title: CD28 expression in T cell aging and human longevity.
abstract: Functional decrements of the immune system have a major contribution to aging and age-related diseases. Here, we further characterize the decline in proportion of CD28-positive T cells previously identified in centenarians. Cohorts of 97 centenarians, 40 subjects aged 70-90 (ELD group), and 40 young adults (under age 40) were phenotyped for T cell surface expression of CD28, CD4, and CD8 antigens. The significant decline in T cells expressing CD28 (p < 10(-4) for comparisons between adults and either ELD or centenarians) affects preferentially the CD8+ subset of T cells. This decline accounts largely for the age-related diminution of T cell responsiveness to mitogenic signals. CD28 expression is modulated in T cell cultures in a growth-related fashion and this modulation is dampened in cultures from centenarians. We propose that the decrease in CD28 expression reflects a compensatory adaptation of the immune system during aging in the face of chronic stimulation.
authors.affiliation: Centre d'Etude du Polymorphisme Humain, Paris, France.
authors.forename: N
authors.initials: N
authors.lastname: Boucher
authors.forename: T
authors.initials: T
authors.lastname: Dufeu-Duchesne
authors.forename: E
authors.initials: E
authors.lastname: Vicaut
authors.forename: D
authors.initials: D
authors.lastname: Farge
authors.forename: R B
authors.initials: RB
authors.lastname: Effros
authors.forename: F
authors.initials: F
authors.lastname: Schächter
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001773:Blood Cells / Q000276:immunology; D018106:CD28 Antigens / Q000032:analysis*; D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000502:physiology; D006801:Humans; D008136:Longevity / Q000502:physiology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000502:physiology*
chemical_list: D018106:CD28 Antigens