MINI REVIEW ARTICLE
Front. Immunol., 06 August 2013 | doi: 10.3389/fimmu.2013.00231
The impact of aging on regulatory T-cells
- 1Department of Rheumatology and Immunology, Medical University Graz, Graz, Austria
- 2Department of Internal Medicine, General Hospital Kufstein, Kufstein, Austria
Age-related deviations of the immune system contribute to a higher likelihood of infections, cancer, and autoimmunity in the elderly. Senescence of T-lymphocytes is characterized by phenotypical and functional changes including the loss of characteristic T-cell surface markers, while an increase of stimulatory receptors, cytotoxicity as well as resistance against apoptosis is observed. One of the key mediators of immune regulation are naturally occurring regulatory T-cells (Tregs). Tregsexpress high levels of CD25 and the intracellular protein forkhead box P3; they exert their suppressive functions in contact-dependent as well as contact-independent manners. Quantitative and qualitative defects of Tregswere observed in patients with autoimmune diseases. Increased Tregactivity was shown to suppress anti-tumor and anti-infection immunity. The effect of aging on Tregs, and the possible contribution of age-related changes of the Treg pool to the pathophysiology of diseases in the elderly are still poorly understood. Treg homeostasis depends on an intact thymic function and current data suggest that conversion of non-regulatory T-cells into Tregs as well as peripheral expansion of existing Tregscompensates for thymic involution after puberty to maintain constant Tregnumbers. In the conventional T-cell subset, peripheral proliferation of T-cells is associated with replicative senescence leading to phenotypical and functional changes. For Tregs, different developmental stages were also described; however, replicative senescence of Tregs has not been observed yet.
Keywords: FOXP3, regulatory T-lymphocyte, aging, cellular senescence, thymus, suppressor cells
Citation: Fessler J, Ficjan A, Duftner C and Dejaco C (2013) The impact of aging on regulatory T-cells. Front. Immunol. 4:231. doi: 10.3389/fimmu.2013.00231
Received: 28 March 2013; Accepted: 22 July 2013;
Published online: 06 August 2013.
Published online: 06 August 2013.
Edited by:
Dietmar Herndler-Brandstetter, Yale University School of Medicine, USA
Reviewed by:
Nikolai Petrovsky, Flinders Medical Centre, AustraliaTyler Curiel, University of Texas Health Science Center at San Antonio, USA
Copyright: © 2013 Fessler, Ficjan, Duftner and Dejaco. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Christian Dejaco, Department of Rheumatology and Immunology, Medical University Graz, Auenbruggerplatz 15, A-8036 Graz, Austria e-mail: christian.dejaco@gmx.net
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