1
|
Abstract
A major goal of immunosuppressive therapies is to harness immune tolerance mechanisms so as to minimize unwanted side effects associated with protracted immunosuppressive therapy. Antibody blockade of lymphocyte coreceptor and costimulatory pathways in mice has demonstrated the principle that both naive and primed immune systems can be reprogrammed toward immunological tolerance. Such tolerance can involve the amplification of activity of regulatory T cells, and is maintained through continuous recruitment of such cells through processes of infectious tolerance. We propose that regulatory T cells create around them microenvironments that are anti-inflammatory and endowed with enhanced protection against destructive damage. This acquired immune privilege involves the decommissioning of cells of the innate as well as adaptive immune systems. Evidence is presented that nutrient sensing by immune cells acting through the mammalian target of rapamycin (mTOR) pathway provides one route by which the immune system can be directed toward noninflammatory and regulatory behavior at the expense of destructive functions. Therapeutic control of immune cells so as to harness metabolic routes favoring dominant regulatory mechanisms has offered a new direction for immunosuppressive therapy, whereby short-term treatment may be sufficient for long-term benefit or even cure.
Collapse
|
2
|
Caridade M, Graca L, Ribeiro RM. Mechanisms Underlying CD4+ Treg Immune Regulation in the Adult: From Experiments to Models. Front Immunol 2013; 4:378. [PMID: 24302924 PMCID: PMC3831161 DOI: 10.3389/fimmu.2013.00378] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 11/03/2013] [Indexed: 12/29/2022] Open
Abstract
To maintain immunological balance the organism has to be tolerant to self while remaining competent to mount an effective immune response against third-party antigens. An important mechanism of this immune regulation involves the action of regulatory T-cell (Tregs). In this mini-review, we discuss some of the known and proposed mechanisms by which Tregs exert their influence in the context of immune regulation, and the contribution of mathematical modeling for these mechanistic studies. These models explore the mechanisms of action of regulatory T cells, and include hypotheses of multiple signals, delivered through simultaneous antigen-presenting cell (APC) conjugation; interaction of feedback loops between APC, Tregs, and effector cells; or production of specific cytokines that act on effector cells. As the field matures, and competing models are winnowed out, it is likely that we will be able to quantify how tolerance-inducing strategies, such as CD4-blockade, affect T-cell dynamics and what mechanisms explain the observed behavior of T-cell based tolerance.
Collapse
Affiliation(s)
- Marta Caridade
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa , Lisbon , Portugal ; Instituto Gulbenkian de Ciência , Oeiras , Portugal
| | | | | |
Collapse
|
3
|
Cobbold SP, Adams E, Nolan KF, Regateiro FS, Waldmann H. Connecting the mechanisms of T-cell regulation: dendritic cells as the missing link. Immunol Rev 2010; 236:203-18. [PMID: 20636819 DOI: 10.1111/j.1600-065x.2010.00913.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A variety of different molecular mechanisms have been proposed to explain the suppressive action of regulatory T cells, including the production of anti-inflammatory cytokines, negative costimulatory ligands, indoleamine 2,3-dioxygenase-mediated tryptophan catabolism, CD73-mediated adenosine generation, and downregulation of antigen-presenting cells. Until now it has been unclear how important each of these different mechanisms might be and how they are coordinated. In this review, we examine the hypothesis that it is the interaction between regulatory T cells and dendritic cells that creates a local microenvironment depleted of essential amino acids and rich in adenosine that leads to the amplification of a range of different tolerogenic signals. These signals are all eventually integrated by mammalian target of rapamycin inhibition, which enables the induction of new forkhead box protein 3-expressing Tregs. If correct, this provides a molecular explanation for the in vivo phenomena of linked suppression and infectious tolerance.
Collapse
Affiliation(s)
- Stephen P Cobbold
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
| | | | | | | | | |
Collapse
|
4
|
Noël G, Brinster C, Semana G, Bruniquel D. Modulation of the TCR stimulation strength can render human activated CD4+ T cells suppressive. Int Immunol 2009; 21:1025-36. [PMID: 19625380 DOI: 10.1093/intimm/dxp068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In this study, we explored the potential of human naive CD4(+) T cells to acquire regulatory properties upon stimulation. We demonstrated that, in vitro, pre-activated naive CD4(+)CD25(-)CD45RA(+) T cells could become anergic and suppressive CD4(+)CD25(+) T cells upon lower intensity TCR stimulation. These CD4(+)CD25(+) T cells generated in vitro potently suppress the proliferation of allogenic CD4(+)CD25(-) T cells independently of cytokines and in a contact-dependent manner. Our data indicate that expression of Foxp3 is not necessary to induce the suppressive T cell activity. We demonstrate that these CD4(+)CD25(+) T cells are unresponsive upon re-stimulation and that their suppressive activity is transient. However, we showed that the anergy and the suppressive function could be reversed by increasing the stimulus and their level of activation. We concluded from our data that these anergy and suppressive activities are related to a fine tuning of TCR activation threshold.
