title: Large numbers of dysfunctional CD8+ T lymphocytes bearing receptors for a single dominant CMV epitope in the very old.
abstract: Longitudinal studies suggest that a set of immune parameters including high percentages of peripheral CD8+, CD28-, CD57+ T lymphocytes, low CD4 and B cell counts, and poor T cell proliferative responses to mitogens is associated with decreased remaining longevity in the free-living very elderly (> 85 years). This combination of immune parameters was also significantly associated with an inverted CD4/CD8 ratio and cytomegalovirus seropositivity. Here, using tetramer technology, we show markedly increased numbers of CD8+ T cells bearing receptors for one single CMV epitope in the very elderly. Moreover, the fraction of these tetramer-reactive cells secreting interferon-gamma after specific antigenic stimulation was significantly lower in the old than in the young, as was the percentage of CD28-positive cells in this population. Therefore, we conclude that marked expansions of CMV-specific CD8+ T cells have occurred and that the obsession of a large fraction of the entire CD8+ T cell subset with one single viral epitope may contribute to the increased incidence of infectious disease in the elderly by shrinking the T cell repertoire available for responses to other antigens.
authors.affiliation: Tuebingen Ageing and Tumour Immunology Group, Section for Transplantation-Immunology and Immunohematology, University of Tübingen, Tübingen, Germany. qin.ouyang@uni-tuebingen.de
authors.forename: Qin
authors.initials: Q
authors.lastname: Ouyang
authors.forename: Wolfgang M
authors.initials: WM
authors.lastname: Wagner
authors.forename: Anders
authors.initials: A
authors.lastname: Wikby
authors.forename: Steffen
authors.initials: S
authors.lastname: Walter
authors.forename: Geraldine
authors.initials: G
authors.lastname: Aubert
authors.forename: Anthony I
authors.initials: AI
authors.lastname: Dodi
authors.forename: Paul
authors.initials: P
authors.lastname: Travers
authors.forename: Graham
authors.initials: G
authors.lastname: Pawelec
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology*; D015415:Biomarkers; D016516:CD4-CD8 Ratio; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D003587:Cytomegalovirus / Q000276:immunology*; D003586:Cytomegalovirus Infections / Q000276:immunology*; D000939:Epitopes / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007371:Interferon-gamma / Q000378:metabolism; D008137:Longitudinal Studies; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D011948:Receptors, Antigen, T-Cell / Q000032:analysis*; D016176:T-Lymphocyte Subsets / Q000276:immunology
chemical_list: D015415:Biomarkers; D000939:Epitopes; D007074:Immunoglobulin G; D011948:Receptors, Antigen, T-Cell; D007371:Interferon-gamma