title: Different programs of activation-induced cell death are triggered in mature activated CTL by immunogenic and partially agonistic peptide ligands.
abstract: Activation-induced cell death (AICD) of mature T cells plays an important role in the control of immune homeostasis and peripheral tolerance. TNFRs and Fas have been implicated in the induction of AICD. However, these molecules were shown to be dispensable, at least in some experimental systems, for downsizing of Ag-induced T cell expansions and development of tolerance in vivo. The conditions of T cell activation leading to T cell deletion in a death receptor-independent manner are not well characterized. Here we show that human CTLs die through a death receptor-independent apoptotic program upon triggering with a partially agonistic peptide ligand. This apoptotic process exhibits some features of T cell death due to lymphokine deprivation and is blocked by exogenous IL-2. Our data demonstrate that engagement of TCR by MHC-peptide complexes can trigger diverse apoptotic programs of AICD and that the choice between these programs is determined by the agonistic potency of MHC-peptide ligand.
authors.affiliation: Microbiology and Tumor Biology Center, Karolinska Institutet, Stockholm, Sweden.
authors.forename: C H
authors.initials: CH
authors.lastname: Wei
authors.forename: H
authors.initials: H
authors.lastname: Yagita
authors.forename: M G
authors.initials: MG
authors.lastname: Masucci
authors.forename: V
authors.initials: V
authors.lastname: Levitsky
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology*; D016923:Cell Death / Q000187:drug effects / Q000276:immunology; D002454:Cell Differentiation / Q000187:drug effects / Q000276:immunology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000276:immunology; D002999:Clone Cells; D016572:Cyclosporine / Q000494:pharmacology; D019309:Epstein-Barr Virus Nuclear Antigens / Q000276:immunology / Q000378:metabolism; D053222:Fas Ligand Protein; D015234:HLA-A Antigens / Q000276:immunology; D059870:HLA-A11 Antigen; D006801:Humans; D007376:Interleukin-2 / Q000037:antagonists & inhibitors / Q000494:pharmacology; D007700:Kinetics; D008024:Ligands; D008213:Lymphocyte Activation / Q000187:drug effects; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D051379:Mice; D010446:Peptide Fragments / Q000819:agonists* / Q000276:immunology* / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology* / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000276:immunology; D051020:bcl-X Protein; D019014:fas Receptor / Q000378:metabolism
chemical_list: C494811:BCL2L1 protein, human; C494812:Bcl2l1 protein, mouse; D019309:Epstein-Barr Virus Nuclear Antigens; C505661:FASLG protein, human; D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D015234:HLA-A Antigens; D059870:HLA-A11 Antigen; D007376:Interleukin-2; D008024:Ligands; D008562:Membrane Glycoproteins; D010446:Peptide Fragments; D019253:Proto-Oncogene Proteins c-bcl-2; D051020:bcl-X Protein; D019014:fas Receptor; D016572:Cyclosporine