Collapse
Affiliation(s)
- Grégory Noël
- UPRES 3889, Faculté de Médecine, Laboratoire d'Immuno-Hématologie, 2 avenue du Professeur Léon Bernard, 35043 Rennes cedex, France
| | | | | | | |
Collapse
|
5
|
Regulation and Privilege in Transplantation Tolerance. J Clin Immunol 2008; 28:716-25. [DOI: 10.1007/s10875-008-9249-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Accepted: 08/01/2008] [Indexed: 02/03/2023]
|
6
|
|
7
|
Waldmann H, Adams E, Fairchild P, Cobbold S. Infectious tolerance and the long-term acceptance of transplanted tissue. Immunol Rev 2006; 212:301-13. [PMID: 16903922 DOI: 10.1111/j.0105-2896.2006.00406.x] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Short courses of antibody treatment aimed at blocking the coreceptors CD4 and CD8 and/or costimulatory molecules such as CD40L are able to bring about long-term acceptance and tolerance of allogeneic transplants. This tolerant state is operational, in that potential effector cells remain but are tightly regulated through the induction of antigen-specific CD4+ regulatory T cells (Tregs). CD4+ CD25+ FoxP3+ Tregs appear to play a prominent role, although other categories of Tregs have been documented. Transforming growth factor beta (TGFbeta) has been found to play a major role in the induction of the tolerant state with therapeutic antibodies as well as promoting the induction of FoxP3+ T cells from naïve populations. The observation that Tregs can be found in tolerated grafts has led to the idea that they may interact with the grafted tissue to establish a state of acquired privilege symmetrical with a similar privileged microenvironment around antigen-presenting cells in lymphoid tissues. Dampening of aggressive immune responses by Tregs allows antigen to persist and be presented in an innocuous way to promote tolerance in new cohorts of T cells throughout the life of the tolerated graft. Regulation may operate at many stages of an immune response, even as a censor at the terminal differentiation stages of effector function.
Collapse
|
8
|
Abstract
Our ability to harness tolerance mechanisms will have a major impact in organ transplantation. It should enable drug minimization, and eventually, the elimination of all immunosuppressive drugs. An improved understanding of the biology of regulatory T cells will make it possible to replace current induction regimens with those favouring the selective vaccination of T cells that prevent graft rejection. Once regulation is established, the continued supply of graft antigens should empower T cell regulation to become the dominant natural mechanism to prevent graft rejection.
Collapse
Affiliation(s)
- Herman Waldmann
- Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE, UK.
| | | | | | | | | | | | | |
Collapse
|
9
|
Waldmann H, Graca L, Adams E, Fairchild P, Cobbold S. Regulatory T cells in transplantation tolerance. Curr Top Microbiol Immunol 2005; 293:249-64. [PMID: 15981483 DOI: 10.1007/3-540-27702-1_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Our ability to harness tolerance mechanisms will have a major impact in organ transplantation if it becomes possible to minimize drug maintenance, or even wean off immunosuppressive drugs. An improved understanding of the biology of regulatory T cells will make it possible to replace current induction regimens with those favouring the vaccination and selection of T cells that prevent graft rejection. Once tolerance is established, the continuous supply of graft antigens should sustain T cell mediated regulation as the dominant mechanism preventing graft rejection.
Collapse
Affiliation(s)
- H Waldmann
- Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE, UK.
| | | | | | | | | |
Collapse
|
10
|
Abstract
Regulatory T cells are now recognized as important mediators of self-tolerance and may mediate responses to immune therapy. The mechanisms of action of these cells are diverse, and some studies suggest that there may be defects in regulatory cells in patients with type 1 diabetes. These cells may be expanded by immune therapy, suggesting the possible development of adoptive immune therapy to transfer regulation with the cells.
