Key Points
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Regulatory T (TReg) cells are a distinct lineage of CD4+ T cells that differentiate in response to agonist self antigens in the thymus and to non-pathogenic foreign antigens in the periphery.
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The involvement of T cell receptor (TCR) signalling modules that have opposing activities in T cell lineage specification favours a TReg cell repertoire that, in general, reacts to low-abundance, high-affinity antigens.
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Compared with ubiquitous antigens, low-abundance, high-affinity antigens will probably induce inefficient clonal deletion of T cells, and thus the existence of these antigens justifies the necessity of TReg cell-mediated dominant immune tolerance.
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Depending on the expression of activation markers, mature TReg cells can be divided into resting and activated TReg cell subsets, and these discrete populations probably accompany conventional T cells to control their activation and effector functions in secondary lymphoid organs and target tissues.
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Distinct TCR signalling modules are selectively involved in the control of trafficking, maintenance and suppressive activities of resting and activated TReg cells.
Abstract
Regulatory T cells (TReg cells), a specialized T cell lineage, have a pivotal function in the control of self tolerance and inflammatory responses. Recent studies have revealed a discrete mode of T cell receptor (TCR) signalling that regulates TReg cell differentiation, maintenance and function and that affects gene expression, metabolism, cell adhesion and migration of these cells. Here, we discuss the emerging understanding of TCR-guided differentiation of TReg cells in the context of their function in health and disease.
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References
Burnet, F. M. The Clonal Selection Theory of Acquired Immunity (Vanderbilt Univ. Press, 1959).
Josefowicz, S. Z., Lu, L. F. & Rudensky, A. Y. Regulatory T cells: mechanisms of differentiation and function. Annu. Rev. Immunol. 30, 531–564 (2012).
Sakaguchi, S., Yamaguchi, T., Nomura, T. & Ono, M. Regulatory T cells and immune tolerance. Cell 133, 775–787 (2008).
Nishizuka, Y. Thymus and reproduction: sex-linked dysgnesia of the gonad after neonatal thymectomy in mice. Science 166, 753–755 (1969).
Sakaguchi, S., Fukuma, K., Kuribayashi, K. & Masuda, T. Organ-specific autoimmune diseases induced in mice by elimination of T cell subset. I. Evidence for the active participation of T cells in natural self-tolerance; deficit of a T cell subset as a possible cause of autoimmune disease. J. Exp. Med. 161, 72–87 (1985).
Takahashi, T. et al. Immunologic self-tolerance maintained by CD25+CD4+ regulatory T cells constitutively expressing cytotoxic T lymphocyte-associated antigen 4. J. Exp. Med. 192, 303–310 (2000).
Sakaguchi, S., Sakaguchi, N., Asano, M., Itoh, M. & Toda, M. Immunologic self-tolerance maintained by activated T cells expressing IL-2 receptor alpha-chains (CD25). Breakdown of a single mechanism of self-tolerance causes various autoimmune diseases. J. Immunol. 155, 1151–1164 (1995).
Powrie, F., Leach, M. W., Mauze, S., Caddle, L. B. & Coffman, R. L. Phenotypically distinct subsets of CD4+ T cells induce or protect from chronic intestinal inflammation in C. B-17 SCID mice. Int. Immunol. 5, 1461–1471 (1993).
Morrissey, P. J., Charrier, K., Braddy, S., Liggitt, D. & Watson, J. D. CD4+ T cells that express high levels of CD45RB induce wasting disease when transferred into congenic severe combined immunodeficient mice. Disease development is prevented by cotransfer of purified CD4+ T cells. J. Exp. Med. 178, 237–244 (1993).
Hori, S., Nomura, T. & Sakaguchi, S. Control of regulatory T cell development by the transcription factor Foxp3. Science 299, 1057–1061 (2003).
Fontenot, J. D., Gavin, M. A. & Rudensky, A. Y. Foxp3 programs the development and function of CD4+CD25+ regulatory T cells. Nat. Immunol. 4, 330–336 (2003).
Khattri, R., Cox, T., Yasayko, S.-A. & Ramsdell, F. An essential role for Scurfin in CD4+CD25+ T regulatory cells. Nat. Immunol. 4, 337–342 (2003).
Fontenot, J. D. et al. Regulatory T cell lineage specification by the forkhead transcription factor Foxp3. Immunity 22, 329–341 (2005).
Gavin, M. A. et al. Foxp3-dependent programme of regulatory T-cell differentiation. Nature 445, 771–775 (2007).
Lin, W. et al. Regulatory T cell development in the absence of functional Foxp3. Nat. Immunol. 8, 359–368 (2007).
