title: Post-thymic regulation of CD5 levels in human memory T cells is inversely associated with the strength of responsiveness to interleukin-15.
abstract: Immunologic memory is a critical feature of the adaptive immune system to fight recurrent infections. However, the mechanisms that shape the composition and function of the human memory T-cell pool remain incompletely understood. We here demonstrate that post-thymic human T-cell differentiation was associated with the downregulation, but not loss, of the inhibitory molecule CD5. The sensitivity of human CD8(+) and CD4(+) memory T cells to interleukin (IL)-15 was inversely associated with the level of CD5 expression. CD5 expression was downregulated by IL-15-mediated signaling in vitro and CD5(lo) memory T cells accumulated in the bone marrow. Persistent antigenic stimulation, as in the case of cytomegalovirus infection and rheumatoid arthritis (RA), was also associated with an increased number of CD5(lo) memory T cells. In conclusion, CD5 may be a useful marker to identify memory T-cell subsets with distinct responsiveness to the homeostatic cytokine IL-15.
authors.affiliation: Institute for Biomedical Aging Research, Austrian Academy of Sciences, Innsbruck, Austria. dietmar.herndler-brandstetter@oeaw.ac.at
authors.forename: Dietmar
authors.initials: D
authors.lastname: Herndler-Brandstetter
authors.forename: Stefan
authors.initials: S
authors.lastname: Brunner
authors.forename: Daniela
authors.initials: D
authors.lastname: Weiskopf
authors.forename: Ruth
authors.initials: R
authors.lastname: van Rijn
authors.forename: Katja
authors.initials: K
authors.lastname: Landgraf
authors.forename: Christian
authors.initials: C
authors.lastname: Dejaco
authors.forename: Christina
authors.initials: C
authors.lastname: Duftner
authors.forename: Michael
authors.initials: M
authors.lastname: Schirmer
authors.forename: Frank
authors.initials: F
authors.lastname: Kloss
authors.forename: Robert
authors.initials: R
authors.lastname: Gassner
authors.forename: Günter
authors.initials: G
authors.lastname: Lepperdinger
authors.forename: Beatrix
authors.initials: B
authors.lastname: Grubeck-Loebenstein
mesh_terms: D001172:Arthritis, Rheumatoid / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D018956:CD5 Antigens / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D002454:Cell Differentiation; D002478:Cells, Cultured; D003587:Cytomegalovirus / Q000254:growth & development; D003586:Cytomegalovirus Infections / Q000276:immunology / Q000821:virology; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D015870:Gene Expression / Q000276:immunology; D006801:Humans; D007156:Immunologic Memory; D019409:Interleukin-15 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015398:Signal Transduction / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*
chemical_list: D018956:CD5 Antigens; D019409:Interleukin-15