Collapse
Affiliation(s)
- Brygida C Bisikirska
- Division of Endocrinology, Naomi Berrie Diabetes Center, Department of Medicine, College of Physicians and Surgeons, Columbia University, Room 10-105, 630 W. 168th Street, New York, NY 10032, USA
| | | |
Collapse
|
11
|
Chen TC, Cobbold SP, Fairchild PJ, Waldmann H. Generation of Anergic and Regulatory T Cells following Prolonged Exposure to a Harmless Antigen. THE JOURNAL OF IMMUNOLOGY 2004; 172:5900-7. [PMID: 15128770 DOI: 10.4049/jimmunol.172.10.5900] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Regulatory CD4(+) T cells are known to develop during the induction of donor-specific peripheral tolerance to transplanted tissues; it is proposed that such tolerance is a consequence of persistent, danger-free stimulation by Ag. To test this hypothesis, male RAG-1(-/-) mice were recolonized with small numbers of monospecific CD4(+) T cells specific for the male H-2E(k)-restricted Ag Dby. After 6 wk in the male environment, the monospecific CD4(+) T cells, having recolonized the host, had become anergic to stimulation in vitro and had acquired a regulatory capacity. CD4(+) T cells in these mice expressed higher levels of CTLA-4 and glucocorticoid-induced TNF-related receptor than naive CD4(+) T cells, but only 3% of the recolonizing cells were CD25(+) and did not express significant foxP3 mRNA. In vivo, these tolerant T cells could censor accumulation of, and IFN-gamma production by, naive T cells, with only a slight inhibition of proliferation. This suppressive effect was not reversed by the addition of fresh bone marrow-derived male dendritic cells. These results suggest that persistent exposure to Ag in conditions that fail to evoke proinflammatory stimuli leads to the development of T cells that are both anergic and regulatory.
Collapse
Affiliation(s)
- Tse-Ching Chen
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | | | | | | |
Collapse
|
12
|
Cobbold SP, Nolan KF, Graca L, Castejon R, Le Moine A, Frewin M, Humm S, Adams E, Thompson S, Zelenika D, Paterson A, Yates S, Fairchild PJ, Waldmann H. Regulatory T cells and dendritic cells in transplantation tolerance: molecular markers and mechanisms. Immunol Rev 2003; 196:109-24. [PMID: 14617201 DOI: 10.1046/j.1600-065x.2003.00078.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Transplantation tolerance can be induced in adult rodents using monoclonal antibodies against coreceptor or costimulation molecules on the surface of T cells. There are currently two well-characterized populations of T cells, demonstrating regulatory capacity: the "natural" CD4+CD25+ T cells and the interleukin (IL)-10-producing Tr1 cells. Although both types of regulatory T cells can induce transplantation tolerance under appropriate conditions, it is not clear whether either one plays any role in drug-induced dominant tolerance, primarily due to a lack of clear-cut molecular or functional markers. Similarly, although dendritic cells (DCs) can be pharmacologically manipulated to promote tolerance, the phenotype of such populations remains poorly defined. We have used serial analysis of gene expression (SAGE) with 29 different T-cell and antigen-presenting cell libraries to identify gene-expression signatures associated with immune regulation. We found that independently derived, regulatory Tr1-like clones were highly concordant in their patterns of gene expression but were quite distinct from CD4+CD25+ regulatory T cells from the spleen. DCs that were treated with the tolerance-enhancing agents IL-10 or vitamin D3 expressed a gene signature reflecting a functional specification in common with the most immature DCs derived from embryonic stem cells.
Collapse
Affiliation(s)
- Stephen P Cobbold
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Abstract
The immune system is organized so as to react to pathogens without risking damage to self. Harnessing those processes that prevent self-reactivity will have enormous potential in clinical medicine. This review outlines the efforts of this laboratory over the last 25 years to exploit tolerance so as to reprogram the immune system for therapeutic purposes.
Collapse
Affiliation(s)
- Herman Waldmann
- Sir William Dunn School of Pathology, South Parks Road, Oxford, UK.
| |
Collapse
|
14
|
Baxter AG, Hodgkin PD. Activation rules: the two-signal theories of immune activation. Nat Rev Immunol 2002; 2:439-46. [PMID: 12093010 DOI: 10.1038/nri823] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Two-signal theories of lymphocyte activation have evolved considerably over the past 35 years. In this article, we examine the contemporary experimental observations and theoretical concerns that have helped to forge the most influential variants of the theory. We also propose that more-rigorous quantitative methods are required to sustain theoretical development in the future.
Collapse
Affiliation(s)
- Alan G Baxter
- Centenary Institute of Cancer Medicine and Cell Biology, Newtown, New South Wales, Australia.
| | | |
Collapse
|
15
|
Borghans JAM, De Boer RJ. Memorizing innate instructions requires a sufficiently specific adaptive immune system. Int Immunol 2002; 14:525-32. [PMID: 11978782 DOI: 10.1093/intimm/14.5.525] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
During its primary encounter with a pathogen, the immune system has to decide which type of immune response is most appropriate. Based on signals from the innate immune system and the immunological context in which the pathogen is presented, responding lymphocytes will adopt a particular phenotype, e.g. secrete a particular profile of cytokines. Once stimulated, lymphocytes store the appropriate type of response by differentiating from a naive to a memory phenotype. This allows the appropriate type of immune reaction to be regenerated upon re-stimulation of those memory clones. We developed a computer simulation model in which cross-reacting effector/memory clones contribute to the immunological context of pathogens. If a pathogen is recognized by both naive clones and pre-existing effector/memory clones, the naive lymphocytes adopt the effector mechanism of the memory clone. The adaptive immune system thereby stores immunological decisions and somatically learns to induce the right type of immune response to pathogens sharing epitopes. The influence of effector/memory lymphocytes may be detrimental when they cross-react to new pathogens that require a different kind of immune response. Here, we show that the immune system needs to be sufficiently specific to avoid such mistakes and to profit from the information that is stored in effector/memory lymphocytes. Repertoire diversity is required to reconcile this specificity with reactivity against many pathogens.