Luo, C. T. & Li, M. O. Transcriptional control of regulatory T cell development and function. Trends Immunol. 34, 531–539 (2013).
Moran, A. E. et al. T cell receptor signal strength in Treg and iNKT cell development demonstrated by a novel fluorescent reporter mouse. J. Exp. Med. 208, 1279–1289 (2011).
Hsieh, C. S., Zheng, Y., Liang, Y., Fontenot, J. D. & Rudensky, A. Y. An intersection between the self-reactive regulatory and nonregulatory T cell receptor repertoires. Nat. Immunol. 7, 401–410 (2006).
Lafaille, J. J., Nagashima, K., Katsuki, M. & Tonegawa, S. High incidence of spontaneous autoimmune encephalomyelitis in immunodeficient anti-myelin basic protein T cell receptor transgenic mice. Cell 78, 399–408 (1994).
Jordan, M. S. et al. Thymic selection of CD4+CD25+ regulatory T cells induced by an agonist self-peptide. Nat. Immunol. 2, 301–306 (2001).
Apostolou, I., Sarukhan, A., Klein, L. & von Boehmer, H. Origin of regulatory T cells with known specificity for antigen. Nat. Immunol. 3, 756–763 (2002).
Cozzo Picca, C. et al. CD4+CD25+Foxp3+ regulatory T cell formation requires more specific recognition of a self-peptide than thymocyte deletion. Proc. Natl Acad. Sci. USA 108, 14890–14895 (2011).
Lee, H. M., Bautista, J. L., Scott-Browne, J., Mohan, J. F. & Hsieh, C. S. A broad range of self-reactivity drives thymic regulatory T cell selection to limit responses to self. Immunity 37, 475–486 (2012).
Paiva, R. S. et al. Recent thymic emigrants are the preferential precursors of regulatory T cells differentiated in the periphery. Proc. Natl Acad. Sci. USA 110, 6494–6499 (2013).
Apostolou, I. & von Boehmer, H. In vivo instruction of suppressor commitment in naive T cells. J. Exp. Med. 199, 1401–1408 (2004).
Kretschmer, K. et al. Inducing and expanding regulatory T cell populations by foreign antigen. Nat. Immunol. 6, 1219–1227 (2005).
Gottschalk, R. A., Corse, E. & Allison, J. P. TCR ligand density and affinity determine peripheral induction of Foxp3 in vivo. J. Exp. Med. 207, 1701–1711 (2010).
Daley, S. R., Hu, D. Y. & Goodnow, C. C. Helios marks strongly autoreactive CD4+ T cells in two major waves of thymic deletion distinguished by induction of PD-1 or NF-κB. J. Exp. Med. 210, 269–285 (2013).
Stritesky, G. L. et al. Murine thymic selection quantified using a unique method to capture deleted T cells. Proc. Natl Acad. Sci. USA 110, 4679–4684 (2013).
Fontenot, J. D., Dooley, J. L., Farr, A. G. & Rudensky, A. Y. Developmental regulation of Foxp3 expression during ontogeny. J. Exp. Med. 202, 901–906 (2005).
Cowan, J. E. et al. The thymic medulla is required for Foxp3+ regulatory but not conventional CD4+ thymocyte development. J. Exp. Med. 210, 675–681 (2013).
Mathis, D. & Benoist, C. Aire. Annu. Rev. Immunol. 27, 287–312 (2009).
Aschenbrenner, K. et al. Selection of Foxp3+ regulatory T cells specific for self antigen expressed and presented by Aire+ medullary thymic epithelial cells. Nat. Immunol. 8, 351–358 (2007).
Yang, S., Fujikado, N., Kolodin, D., Benoist, C. & Mathis, D. Immune tolerance. Regulatory T cells generated early in life play a distinct role in maintaining self-tolerance. Science 348, 589–594 (2015).
Tanaka, S. et al. Graded attenuation of TCR signaling elicits distinct autoimmune diseases by altering thymic T cell selection and regulatory T cell function. J. Immunol. 185, 2295–2305 (2010).
Siggs, O. M. et al. Opposing functions of the T cell receptor kinase ZAP-70 in immunity and tolerance differentially titrate in response to nucleotide substitutions. Immunity 27, 912–926 (2007).
Hsu, L. Y., Tan, Y. X., Xiao, Z., Malissen, M. & Weiss, A. A hypomorphic allele of ZAP-70 reveals a distinct thymic threshold for autoimmune disease versus autoimmune reactivity. J. Exp. Med. 206, 2527–2541 (2009).
Koonpaew, S., Shen, S., Flowers, L. & Zhang, W. LAT-mediated signaling in CD4+CD25+ regulatory T cell development. J. Exp. Med. 203, 119–129 (2006).
