The dynamic co-evolution of memory and regulatory CD4+ T cells in the periphery

Department of Immunology and Molecular Pathology, Division of Infection and Immunity, Windeyer Institute of Medical Sciences, University College London, London W1T 4JF, UK.
Nature reviews. Immunology (Impact Factor: 34.99). 04/2007; 7(3):231-7. DOI: 10.1038/nri2037
Source: PubMed


Whereas memory T cells are required to maintain immunity, regulatory T cells have to keep the immune system in check to prevent excessive inflammation and/or autoimmunity. Both cell types must be present during the lifetime of the organism. However, it is not clear whether both subsets are regulated in tandem or independently of each other, especially because thymic involution severely restricts the production of T-cell populations during ageing. In this Opinion article, we discuss recent evidence in both mice and humans that supports the hypothesis that some CD4(+)CD25(+)FOXP3(+)regulatory T cells can differentiate from rapidly proliferating memory T cells in the periphery.

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Available from: Milica Vukmanovic-Stejic, Mar 16, 2015
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    • "Cytokine IL-17 has proinflammatory activity and characterizes the type-Th17 response [23] [24]; it has been described to induce inflammation in autoimmune diseases and acute graft rejection. In contrast, Treg cells induce immunoregulation and tolerance by inhibiting cytokine production and proliferation in T CD4 + and CD8 + cells, immunoglobulin production by B cells, the cytotoxic activity of natural-killer cells, and the maturation of dendritic cells, which results in tolerance induction [18] [25] [26]. "
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    • "This result indicated the possibility that impaired thymic export contributes to Treg cell defects in this patient population. However, nTreg cells can proliferate after thymic output while retaining their naïve phenotype [37]. CD31 has been used as a direct marker of thymic output and enabled the discrimination of recent thymic emigrant (RTE) Treg cells from peripherally expanded nTreg cells [38]. "
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    • "Regulatory T cells are thought to derive either as a separate lineage from the thymus that are present at birth and often termed natural regulatory T cells or, are derived from previously activated T cells that after a number of cell divisions either gain, or can be induced, to have regulatory functions. These cells are often termed adaptive or induced regulatory T cells (Akbar et al., 2007). Previous work by our group and others has shown that in children with ASD there is a decrease in the regulatory cytokine TGFb1 that is produced by different types of regulatory T cells, and decreases in the frequencies of the CD3 + IL-10 + T cell subset that may reflect changes in the ability of specific types of regulatory T cells to control immune responses in ASD (Ashwood et al., 2004, 2006, 2008; Jyonouchi et al., 2001; Molloy et al., 2005; Okada et al., 2007). "
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