Collapse
Affiliation(s)
- José A M Borghans
- Lymphocyte Population Biology, Institut Pasteur, 25-28 Rue du Dr Roux, 75015 Paris, France.
| | | |
Collapse
|
16
|
Frasca L, Scottà C, Lombardi G, Piccolella E. Human anergic CD4+ T cells can act as suppressor cells by affecting autologous dendritic cell conditioning and survival. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:1060-8. [PMID: 11801639 DOI: 10.4049/jimmunol.168.3.1060] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
T cell suppression exerted by regulatory T cells represents a well-established phenomenon, but the mechanisms involved are still a matter of debate. Recent data suggest that anergic T cells can suppress responder T cell activation by inhibiting Ag presentation by dendritic cells (DC). In this study, we focused our attention on the mechanisms that regulate the susceptibility of DC to suppressive signals and analyzed the fate of DC and responder T cells. To address this issue, we have cocultured human alloreactive or Ag-specific CD4+ T cell clones, rendered anergic by incubation with immobilized anti-CD3 Ab, with autologous DC and responder T cells. We show that anergic T cells affect either Ag-presenting functions or survival of DC, depending whether immature or mature DC are used as APC. Indeed, MHC and costimulatory molecule expression on immature DC activated by responder T cells is inhibited, while apoptotic programs are induced in mature DC and in turn in responder T cells. Ligation of CD95 by CD95L expressed on anergic T cells in the absence of CD40-CD40L (CD154) interaction are critical parameters in eliciting apoptosis in both DC and responder T cells. In conclusion, these findings indicate that the defective activation of CD40 on DC by CD95L+ CD154-defective anergic T cells could be the primary event in determining T cell suppression and support the role of CD40 signaling in regulating both conditioning and survival of DC.
Collapse
Affiliation(s)
- Loredana Frasca
- Department of Cellular and Developmental Biology, La Sapienza University, Via dei Sardi, 70-00185 Rome, Italy
| | | | | | | |
Collapse
|
17
|
Lechler R, Chai JG, Marelli-Berg F, Lombardi G. T-cell anergy and peripheral T-cell tolerance. Philos Trans R Soc Lond B Biol Sci 2001; 356:625-37. [PMID: 11375066 PMCID: PMC1088450 DOI: 10.1098/rstb.2001.0844] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The discovery that T-cell recognition of antigen can have distinct outcomes has advanced understanding of peripheral T-cell tolerance, and opened up new possibilities in immunotherapy. Anergy is one such outcome, and results from partial T-cell activation. This can arise either due to subtle alteration of the antigen, leading to a lower-affinity cognate interaction, or due to a lack of adequate co-stimulation. The signalling defects in anergic T cells are partially defined, and suggest that T-cell receptor (TCR) proximal, as well as downstream defects negatively regulate the anergic T cell's ability to be activated. Most importantly, the use of TCR-transgenic mice has provided compelling evidence that anergy is an in vivo phenomenon, and not merely an in vitro artefact. These findings raise the question as to whether anergic T cells have any biological function. Studies in rodents and in man suggest that anergic T cells acquire regulatory properties; the regulatory effects of anergic T cells require cell to cell contact, and appear to be mediated by inhibition of antigen-presenting cell immunogenicity. Close similarities exist between anergic T cells, and the recently defined CD4+ CD25+ population of spontaneously arising regulatory cells that serve to inhibit autoimmunity in mice. Taken together, these findings suggest that a spectrum of regulatory T cells exists. At one end of the spectrum are cells, such as anergic and CD4+ CD25+ T cells, which regulate via cell-to-cell contact. At the other end of the spectrum are cells which secrete antiinflammatory cytokines such as interleukin 10 and transforming growth factor-beta. The challenge is to devise strategies that reliably induce T-cell anergy in vivo, as a means of inhibiting immunity to allo- and autoantigens.