Fu, G. et al. Phospholipase Cγ1 is essential for T cell development, activation, and tolerance. J. Exp. Med. 207, 309–318 (2010).
Oh-hora, M. et al. Dual functions for the endoplasmic reticulum calcium sensors STIM1 and STIM2 in T cell activation and tolerance. Nat. Immunol. 9, 432–443 (2008).
Schmidt-Supprian, M. et al. Differential dependence of CD4+CD25+ regulatory and natural killer-like T cells on signals leading to NF-κB activation. Proc. Natl Acad. Sci. USA 101, 4566–4571 (2004).
Gupta, S. et al. Differential requirement of PKC-θ in the development and function of natural regulatory T cells. Mol. Immunol. 46, 213–224 (2008).
Medoff, B. D. et al. Differential requirement for CARMA1 in agonist-selected T-cell development. Eur. J. Immunol. 39, 78–84 (2009).
Barnes, M. J. et al. Commitment to the regulatory T cell lineage requires CARMA1 in the thymus but not in the periphery. PLoS Biol. 7, e51 (2009).
Chen, X., Priatel, J. J., Chow, M. T. & Teh, H. S. Preferential development of CD4 and CD8 T regulatory cells in RasGRP1-deficient mice. J. Immunol. 180, 5973–5982 (2008).
Willoughby, J. E. et al. Raf signaling but not the ERK effector SAP-1 is required for regulatory T cell development. J. Immunol. 179, 6836–6844 (2007).
Schmidt, A. M. et al. Diacylglycerol kinase ζ limits the generation of natural regulatory T cells. Sci. Signal. 6, ra101 (2013).
Joshi, R. P. et al. The ζ isoform of diacylglycerol kinase plays a predominant role in regulatory T cell development and TCR-mediated Ras signaling. Sci. Signal. 6, ra102 (2013).
Long, M., Park, S.-G., Strickland, I., Hayden, M. S. & Ghosh, S. Nuclear factor-κB modulates regulatory T cell development by directly regulating expression of Foxp3 transcription factor. Immunity 31, 921–931 (2009).
Fassett, M. S., Jiang, W., D'Alise, A. M., Mathis, D. & Benoist, C. Nuclear receptor Nr4a1 modulates both regulatory T-cell (Treg) differentiation and clonal deletion. Proc. Natl Acad. Sci. USA 109, 3891–3896 (2012).
Hwang, S. et al. Reduced TCR signaling potential impairs negative selection but does not result in autoimmune disease. J. Exp. Med. 209, 1781–1795 (2012).
Park, Y. et al. SHARPIN controls regulatory T cells by negatively modulating the T cell antigen receptor complex. Nat. Immunol. 17, 286–296 (2016).
Haxhinasto, S., Mathis, D. & Benoist, C. The AKT–mTOR axis regulates de novo differentiation of CD4+Foxp3+ cells. J. Exp. Med. 205, 565–574 (2008).
Patton, D. T. et al. Cutting edge: the phosphoinositide 3-kinase p110δ is critical for the function of CD4+CD25+Foxp3+ regulatory T cells. J. Immunol. 177, 6598–6602 (2006).
Chang, X., Lazorchak, A. S., Liu, D. & Su, B. Sin1 regulates Treg-cell development but is not required for T-cell growth and proliferation. Eur. J. Immunol. 42, 1639–1647 (2012).
Sauer, S. et al. T cell receptor signaling controls Foxp3 expression via PI3K, Akt, and mTOR. Proc. Natl Acad. Sci. USA 105, 7797–7802 (2008).
Ouyang, W. et al. Foxo proteins cooperatively control the differentiation of Foxp3+ regulatory T cells. Nat. Immunol. 11, 618–627 (2010).
Lio, C.-W. J. & Hsieh, C.-S. A. Two-step process for thymic regulatory T cell development. Immunity 28, 100–111 (2008).
Burchill, M. A., Yang, J., Vogtenhuber, C., Blazar, B. R. & Farrar, M. A. IL-2 receptor β-dependent STAT5 activation is required for the development of Foxp3+ regulatory T cells. J. Immunol. 178, 280–290 (2007).
Bautista, J. L. et al. Intraclonal competition limits the fate determination of regulatory T cells in the thymus. Nat. Immunol. 10, 610–617 (2009).
Leung, M. W., Shen, S. & Lafaille, J. J. TCR-dependent differentiation of thymic Foxp3+ cells is limited to small clonal sizes. J. Exp. Med. 206, 2121–2130 (2009).
Le Borgne, M. et al. The impact of negative selection on thymocyte migration in the medulla. Nat. Immunol. 10, 823–830 (2009).
