title: CD8(+) T-cell selection, function, and death in the primary immune response in vivo.
abstract: The primary immune response to Epstein Barr virus (EBV) is characterized by striking proliferation of EBV-specific CD8(+) T cells. In this study we have investigated the clonal composition and functional properties of the cells mediating this primary response and have analyzed the mechanisms that control the downregulation of the primary response and the selection of memory cells. We show that massively expanded T-cell clones often dominate the primary antigen-specific T-cell response. Despite the enormous extent of expansion, the virus-specific T cells express high levels of intracellular perforin and are potently cytotoxic. They are, however, functionally heterogeneous in their ability to secrete proinflammatory cytokines, with subpopulations of the antigen-specific T cells being hyporesponsive. The primary response is closely regulated, and the majority of cells are programmed to die via a cytokine-rescuable pathway, leaving only small populations of memory T cells surviving. Comparison of the clonal composition of primary and memory responses in vivo shows that the clones that dominate the primary response are relatively heavily culled during the downregulation of the primary response and the establishment of T-cell memory.
authors.affiliation: MRC Human Immunology Unit, Institute of Molecular Medicine, Headington, Oxford, United Kingdom.
authors.forename: M F
authors.initials: MF
authors.lastname: Callan
authors.forename: C
authors.initials: C
authors.lastname: Fazou
authors.forename: H
authors.initials: H
authors.lastname: Yang
authors.forename: T
authors.initials: T
authors.lastname: Rostron
authors.forename: K
authors.initials: K
authors.lastname: Poon
authors.forename: C
authors.initials: C
authors.lastname: Hatton
authors.forename: A J
authors.initials: AJ
authors.lastname: McMichael
mesh_terms: D000956:Antigens, Viral / Q000276:immunology; D017209:Apoptosis / Q000276:immunology*; D005075:Biological Evolution; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D003602:Cytotoxicity, Immunologic / Q000276:immunology; D004268:DNA-Binding Proteins / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D004854:Herpesvirus 4, Human / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology; D007244:Infectious Mononucleosis / Q000276:immunology*; D007371:Interferon-gamma; D009842:Oligopeptides / Q000276:immunology; D010750:Phosphoproteins / Q000276:immunology; D015534:Trans-Activators / Q000276:immunology; D014764:Viral Proteins / Q000276:immunology
chemical_list: D000956:Antigens, Viral; C063676:BZLF1 protein, Herpesvirus 4, Human; D004268:DNA-Binding Proteins; D018984:Epitopes, T-Lymphocyte; D009842:Oligopeptides; D010750:Phosphoproteins; C090236:SM protein, Human herpesvirus 4; D015534:Trans-Activators; D014764:Viral Proteins; C403195:glycyl-leucyl-cysteinyl-threonyl-leucyl-valyl-alanyl-methionyl-leucine; D007371:Interferon-gamma