Collapse
Affiliation(s)
- R Lechler
- Department of Immunology, Imperial College School of Medicine, Hammersmith Campus, Du Cane Road, London W12 0NN,UK.
| | | | | | | |
Collapse
|
18
|
Lechler R, Chai JG, Marelli-Berg F, Lombardi G. The contributions of T-cell anergy to peripheral T-cell tolerance. Immunology 2001; 103:262-9. [PMID: 11454055 PMCID: PMC1783252 DOI: 10.1046/j.1365-2567.2001.01250.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- R Lechler
- Department of Immunology, Imperial College School of Medicine, London, UK.
| | | | | | | |
Collapse
|
19
|
Waldmann H, Cobbold S. Regulating the immune response to transplants. a role for CD4+ regulatory cells? Immunity 2001; 14:399-406. [PMID: 11336685 DOI: 10.1016/s1074-7613(01)00120-0] [Citation(s) in RCA: 186] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- H Waldmann
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom.
| | | |
Collapse
|
20
|
Abstract
T cell anergy is one of the mechanisms leading to the establishment and maintenance of peripheral tolerance. Recent data from our and other laboratories indicate that anergic T cells are not functionally inert but in fact are capable of regulating the immune response in an active manner. In this review, we describe our viewpoint on how anergic self-reactive T cells could contribute to regulation of the immune response.
Collapse
Affiliation(s)
- L S Taams
- Institute of Infectious Diseases and Immunology, Department of Immunology, Utrecht University, The Netherlands
| | | |
Collapse
|
21
|
|
22
|
Luo Z, Gotoh M, Grochowiecki T, Tanaka T, Kimura F, Kawashima H, Yagita H, Okumura K, Miyasaka M. Anergic T cells generated in vitro suppress rejection response to islet allografts. Transplantation 2000; 69:2144-8. [PMID: 10852614 DOI: 10.1097/00007890-200005270-00032] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Induction of antigen-specific unresponsiveness to grafts is the ultimate goal for organ transplantation. It has been shown that anergic T cells generated in vivo can be transferred as suppressor cells. Anergic cells generated in vitro have never been successfully used to prevent allograft rejection in vivo. We examined whether anergic cells generated in vitro by blocking CD28/B7 costimulatory pathway can suppress allograft rejection in vivo. METHODS Anergic T cells were generated in vitro by the addition of anti-B7-1 and anti-B7-2 monoclonal antibodies (mAbs) to primary mixed lymphocyte reaction (MLR) consisting of C57BL/6 (B6) splenocytes as responder and irradiated BALB/c splenocytes as stimulator. We tested the ability of these cells to respond to various stimuli and to suppress alloreactive T-cell responses in vitro. For in vivo studies, 4x10(7) anergic cells were injected intravenously immediately after transplantation of BALB/c islets under the renal subcapsular space of streptozotocin-induced diabetic and 2.5-Gy X-irradiated B6 mice. RESULTS Anergic cells treated with both mAbs in the primary MLR did not proliferate in secondary MLR against BALB/c and third-party C3H/He stimulators. The cells also failed to respond to immobilized anti-CD3 mAb, although they proliferated in response to concanavalin A or phorbol myristate acetate + ionomycin. The anergic state was reversed by the addition of exogenous IL-2. Furthermore, these cells suppressed the proliferation of naive B6 T cells against either the same (BALB/c) or third-party (C3H/He) stimulator cells. In in vivo studies, irradiated B6 mice rejected BALB/c islet allografts acutely with a mean survival time of 27.0+/-8.3 days, whereas two of six animals injected with the anergic cells accepted the allografts indefinitely (>100 days) with a mean survival time of 52.0+/-38.2 days. CONCLUSIONS Anergic cells generated in vitro by blocking CD28/B7 costimulatory pathway suppress islet allograft rejection after adoptive transfer. This procedure might be clinically useful for promoting allograft survival.
Collapse
Affiliation(s)
- Z Luo
- Department of Bioregulation, Osaka University Medical School, Suita, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Alferink J, Aigner S, Reibke R, Hämmerling GJ, Arnold B. Peripheral T-cell tolerance: the contribution of permissive T-cell migration into parenchymal tissues of the neonate. Immunol Rev 1999; 169:255-61. [PMID: 10450522 DOI: 10.1111/j.1600-065x.1999.tb01320.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
T lymphocytes with self-destructive capacity are often found in healthy individuals, indicating efficient control mechanisms that prevent chronic autoimmune diseases. Since naive T lymphocytes do not circulate through extralymphoid tissues the concept has emerged that peripheral T cells ignore tissue-specific antigens unless they are presented by professional antigen-presenting cells in the lymphoid compartments. However, this view pays attention only to experiments performed in adult animals. This report reviews the evidence that tissues of neonatal mice, in contrast to adults, exhibit high accessibility for naive T cells, thereby allowing the direct contact with tissue-specific self-antigens on parenchymal cells during neonatal life and tolerance induction to such self-antigens. In mouse bone marrow chimeras generated at different ages, recent thymic emigrants were tolerized to a major histocompatibility class I antigen expressed on keratinocytes only during a neonatal period and not during adulthood. Blockade of T-cell migration neonatally prevented tolerance induction. The neonatally induced tolerance is maintained during adulthood, apparently by a dominant regulatory mechanism. Thus, parenchymal cells and T-cell migration in the neonate contribute to the control of autoreactive T cells.