Hinterberger, M. et al. Autonomous role of medullary thymic epithelial cells in central CD4+ T cell tolerance. Nat. Immunol. 11, 512–519 (2010).
Ouyang, W. & Li, M. O. Foxo: in command of T lymphocyte homeostasis and tolerance. Trends Immunol. 32, 26–33 (2011).
Ruan, Q. et al. Development of Foxp3+ regulatory T cells is driven by the c-Rel enhanceosome. Immunity 31, 932–940 (2009).
Vaeth, M. et al. Dependence on nuclear factor of activated T-cells (NFAT) levels discriminates conventional T cells from Foxp3+ regulatory T cells. Proc. Natl Acad. Sci. USA 109, 16258–16263 (2012).
Gomez-Rodriguez, J. et al. Itk-mediated integration of T cell receptor and cytokine signaling regulates the balance between Th17 and regulatory T cells. J. Exp. Med. 211, 529–543 (2014).
Huang, W., Jeong, A. R., Kannan, A. K., Huang, L. & August, A. IL-2-inducible T cell kinase tunes T regulatory cell development and is required for suppressive function. J. Immunol. 193, 2267–2272 (2014).
Chi, H. Regulation and function of mTOR signalling in T cell fate decisions. Nat. Rev. Immunol. 12, 325–338 (2012).
Delgoffe, G. M. et al. The mTOR kinase differentially regulates effector and regulatory T cell lineage commitment. Immunity 30, 832–844 (2009).
Yun, T. J. & Bevan, M. J. The Goldilocks conditions applied to T cell development. Nat. Immunol. 2, 13–14 (2001).
Tai, X., Cowan, M., Feigenbaum, L. & Singer, A. CD28 costimulation of developing thymocytes induces Foxp3 expression and regulatory T cell differentiation independently of interleukin 2. Nat. Immunol. 6, 152–162 (2005).
Hinterberger, M., Wirnsberger, G. & Klein, L. B7/CD28 in central tolerance: costimulation promotes maturation of regulatory T cell precursors and prevents their clonal deletion. Front. Immunol. 2, 30 (2011).
Coquet, J. M. et al. Epithelial and dendritic cells in the thymic medulla promote CD4+Foxp3+ regulatory T cell development via the CD27-CD70 pathway. J. Exp. Med. 210, 715–728 (2013).
Mahmud, S. A. et al. Costimulation via the tumor-necrosis factor receptor superfamily couples TCR signal strength to the thymic differentiation of regulatory T cells. Nat. Immunol. 15, 473–481 (2014).
Benson, M. J., Pino-Lagos, K., Rosemblatt, M. & Noelle, R. J. All-trans retinoic acid mediates enhanced T reg cell growth, differentiation, and gut homing in the face of high levels of co-stimulation. J. Exp. Med. 204, 1765–1774 (2007).
Ordonez-Rueda, D. et al. Increased numbers of thymic and peripheral CD4+CD25+Foxp3+ cells in the absence of CD5 signaling. Eur. J. Immunol. 39, 2233–2247 (2009).
Henderson, J. G., Opejin, A., Jones, A., Gross, C. & Hawiger, D. CD5 instructs extrathymic regulatory T cell development in response to self and tolerizing antigens. Immunity 42, 471–483 (2015).
Zheng, S. G. et al. TGF-β requires CTLA-4 early after T cell activation to induce FoxP3 and generate adaptive CD4+CD25+ regulatory cells. J. Immunol. 176, 3321–3329 (2006).
Francisco, L. M. et al. PD-L1 regulates the development, maintenance, and function of induced regulatory T cells. J. Exp. Med. 206, 3015–3029 (2009).
Ouyang, W., Beckett, O., Ma, Q. & Li, M. O. Transforming growth factor-β signaling curbs thymic negative selection promoting regulatory T cell development. Immunity 32, 642–653 (2010).
Tai, X. et al. Foxp3 transcription factor is proapoptotic and lethal to developing regulatory T cells unless counterbalanced by cytokine survival signals. Immunity 38, 1116–1128 (2013).
Liu, Y. et al. A critical function for TGF-β signaling in the development of natural CD4+CD25+Foxp3+ regulatory T cells. Nat. Immunol. 9, 632–640 (2008).
Chen, W. et al. Conversion of peripheral CD4+CD25− naive T cells to CD4+CD25+ regulatory T cells by TGF-β induction of transcription factor Foxp3. J. Exp. Med. 198, 1875–1886 (2003).
Yao, Z. et al. Nonredundant roles for Stat5a/b in directly regulating Foxp3. Blood 109, 4368–4375 (2007).
