title: Soluble MHC-peptide complexes induce rapid death of CD8+ CTL.
abstract: Soluble MHC-peptide (pMHC) complexes, commonly referred to as tetramers, are widely used to enumerate and to isolate Ag-specific CD8(+) CTL. It has been noted that such complexes, as well as microsphere- or cell-associated pMHC molecules compromise the functional integrity of CTL, e.g., by inducing apoptosis of CTL, which limits their usefulness for T cell sorting or cloning. By testing well-defined soluble pMHC complexes containing linkers of different length and valence, we find that complexes comprising short linkers (i.e., short pMHC-pMHC distances), but not those containing long linkers, induce rapid death of CTL. This cell death relies on CTL activation, the coreceptor CD8 and cytoskeleton integrity, but is not dependent on death receptors (i.e., Fas, TNFR1, and TRAILR2) or caspases. Within minutes of CTL exposure to pMHC complexes, reactive oxygen species emerged and mitochondrial membrane depolarized, which is reminiscent of caspase-independent T cell death. The morphological changes induced during this rapid CTL death are characteristic of programmed necrosis and not apoptosis. Thus, soluble pMHC complexes containing long linkers are recommended to prevent T cell death, whereas those containing short linkers can be used to eliminate Ag-specific CTL.
authors.affiliation: Ludwig Institute for Cancer Research, Lausanne Branch, Epalinges, Switzerland.
authors.forename: Marek
authors.initials: M
authors.lastname: Cebecauer
authors.forename: Philippe
authors.initials: P
authors.lastname: Guillaume
authors.forename: Pavel
authors.initials: P
authors.lastname: Hozák
authors.forename: Silke
authors.initials: S
authors.lastname: Mark
authors.forename: Helen
authors.initials: H
authors.lastname: Everett
authors.forename: Pascal
authors.initials: P
authors.lastname: Schneider
authors.forename: Immanuel F
authors.initials: IF
authors.lastname: Luescher
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology*; D002478:Cells, Cultured; D002999:Clone Cells; D016572:Cyclosporine / Q000494:pharmacology; D003602:Cytotoxicity, Immunologic / Q000187:drug effects / Q000276:immunology*; D019281:Dimerization; D004306:Dose-Response Relationship, Immunologic; D006131:Growth Inhibitors / Q000502:physiology*; D006183:H-2 Antigens / Q000502:physiology*; D007700:Kinetics; D008564:Membrane Potentials / Q000502:physiology; D008928:Mitochondria / Q000378:metabolism / Q000502:physiology; D009336:Necrosis; D009842:Oligopeptides / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D016192:Resting Phase, Cell Cycle / Q000187:drug effects / Q000276:immunology; D012995:Solubility; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D015091:beta-Alanine / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D006131:Growth Inhibitors; D006183:H-2 Antigens; D009842:Oligopeptides; D017382:Reactive Oxygen Species; D015091:beta-Alanine; D016572:Cyclosporine; C011757:2,3-diaminopropionic acid