title: The frequency of regulatory CD3+CD8+CD28- CD25+ T lymphocytes in human peripheral blood increases with age.
abstract: Aging is commonly associated with immune deficiency and dysregulation. The aging of the immune system involves a progressive reduction in naïve T cell output associated with thymic involution and peripheral expansion of oligoclonal memory T cells. We have investigated frequency, phenotype, and function of CD3+CD8+CD28(-)CD25+ T cells in healthy volunteers over a wide age range. We demonstrate that the frequency of CD3+CD8+CD28(-)CD25+ T cells in healthy volunteers increases with age. Peripheral CD3+CD8+CD28(-)CD25+ T cells share phenotypic and functional features with CD3+CD4+CD25+ regulatory T cells (Tregs): In particular, they strongly express CTLA-4 and forkhead box P3. We observed that in vitro, functional titration assays of CD3+CD8+CD28(-)CD25+ T cells show equivalent regulatory function in young and elderly donors, with suppression of proliferation and cytokine production in response to polyclonal T cell stimulation. Finally, CD3+CD8+CD28(-)CD25+ T cells seem to specifically express the CD122 receptor. Altogether, these observations demonstrate an increase in peripheral blood CD8+ Tregs associated with aging.
authors.affiliation: Department of Experimental Medicine, Section of Human Anatomy, University of Genova, Genova, Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: Simone
authors.forename: Anna
authors.initials: A
authors.lastname: Zicca
authors.forename: Daniele
authors.initials: D
authors.lastname: Saverino
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D018106:CD28 Antigens / Q000276:immunology*; D017252:CD3 Complex / Q000276:immunology*; D015704:CD4 Antigens / Q000276:immunology*; D049109:Cell Proliferation; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D008875:Middle Aged; D010641:Phenotype; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D018106:CD28 Antigens; D017252:CD3 Complex; D015704:CD4 Antigens; D053645:Interleukin-2 Receptor alpha Subunit