Li, M. O. & Flavell, R. A. TGF-β: a master of all T cell trades. Cell 134, 392–404 (2008).
Liao, W., Lin, J. X. & Leonard, W. J. Interleukin-2 at the crossroads of effector responses, tolerance, and immunotherapy. Immunity 38, 13–25 (2013).
Zheng, Y. et al. Role of conserved non-coding DNA elements in the Foxp3 gene in regulatory T-cell fate. Nature 463, 808–812 (2010).
Isomura, I. et al. c-Rel is required for the development of thymic Foxp3+ CD4 regulatory T cells. J. Exp. Med. 206, 3001–3014 (2009).
Harada, Y. et al. Transcription factors Foxo3a and Foxo1 couple the E3 ligase Cbl-b to the induction of Foxp3 expression in induced regulatory T cells. J. Exp. Med. 207, 1381–1391 (2010).
Schuster, M. et al. IκBNS protein mediates regulatory T cell development via induction of the Foxp3 transcription factor. Immunity 37, 998–1008 (2012).
Tone, Y. et al. Smad3 and NFAT cooperate to induce Foxp3 expression through its enhancer. Nat. Immunol. 9, 194–202 (2008).
Sekiya, T. et al. Nr4a receptors are essential for thymic regulatory T cell development and immune homeostasis. Nat. Immunol. 14, 230–237 (2013). This study shows that the TCR-induced immediate early genes encoding the NR4A nuclear receptor family members are crucial for Foxp3 expression, which implies that T Reg cell differentiation is promoted by transcriptional factors activated downstream of TCR signalling.
Gao, P. et al. Dynamic changes in E-protein activity regulate T reg cell development. J. Exp. Med. 211, 2651–2668 (2014).
Liu, C. et al. Id1 expression promotes T regulatory cell differentiation by facilitating TCR costimulation. J. Immunol. 193, 663–672 (2014).
Maruyama, T. et al. Control of the differentiation of regulatory T cells and TH17 cells by the DNA-binding inhibitor Id3. Nat. Immunol. 12, 86–95 (2011).
Feng, Y. et al. A mechanism for expansion of regulatory T-cell repertoire and its role in self-tolerance. Nature 528, 132–136 (2015).
Samstein, R. M. et al. Foxp3 exploits a pre-existent enhancer landscape for regulatory T cell lineage specification. Cell 151, 153–166 (2012).
Ohkura, N. et al. T cell receptor stimulation-induced epigenetic changes and Foxp3 expression are independent and complementary events required for Treg cell development. Immunity 37, 785–799 (2012). References 98 and 99 report that during T Reg cell lineage commitment, FOXP3 expression is preceded by the TCR-dependent establishment of key regulatory elements and changes in DNA methylation at several genomic loci. These changes prepare precursor cells for FOXP3 expression and its essential function in regulating gene expression in T Reg cells.
Kim, H. P. & Leonard, W. J. CREB/ATF-dependent T cell receptor-induced FoxP3 gene expression: a role for DNA methylation. J. Exp. Med. 204, 1543–1551 (2007).
Floess, S. et al. Epigenetic control of the foxp3 locus in regulatory T cells. PLoS Biol. 5, e38 (2007).
Josefowicz, S. Z., Wilson, C. B. & Rudensky, A. Y. Cutting edge: TCR stimulation is sufficient for induction of Foxp3 expression in the absence of DNA methyltransferase 1. J. Immunol. 182, 6648–6652 (2009).
Di Ruscio, A. et al. DNMT1-interacting RNAs block gene-specific DNA methylation. Nature 503, 371–376 (2013).
Stritesky, G. L., Jameson, S. C. & Hogquist, K. A. Selection of self-reactive T cells in the thymus. Annu. Rev. Immunol. 30, 95–114 (2012).
Miyara, M. et al. Functional delineation and differentiation dynamics of human CD4+ T cells expressing the FoxP3 transcription factor. Immunity 30, 899–911 (2009).
Huehn, J. et al. Developmental stage, phenotype, and migration distinguish naive- and effector/memory-like CD4+ regulatory T cells. J. Exp. Med. 199, 303–313 (2004).
Smigiel, K. S. et al. CCR7 provides localized access to IL-2 and defines homeostatically distinct regulatory T cell subsets. J. Exp. Med. 211, 121–136 (2014).
Cheroutre, H., Lambolez, F. & Mucida, D. The light and dark sides of intestinal intraepithelial lymphocytes. Nat. Rev. Immunol. 11, 445–456 (2011).
Hogquist, K. A. & Jameson, S. C. The self-obsession of T cells: how TCR signaling thresholds affect fate 'decisions' and effector function. Nat. Immunol. 15, 815–823 (2014).
