Post-thymic regulation of CD5 levels in human memory T cells is inversely associated with the strength of responsiveness to interleukin-15

• Published in: Human immunology 2011-08, Vol.72 (8), p.627-631
• Main Authors: Herndler-Brandstetter, Dietmar, Brunner, Stefan, Weiskopf, Daniela, van Rijn, Ruth, Landgraf, Katja, Dejaco, Christian, Duftner, Christina, Schirmer, Michael, Kloss, Frank, Gassner, Robert, Lepperdinger, Günter, Grubeck-Loebenstein, Beatrix
• Format: Article
• Language: English
• Subjects: Allergy and Immunology; Arthritis, Rheumatoid - immunology; Bone marrow; CD4-Positive T-Lymphocytes - cytology; CD4-Positive T-Lymphocytes - immunology; CD5; CD5 Antigens - genetics; CD5 Antigens - immunology; CD5 Antigens - metabolism; CD8-Positive T-Lymphocytes - cytology; CD8-Positive T-Lymphocytes - immunology; Cell Differentiation; Cells, Cultured; Cytomegalovirus; Cytomegalovirus - growth & development; Cytomegalovirus Infections - immunology; Cytomegalovirus Infections - virology; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; Gene Expression - immunology; Human; Humans; Immunologic Memory; Interleukin-15; Interleukin-15 - genetics; Interleukin-15 - immunology; Interleukin-15 - metabolism; Memory T cell; Rheumatoid arthritis; Signal Transduction - immunology; T-Lymphocyte Subsets - cytology; T-Lymphocyte Subsets - immunology; T-Lymphocytes - immunology; T-Lymphocytes - metabolism; Thymus Gland - cytology; Thymus Gland - immunology
• ISSN: 0198-8859; 1879-1166
• DOI: 10.1016/j.humimm.2011.03.028

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 CD5lo 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 CD5lo 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.