Collapse
Affiliation(s)
- J Alferink
- Institute of Medical Microbiology/Hygiene, Technical University of Munich, Germany
| | | | | | | | | |
Collapse
|
24
|
Waldmann H, Bemelman F, Cobbold S. Tolerance induction with CD4 monoclonal antibodies. NOVARTIS FOUNDATION SYMPOSIUM 1998; 215:146-52; discussion 152-8, 186-90. [PMID: 9760577 DOI: 10.1002/9780470515525.ch11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
One of the major goals of therapeutic immunosuppression is to be able to use short-term therapy to achieve long-term tolerance. Short courses of CD4 antibodies are able to create peripheral tolerance in a mature immune system. The resulting tolerant state shows evidence of being dominant in that one can observe the features of linked suppression, transferable suppression and infectious tolerance in a variety of model systems. Only in the situation of administration of high doses of marrow could one find evidence of central and peripheral tolerance which had all the features of being deletional rather than regulatory. These findings suggest that attaining dominant tolerance and linked suppression may be the least invasive of all tolerance-inducing strategies for clinical application.
Collapse
Affiliation(s)
- H Waldmann
- Sir William Dunn School of Pathology, Oxford, UK
| | | | | |
Collapse
|
25
|
Taams LS, van Rensen AJ, Poelen MC, van Els CA, Besseling AC, Wagenaar JP, van Eden W, Wauben MH. Anergic T cells actively suppress T cell responses via the antigen-presenting cell. Eur J Immunol 1998; 28:2902-12. [PMID: 9754577 DOI: 10.1002/(sici)1521-4141(199809)28:09<2902::aid-immu2902>3.0.co;2-b] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We here show that anergic T cells are active mediators of T cell suppression. In co-culture experiments, we found that anergic T cells, derived from established rat T cell clones and rendered anergic via T cell presentation of the specific antigen (Ag), were active inhibitors of T cell responses. Anergic T cells inhibited not only the responses of T cells with the same Ag specificity as the anergic T cells, but were also capable of efficiently inhibiting polyclonal T cell responses directed to other epitopes. This suppression required close cell-cell contact between antigen-presenting cells (APC), anergic T cells and responder T cells, and only occurred when the epitope recognized by the anergic T cell was present. The suppression was not caused by passive competition for ligands on the APC surface, IL-2 consumption, or cytolysis, and was not mediated by soluble factors derived from anergic T cells that were stimulated with their specific Ag. When responder T cells were added 24 h after co-culturing anergic cells in the presence of Ag and APC, T cell responses were still suppressed, indicating that the suppressive effect was persistently present. However, anergic T cells were not able to suppress responder T cells that had already received a full activation signal. We propose that suppression by anergic T cells is mediated via the APC, either through modulation of the T cell-activating capacity of the APC (APC/T cell interaction), or by inhibition of T cells recognizing their ligand in close proximity on the same APC (T/T cell interaction).
Collapse
Affiliation(s)
- L S Taams
- Institute of Infectious Diseases and Immunology, Department of Immunology, Faculty of Veterinary Medicine, Utrecht University, The Netherlands
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Waldmann H, Cobbold S. How do monoclonal antibodies induce tolerance? A role for infectious tolerance? Annu Rev Immunol 1998; 16:619-44. [PMID: 9597144 DOI: 10.1146/annurev.immunol.16.1.619] [Citation(s) in RCA: 176] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
One of the major goals in therapeutic immunosuppression has been to achieve long-term benefit from short-term therapy. The discovery in the mild-1980s that CD4 antibodies can induce immunological tolerance without depleting CD4+ T cells has reawakened interest in the use of nondepleting monoclonal antibodies for reprogramming the immune system in autoimmunity and in transplantation. Since that time, antibodies to CD11a, CD4OL, CD25, CD3, and CTLA4-Ig have all been shown capable of facilitating tolerance. In order to apply to principle of reprogramming in the clinic, we have sought to understand the mechanisms that are involved in its induction and its maintenance. In a number of allogeneic transplant models (heart, skin, bone marrow) anti-CD4 (+/- CD8) antibodies can be shown to block the rejection process while selectively promoting the development of CD4+ regulatory T cells responsible for a dominant tolerance that is reflected in findings of linked suppression and infectious tolerance. In these models, T cells that have never been exposed to CD4 antibodies become tolerant to grafted antigens by experiencing antigen in the microenvironment of regulatory T cells. Dominant tolerance is not the only mechanism that can be facilitated by CD4 Mab therapy. If allogeneic marrow is given at high cell doses under the umbrella of CD4 and CD8 antibodies, then tolerance can be achieved through clonal deletion. The mechanism by which regulatory CD4+ T cell suppress is not yet defined but could be active or passive. We have proposed the "civil service model" to explain how tolerant T cells might interfere with the responses of competent T cells in such a way as to render them tolerant.