Gavin, M. A., Clarke, S. R., Negrou, E., Gallegos, A. & Rudensky, A. Homeostasis and anergy of CD4+CD25+ suppressor T cells in vivo. Nat. Immunol. 3, 33–41 (2002).
Crellin, N. K., Garcia, R. V. & Levings, M. K. Altered activation of AKT is required for the suppressive function of human CD4+CD25+ T regulatory cells. Blood 109, 2014–2022 (2007).
Tai, X. et al. Basis of CTLA-4 function in regulatory and conventional CD4+ T cells. Blood 119, 5155–5163 (2012).
Samy, E. T., Parker, L. A., Sharp, C. P. & Tung, K. S. Continuous control of autoimmune disease by antigen-dependent polyclonal CD4+CD25+ regulatory T cells in the regional lymph node. J. Exp. Med. 202, 771–781 (2005).
Luo, C. T., Liao, W., Dadi, S., Toure, A. & Li, M. O. Graded Foxo1 activity in Treg cells differentiates tumour immunity from spontaneous autoimmunity. Nature 529, 532–536 (2016). This study demonstrates that activated T Reg cell differentiation is associated with the repression of FOXO1-dependent gene transcription, concomitant with AKT-induced FOXO1 phosphorylation. FOXO1 inactivation is essential for the migration of activated T Reg cells to target tissues and the suppression of CD8+ T cell-dependent autoimmunity and tumour immunity.
Rosenblum, M. D. et al. Response to self antigen imprints regulatory memory in tissues. Nature 480, 538–542 (2011).
Levine, A. G., Arvey, A., Jin, W. & Rudensky, A. Y. Continuous requirement for the TCR in regulatory T cell function. Nat. Immunol. 15, 1070–1078 (2014).
Vahl, J. C. et al. Continuous T cell receptor signals maintain a functional regulatory T cell pool. Immunity 41, 722–736 (2014). References 116 and 117 demonstrate that TCR expression in mature T Reg cells is dispensable for maintaining the expression of FOXP3 and the T Reg cell-specific epigenome but is required for the suppressor capacity of T Reg cells.
Feng, Y. et al. Control of the inheritance of regulatory T cell identity by a cis element in the Foxp3 locus. Cell 158, 749–763 (2014).
Li, X., Liang, Y., LeBlanc, M., Benner, C. & Zheng, Y. Function of a Foxp3 cis-element in protecting regulatory T cell identity. Cell 158, 734–748 (2014). References 118 and 119 reveal that the hypomethylated intronic Foxp3 regulatory element CNS2 has an essential function in controlling the T Reg cell identity in antigen-experienced T Reg cells. CNS2 contains cis regulatory motifs that sense cytokine and TCR signals.
Chuck, M. I., Zhu, M., Shen, S. & Zhang, W. The role of the LAT-PLC-γ1 interaction in T regulatory cell function. J. Immunol. 184, 2476–2486 (2010).
Chang, J. H. et al. Ubc13 maintains the suppressive function of regulatory T cells and prevents their conversion into effector-like T cells. Nat. Immunol. 13, 481–490 (2012).
Zeng, H. et al. mTORC1 couples immune signals and metabolic programming to establish Treg-cell function. Nature 499, 485–490 (2013). This study shows that T Reg cells have elevated steady-state mTORC1 activity. mTORC1 deficiency results in compromised T Reg cell function, which is partly due to enhanced mTORC2 signalling and is further associated with defective lipid metabolism.
Onishi, Y., Fehervari, Z., Yamaguchi, T. & Sakaguchi, S. Foxp3+ natural regulatory T cells preferentially form aggregates on dendritic cells in vitro and actively inhibit their maturation. Proc. Natl Acad. Sci. USA 105, 10113–10118 (2008).
Au-Yeung, B. B. et al. A genetically selective inhibitor demonstrates a function for the kinase Zap70 in regulatory T cells independent of its catalytic activity. Nat. Immunol. 11, 1085–1092 (2010).
Ouyang, W. et al. Novel Foxo1-dependent transcriptional programs control Treg cell function. Nature 491, 554–559 (2012). This study reports that T Reg cell differentiation is associated with attenuated AKT-triggered FOXO1 nuclear exclusion. FOXO1 controls a gene expression programme that is distinct from that of FOXP3 and is indispensable for T Reg cell function.
Shrestha, S. et al. Treg cells require the phosphatase PTEN to restrain TH1 and TFH cell responses. Nat. Immunol. 16, 178–187 (2015).
Huynh, A. et al. Control of PI3 kinase in Treg cells maintains homeostasis and lineage stability. Nat. Immunol. 16, 188–196 (2015).
