrate a role for cathepsins in supraoptimal activation-induced apoptosis in vitro and suggest their possible participation in high dose tolerance in vivo.
Authors:
Marie-Cécile Michallet; Frédéric Saltel; Monique Flacher; Jean-Pierre Revillard; Laurent Genestier
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of immunology (Baltimore, Md. : 1950)     Volume:  172     ISSN:  0022-1767     ISO Abbreviation:  J. Immunol.     Publication Date:  2004 May 
Date Detail:
Created Date:  2004-04-21     Completed Date:  2004-08-17     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  2985117R     Medline TA:  J Immunol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  5405-14     Citation Subset:  AIM; IM    
Affiliation:
Laboratoire d'Immunopharmacologie, Institut National de la Santé et de la Recherche Médicale Unité 503, Centre d'Etudes et de Recherche en Virologie et Immunologie, Lyon, France.
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Chloromethyl Ketones / pharmacology
Antigens, CD28 / pharmacology
Apoptosis / immunology*
Caspases / antagonists & inhibitors
Catalysis
Cathepsin B / antagonists & inhibitors,  physiology*,  secretion
Cathepsin L
Cathepsins / antagonists & inhibitors,  physiology*,  secretion
Cell Death / immunology
Cell Differentiation / immunology
Cells, Cultured
Cysteine Endopeptidases
Cysteine Proteinase Inhibitors / pharmacology
Cytochromes c / secretion
Cytosol / enzymology,  immunology,  secretion
DNA Fragmentation / drug effects,  immunology
Dose-Response Relationship, Immunologic
G1 Phase / immunology
Humans
Intracellular Membranes / enzymology,  immunology
Lymphocyte Activation / immunology*
Lysosomes / enzymology
Muromonab-CD3 / pharmacology
Permeability
S Phase / immunology
T-Lymphocytes / cytology,  enzymology*,  immunology*,  secretion
Tetradecanoylphorbol Acetate / pharmacology
Chemical
Reg. No./Substance:
0/Amino Acid Chloromethyl Ketones; 0/Antigens, CD28; 0/Cysteine Proteinase Inhibitors; 0/Muromonab-CD3; 0/benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; 16561-29-8/Tetradecanoylphorbol Acetate; 9007-43-6/Cytochromes c; EC 3.4.-/Cathepsins; EC 3.4.22.-/Caspases; EC 3.4.22.-/Cysteine Endopeptidases; EC 3.4.22.1/Cathepsin B; EC 3.4.22.15/CTSL1 protein, human; EC 3.4.22.15/Cathepsin L

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