Collapse
Affiliation(s)
- H Waldmann
- Sir William Dunn School of Pathology, Oxford, United Kingdom
| | | |
Collapse
|
27
|
Abstract
The crucial cell for immune system control is the T-cell. Current theories for T-cell control lack a credible mechanism for active down-regulation, because any mechanism that actively switches off T-cells must be secure from duplication by invading organisms. This hypothesis presents a system for T-cell control which is secure because it requires recognition of the highly polymorphic molecules of the MHC by the T-cell receptor as the down-regulatory mechanism, thus using the MHC as a form of individual security code.
Collapse
Affiliation(s)
- D W Gray
- Nuffield Department of Surgery, University of Oxford, UK
| |
Collapse
|
28
|
Saloga J, Enk AH, Becker D, Bellinghausen I, Kühn S, Knop J. Active suppression induced by cutaneous exposure to bacterial superantigen is prevented by interleukin-12 treatment in vivo. Immunology 1998; 93:485-92. [PMID: 9659219 PMCID: PMC1364125 DOI: 10.1046/j.1365-2567.1998.00467.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Exposure to the bacterial superantigen staphylococcal enterotoxin B (SEB) leads to inhibition of several immune responses and the induction of regulatory cells. The aim of this study was to characterize these regulatory cells further and to investigate the effect of interleukin-12 (IL-12) on superantigen-induced suppression. For this purpose BALB/c mice were injected subcutaneously with low doses of SEB that did not deplete the SEB-reactive V beta T cells. Intravenous transfer of unseparated local-draining lymph node cells from these SEB-treated animals suppressed the proliferative response of mononuclear spleen cells of naive syngeneic recipients for at least 3 weeks. The regulatory cells did not produce the type 2 cytokines, interleukin-4 (IL-4) or interleukin-10 (IL-10), or increased amounts of transforming growth factor-beta (TGF-beta). Depletion of CD8+ or SEB-reactive V beta 7+ and V beta 8+ T cells, prior to transfer, abrogated the suppressive effect. Intraperitoneal injections of IL-12 into donors, prior to SEB treatment, prevented the induction of functional regulatory cells, and treatment of recipients with IL-12, prior to receipt of cells from SEB-treated donors, prevented the suppressive effect of regulatory cells that were already induced. The data indicate that exposure to minute amounts of superantigens directly induces superantigen-reactive and CD8+ regulatory T cells and that superantigen-induced suppression can be prevented and reversed by IL-12 treatment in vivo.
Collapse
Affiliation(s)
- J Saloga
- Department of Dermatology, University of Mainz, Germany
| | | | | | | | | | | |
Collapse
|
29
|
Abstract
Although the phenomenon of T cell-mediated suppression is well established, particularly in experimental models of transplantation, the mechanisms involved in this form of immunoregulation remain controversial. We have recently demonstrated, using an in vitro system, that anergic T cells can act as suppressor cells by competing for the membrane of the antigen-presenting cell (APC) and for locally produced interleukin-2. In the experiments described here we have explored the ability of anergic T cells to effect linked suppression in antigen-specific and allospecific responses. We observed that anergic antigen-specific CD4+ T cells can inhibit T cells restricted by a different major histocompatibility complex (MHC) class II molecule provided that both restriction elements are expressed by the same APC. In addition, anergic allospecific clones could also effect linked suppression since they could regulate not only T cells specific for the same alloantigen but also responder T cells with direct allospecificity for a second allogeneic MHC molecule or with indirect, self MHC-restricted allospecificity for a processed MHC class I alloantigen. Furthermore, the regulatory effect of the anergic T cells was dependent on cell contact, was not dependent upon irradiation, and was maintained during in vitro culture. These data demonstrate that linked suppression can be effected by anergic T cells in vitro. In the clinical context this raises the possibility that induction of tolerance to a single alloantigen could serve to regulate the immune response to an allograft carrying several MHC and minor antigen differences.