Schneider, M. A., Meingassner, J. G., Lipp, M., Moore, H. D. & Rot, A. CCR7 is required for the in vivo function of CD4+CD25+ regulatory T cells. J. Exp. Med. 204, 735–745 (2007).
Liu, Z. et al. Immune homeostasis enforced by co-localized effector and regulatory T cells. Nature 528, 225–230 (2015). This study reports that T Reg cells expressing phosphorylated STAT5 exist in clusters with conventional IL-2+ T cells in secondary lymphoid tissues, and such colocalization is dependent on T Reg cell expression of TCR. These findings imply a negative feedback mechanism that promotes tolerance control of autoreactive T cells.
deLeeuw, R. J., Kost, S. E., Kakal, J. A. & Nelson, B. H. The prognostic value of FoxP3+ tumor-infiltrating lymphocytes in cancer: a critical review of the literature. Clin. Cancer Res. 18, 3022–3029 (2012).
Hindley, J. P. et al. Analysis of the T-cell receptor repertoires of tumor-infiltrating conventional and regulatory T cells reveals no evidence for conversion in carcinogen-induced tumors. Cancer Res. 71, 736–746 (2011).
Sainz-Perez, A., Lim, A., Lemercier, B. & Leclerc, C. The T-cell receptor repertoire of tumor-infiltrating regulatory T lymphocytes is skewed toward public sequences. Cancer Res. 72, 3557–3569 (2012).
Malchow, S. et al. Aire-dependent thymic development of tumor-associated regulatory T cells. Science 339, 1219–1224 (2013). This study reports that T Reg cells that are reactive to a prostate-associated self antigen are highly enriched in oncogene-induced prostate tumours. Differentiation of these T Reg cells in the thymus is determined by AIRE-dependent expression of prostate tissue antigens by mTECs.
Ali, K. et al. Inactivation of PI3K p110δ breaks regulatory T-cell-mediated immune tolerance to cancer. Nature 510, 407–411 (2014).
Erlebacher, A., Vencato, D., Price, K. A., Zhang, D. & Glimcher, L. H. Constraints in antigen presentation severely restrict T cell recognition of the allogeneic fetus. J. Clin. Invest. 117, 1399–1411 (2007).
Rowe, J. H., Ertelt, J. M., Xin, L. & Way, S. S. Pregnancy imprints regulatory memory that sustains anergy to fetal antigen. Nature 490, 102–106 (2012).
Samstein, R. M., Josefowicz, S. Z., Arvey, A., Treuting, P. M. & Rudensky, A. Y. Extrathymic generation of regulatory T cells in pacental mammals mitigates maternal-fetal conflict. Cell 150, 29–38 (2012). References 136 and 137 show that maternal T Reg cells specific for fetal antigens are induced during pregnancy. pT Reg cell differentiation is dependent on the Foxp3 intronic regulatory element CNS1 that has emerged in placental mammals during evolution. Furthermore, T Reg cells persist post-partum and rapidly expand during subsequent pregnancies. The robust recall (memory) T Reg cell response promotes immune tolerance to the fetus.
Aluvihare, V. R., Kallikourdis, M. & Betz, A. G. Regulatory T cells mediate maternal tolerance to the fetus. Nat. Immunol. 5, 266–271 (2004).
Zenclussen, A. C. et al. Regulatory T cells induce a privileged tolerant microenvironment at the fetal-maternal interface. Eur. J. Immunol. 36, 82–94 (2006).
Mold, J. E. et al. Maternal alloantigens promote the development of tolerogenic fetal regulatory T cells in utero. Science 322, 1562–1565 (2008).
Kinder, J. M. et al. Cross-generational reproductive fitness enforced by microchimeric maternal cells. Cell 162, 505–515 (2015). This study reports that exposure to maternal tissues induces T Reg cell differentiation and stable immune tolerance to non-inherited maternal antigens in female offspring. Such female offspring experience reduced fatal wasting when mated with males that share these antigens.
Lathrop, S. K. et al. Peripheral education of the immune system by colonic commensal microbiota. Nature 478, 250–254 (2011). This study reports that colonic T Reg cells express distinct TCRs, many of which react to antigens derived from commensal bacteria. These TCRs, when expressed in precursor cells, do not facilitate tT Reg cell development but promote microbiota-dependent pT Reg cell differentiation.
Cebula, A. et al. Thymus-derived regulatory T cells contribute to tolerance to commensal microbiota. Nature 497, 258–262 (2013).
Atarashi, K. et al. Treg induction by a rationally selected mixture of Clostridia strains from the human microbiota. Nature 500, 232–236 (2013).
