title: Accelerated age-dependent transition of human regulatory T cells to effector memory phenotype.
abstract: We and others recently described a method for isolating viable forkhead boxp3 (FoxP3(+)) T regulatory cells (Tregs) by means of the surface phenotype CD4(+)CD127(lo)CD25(+). In this study, we used the new strategy to measure Treg numbers, phenotype and function at different ages. Mean percentages of CD4(+)CD127(lo)CD25(+) Tregs increased only slightly throughout life, from 6.10% in cord blood to 7.22% in PBMC from adults between 20 and 25 years and 7.50% in PBMC from adults over the age of 60. In all age groups, a higher proportion of Tregs had acquired a CD45RA(-) memory phenotype compared with CD4(+)Foxp3(-) conventional T cells. This increase was entirely attributable to increased Tregs with an effector memory phenotype, whereas central memory phenotype cells were comparably represented within the Treg and conventional CD4(+) T-cell populations. Expression of CD95 also differed between Tregs and conventional CD4(+) T cells at all ages. However there was no difference in the suppressive capacity of the different naive and memory Treg subsets. These results suggest that, compared with their conventional CD4(+) T-cell counterparts, Tregs undergo preferential differentiation from a naive to an effector memory phenotype, driven by their specificity for self- rather than foreign antigen. However, number and function are remarkably stable throughout life.
authors.affiliation: Discipline of Paediatrics, Nepean Clinical School, University of Sydney, Penrith 2751, New South Wales, Australia.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Santner-Nanan
authors.forename: Nabila
authors.initials: N
authors.lastname: Seddiki
authors.forename: Erhua
authors.initials: E
authors.lastname: Zhu
authors.forename: Verena
authors.initials: V
authors.lastname: Quent
authors.forename: Anthony
authors.initials: A
authors.lastname: Kelleher
authors.forename: Barbara
authors.initials: B
authors.lastname: Fazekas de St Groth
authors.forename: Ralph
authors.initials: R
authors.lastname: Nanan
mesh_terms: D000328:Adult; D000367:Age Factors; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D005312:Fetal Blood / Q000166:cytology; D051858:Forkhead Transcription Factors / Q000276:immunology; D005786:Gene Expression Regulation; D006801:Humans; D007156:Immunologic Memory / Q000235:genetics / Q000276:immunology; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology; D053699:Interleukin-7 Receptor alpha Subunit / Q000276:immunology; D008875:Middle Aged; D010641:Phenotype; D016176:T-Lymphocyte Subsets / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D055815:Young Adult
chemical_list: C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D053645:Interleukin-2 Receptor alpha Subunit; D053699:Interleukin-7 Receptor alpha Subunit