Collapse
Affiliation(s)
- L Frasca
- Department of Immunology, Imperial College of Science, Technology and Medicine, Hammersmith Hospital, London, GB
| | | | | | | |
Collapse
|
30
|
Goss JA, Flye MW, Lacy PE. Successful transfer of immune unresponsiveness to concordant rat islet xenografts. Transplantation 1996; 61:9-13. [PMID: 8560581 DOI: 10.1097/00007890-199601150-00003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Indefinite survival of concordant xenogeneic Wistar Furth (WF) rat islet survival was obtained by intrahepatic transplants of cultured WF islets and a single injection of antilymphocyte sera in C57BL/6 mice. Adoptive transfer of splenocytes from mice with established WF islet xenografts produced a marked prolongation of survival of WF islets transplanted under the kidney capsule of diabetic irradiated (600 rads), naive C57BL/6 recipients (mean survival time = 48.9 +/- 17.1 days), and three of the recipients were still normoglycemic at 100 days after transplantation. Adoptive transfer of an equal mixture (3 x 10(7) cells each) of these splenocytes with normal splenocytes also prolonged survival of the kidney capsule islet xenografts (mean survival time = 26.5 +/- 7.8 days vs. 15.2 +/- 5.3 days for controls). In vitro studies on lymphocyte proliferation demonstrated a low rate of proliferation of splenocytes from established islet xenografts in the presence of irradiated WF splenocytes (stimulation index = 1.6 vs. 16.2 for naive C57Bl/6 mice), and mixing the cells with control splenocytes also decreased the proliferation of splenocytes as compared with controls (stimulation index = 5.4 vs. 16.2 in controls). The inhibitory effect was not species specific, since splenocytes from mice with established islet xenografts also produced a 42% inhibition of proliferation in the presence of irradiated Lewis splenocytes. These findings demonstrate that concordant, islet xenograft, immune unresponsiveness can be adoptively transferred by splencotyes from mice with established islet xenografts.
Collapse
Affiliation(s)
- J A Goss
- Department of Surgery, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | | | | |
Collapse
|
31
|
van Lent PL, Holthuysen AE, van den Bersselaar L, van Rooijen N, van de Putte LB, van den Berg WB. Role of macrophage-like synovial lining cells in localization and expression of experimental arthritis. Scand J Rheumatol Suppl 1995; 101:83-9. [PMID: 7747137 DOI: 10.3109/03009749509100906] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- P L van Lent
- Department of Rheumatology, University Hospital St. Radboud, Nijmegen, The Netherlands
| | | | | | | | | | | |
Collapse
|
32
|
Abstract
T cell-mediated suppression is an established phenomenon, but its underlying mechanisms are obscure. An in vitro system was used to test the possibility that anergic T cells can act as specific suppressor cells. Anergic human T cells caused inhibition of antigen-specific and allospecific T cell proliferation. In order for the inhibition to occur, the anergic T cells had to be specific for the same antigen-presenting cells (APCs) as the T cells that were suppressed. The mechanism of this suppression appears to be competition for the APC surface and for locally produced interleukin-2.
Collapse
Affiliation(s)
- G Lombardi
- Department of Immunology, Royal Postgraduate Medical School, London, UK
| | | | | | | |
Collapse
|
33
|
Affiliation(s)
- D B Drachman
- Department of Neurology, Johns Hopkins University, Baltimore, Maryland 21287-7519
| | | | | | | |
Collapse
|
34
|
Kool J, Gerrits-Boeye MY, Severijnen AJ, Hazenberg MP. Immunohistology of joint inflammation induced in rats by cell wall fragments of Eubacterium aerofaciens. Scand J Immunol 1992; 36:497-506. [PMID: 1519039 DOI: 10.1111/j.1365-3083.1992.tb02965.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
After a single intraperitoneal injection of cell wall fragments of Eubacterium aerofaciens, a main resident from the human intestinal flora, an acute arthritis develops within 2 days which is followed by a chronic arthritis that lasts at least 90 days. In an earlier report the histological appearance of the joint inflammation during this period has been described. In this study we investigated in more detail the cell types that are involved in the development of arthritis by using cell-type-specific monoclonal antibodies in an immunohistological assay. In the acute phase of arthritis, T-helper cells appeared in the synovial tissue together with ED1-positive (ED1+) and ED3-positive (ED3+) macrophages. After a temporary decline at day 12 all macrophage subsets, as well as T-helper cells, reappeared or increased again at day 33. Later, in the chronic phase (days 47-90), an increased number of ED1-positive (ED1+) cells in the synovial tissue and a decreased number of ED2-positive (ED2+) cells in the synovial lining was the most prominent finding when compared with control rats. These results indicate that, apart from T lymphocytes, macrophages also play an important role in the development and continuation of chronic arthritis in this model.
Collapse
Affiliation(s)
- J Kool
- Department of Immunology, Erasmus University, Rotterdam, The Netherlands
| | | | | | | |
Collapse
|