Schlenner, S. M., Weigmann, B., Ruan, Q., Chen, Y. & von Boehmer, H. Smad3 binding to the foxp3 enhancer is dispensable for the development of regulatory T cells with the exception of the gut. J. Exp. Med. 209, 1529–1535 (2012).
Josefowicz, S. Z. et al. Extrathymically generated regulatory T cells control mucosal TH2 inflammation. Nature 482, 395–399 (2012).
Zeiser, R. et al. Differential impact of mammalian target of rapamycin inhibition on CD4+CD25+Foxp3+ regulatory T cells compared with conventional CD4+ T cells. Blood 111, 453–462 (2008).
Klatzmann, D. & Abbas, A. K. The promise of low-dose interleukin-2 therapy for autoimmune and inflammatory diseases. Nat. Rev. Immunol. 15, 283–294 (2015).
Simpson, T. R. et al. Fc-dependent depletion of tumor-infiltrating regulatory T cells co-defines the efficacy of anti-CTLA-4 therapy against melanoma. J. Exp. Med. 210, 1695–1710 (2013).
Bulliard, Y. et al. Activating Fcγ receptors contribute to the antitumor activities of immunoregulatory receptor-targeting antibodies. J. Exp. Med. 210, 1685–1693 (2013).
Selby, M. J. et al. Anti-CTLA-4 antibodies of IgG2a isotype enhance antitumor activity through reduction of intratumoral regulatory T cells. Cancer Immunol. Res. 1, 32–42 (2013).
Acknowledgements
The authors apologize to those whose work they could not cite owing to space constraints. They thank former and current members of Li and Rudensky laboratories for discussions. This work was supported by the US National Institutes of Health (RO1 AI102888-01A1 to M.O.L., R37 A134206 to A.Y.R. and the Memorial Sloan Kettering Cancer Center Core Grant P30 CA008748).
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Glossary
- Clonal deletion
-
The process by which double-positive or single-positive thymocytes that express T cell receptors with high affinity for self antigens are induced to undergo apoptosis.
- Thymus-derived regulatory T cells
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(tTReg cells). T cells with regulatory (suppressive) ability that acquire the transcriptional and epigenetic signature, including forkhead box P3 (FOXP3) expression, in the thymus.
- Peripherally derived TReg cells
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(pTReg cells). T cells with regulatory (suppressive) ability that acquire the transcriptional and epigenetic signature, including forkhead box P3 (FOXP3) expression, in peripheral tissue.
- Autoimmune regulator
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(AIRE). Expressed by medullary thymic epithelial cells, AIRE facilitates the expression of a diverse set of transcripts that are characteristic of different non-lymphoid organs and also affects the cellular composition and architecture of thymic medulla.
- Positive selection
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The process by which CD4 and CD8 double-positive immature thymocytes that express T cell receptors with intermediate affinity for self antigens are induced to differentiate into CD4 or CD8 single-positive thymocytes.
- Mechanistic target of rapamycin
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(mTOR). A conserved serine/threonine protein kinase that regulates cell growth and metabolism, as well as cytokine and growth factor expression, in response to environmental cues. mTOR receives stimulatory signals from RAS and phosphoinositide 3-kinase (PI3K) downstream of growth factors, as well as from nutrients, such as amino acids and glucose.
- In vitro-induced TReg cell
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(iTReg cell). T cell with regulatory (suppressive) ability that acquires the expression of forkhead box P3 (FOXP3) under specific T cell culture conditions.
- Intestinal intraepithelial lymphocytes
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(IELs). A T cell population that is found in the epithelial layer of the gastrointestinal tract lining. Unlike conventional lineage T cells, IELs are selected by agonist antigens and exert immediate effector functions in response to antigens and stress signals.
- Resting TReg cells
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TReg cells that are phenotypically similar to conventional naive CD4+ T cells with high expression of CD62L in mice or CD45RA in humans.
- Activated TReg cells
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TReg cells that are phenotypically similar to conventional effector or effector memory CD4+ T cells with low expression of CD62L in mice or CD45RA in humans.
- Recent thymic emigrants
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T cells that have completed thymic development and have recently entered the lymphoid periphery. These young T cells undergo a maturation process that includes changes in function and cell surface phenotype.
- TCR retrogenic mice
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Mice that express a defined TCRα and TCRβ proteins from retroviral vectors following retrovirus-mediated haematopoietic stem cell gene transfer.
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Li, M., Rudensky, A. T cell receptor signalling in the control of regulatory T cell differentiation and function. Nat Rev Immunol 16, 220–233 (2016). https://doi.org/10.1038/nri.2016.26
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DOI: https://doi.org/10.1038/nri.2016.26
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