1
|
Kumari S, Mak M, Poh YC, Tohme M, Watson N, Melo M, Janssen E, Dustin M, Geha R, Irvine DJ. Cytoskeletal tension actively sustains the migratory T-cell synaptic contact. EMBO J 2020; 39:e102783. [PMID: 31894880 PMCID: PMC7049817 DOI: 10.15252/embj.2019102783] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 11/12/2019] [Accepted: 11/18/2019] [Indexed: 01/06/2023] Open
Abstract
When migratory T cells encounter antigen-presenting cells (APCs), they arrest and form radially symmetric, stable intercellular junctions termed immunological synapses which facilitate exchange of crucial biochemical information and are critical for T-cell immunity. While the cellular processes underlying synapse formation have been well characterized, those that maintain the symmetry, and thereby the stability of the synapse, remain unknown. Here we identify an antigen-triggered mechanism that actively promotes T-cell synapse symmetry by generating cytoskeletal tension in the plane of the synapse through focal nucleation of actin via Wiskott-Aldrich syndrome protein (WASP), and contraction of the resultant actin filaments by myosin II. Following T-cell activation, WASP is degraded, leading to cytoskeletal unraveling and tension decay, which result in synapse breaking. Thus, our study identifies and characterizes a mechanical program within otherwise highly motile T cells that sustains the symmetry and stability of the T cell-APC synaptic contact.
Collapse
Affiliation(s)
- Sudha Kumari
- Koch Institute of Integrative Research, MIT, Cambridge, MA, USA.,Ragon Institute of Harvard, MIT and MGH, Cambridge, MA, USA
| | - Michael Mak
- Department of Mechanical Engineering, MIT, Cambridge, MA, USA
| | - Yeh-Chuin Poh
- Koch Institute of Integrative Research, MIT, Cambridge, MA, USA.,Department of Mechanical Engineering, MIT, Cambridge, MA, USA
| | - Mira Tohme
- Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Nicki Watson
- Whitehead Institute of Biomedical Research, Cambridge, MA, USA
| | - Mariane Melo
- Koch Institute of Integrative Research, MIT, Cambridge, MA, USA.,Ragon Institute of Harvard, MIT and MGH, Cambridge, MA, USA
| | - Erin Janssen
- Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Michael Dustin
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
| | - Raif Geha
- Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Darrell J Irvine
- Koch Institute of Integrative Research, MIT, Cambridge, MA, USA.,Ragon Institute of Harvard, MIT and MGH, Cambridge, MA, USA.,Department of Biological Engineering, MIT, Cambridge, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| |
Collapse
|
2
|
Lingel H, Brunner-Weinzierl MC. CTLA-4 (CD152): A versatile receptor for immune-based therapy. Semin Immunol 2019; 42:101298. [DOI: 10.1016/j.smim.2019.101298] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 08/05/2019] [Indexed: 12/31/2022]
|
3
|
Brunner-Weinzierl MC, Rudd CE. CTLA-4 and PD-1 Control of T-Cell Motility and Migration: Implications for Tumor Immunotherapy. Front Immunol 2018; 9:2737. [PMID: 30542345 PMCID: PMC6277866 DOI: 10.3389/fimmu.2018.02737] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/06/2018] [Indexed: 12/12/2022] Open
Abstract
CTLA-4 is a co-receptor on T-cells that controls peripheral tolerance and the development of autoimmunity. Immune check-point blockade (ICB) uses monoclonal antibodies (MAbs) to block the binding of inhibitory receptors (IRs) to their natural ligands. A humanized antibody to CTLA-4 was first approved clinically followed by the use of antibody blockade against PD-1 and its ligand PD-L1. Effective anti-tumor immunity requires the activation of tumor-specific effector T-cells, the blockade of regulatory cells and the migration of T-cells into the tumor. Here, we review data implicating CTLA-4 and PD-1 in the motility of T-cells with a specific reference to the potential exploitation of these pathways for more effective tumor infiltration and eradication.
Collapse
Affiliation(s)
- Monika C Brunner-Weinzierl
- Department of Experimental Pediatrics, University Hospital, Health Campus Immunology, Infectiology and Inflammation, Otto-von-Guericke-University, Magdeburg, Germany
| | - Christopher E Rudd
- Research Center-Maisonneuve-Rosemont Hospital (CRHMR), Montreal, QC, Canada.,Département de Medicine, Université de Montréal, Montreal, QC, Canada
| |
Collapse
|
4
|
Sury K, Perazella MA, Shirali AC. Cardiorenal complications of immune checkpoint inhibitors. Nat Rev Nephrol 2018; 14:571-588. [DOI: 10.1038/s41581-018-0035-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
5
|
Honda T, Egen JG, Lämmermann T, Kastenmüller W, Torabi-Parizi P, Germain RN. Tuning of antigen sensitivity by T cell receptor-dependent negative feedback controls T cell effector function in inflamed tissues. Immunity 2014; 40:235-247. [PMID: 24440150 DOI: 10.1016/j.immuni.2013.11.017] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 11/22/2013] [Indexed: 12/24/2022]
Abstract
Activated T cells must mediate effector responses sufficiently to clear pathogens while avoiding excessive tissue damage. Here we have combined dynamic intravital microscopy with ex vivo assessments of T cell cytokine responses to generate a detailed spatiotemporal picture of CD4(+) T cell effector regulation in the skin. In response to antigen, effector T cells arrested transiently on antigen-presenting cells, briefly producing cytokine and then resuming migration. Antigen recognition led to upregulation of the programmed death-1 (PD-1) glycoprotein by T cells and blocking its canonical ligand, programmed death-ligand 1 (PD-L1), lengthened the duration of migration arrest and cytokine production, showing that PD-1 interaction with PD-L1 is a major negative feedback regulator of antigen responsiveness. We speculate that the immune system employs T cell recruitment, transient activation, and rapid desensitization to allow the T cell response to rapidly adjust to changes in antigen presentation and minimize collateral injury to the host.
Collapse
Affiliation(s)
- Tetsuya Honda
- Lymphocyte Biology Section, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jackson G Egen
- Lymphocyte Biology Section, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tim Lämmermann
- Lymphocyte Biology Section, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wolfgang Kastenmüller
- Lymphocyte Biology Section, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Parizad Torabi-Parizi
- Lymphocyte Biology Section, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ronald N Germain
- Lymphocyte Biology Section, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| |
Collapse
|
6
|
Ridolfi L, Ridolfi R. Anti-CTLA-4 therapy in melanoma: role of ipilimumab (MDX-010). ACTA ACUST UNITED AC 2014. [DOI: 10.1586/edm.09.11] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
|
7
|
Ma K, Lv S, Liu B, Liu Z, Luo Y, Kong W, Xu Q, Feng J, Wang X. CTLA4-IgG ameliorates homocysteine-accelerated atherosclerosis by inhibiting T-cell overactivation in apoE(-/-) mice. Cardiovasc Res 2012; 97:349-59. [PMID: 23118130 DOI: 10.1093/cvr/cvs330] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS Cytotoxic T lymphocyte antigen 4 (CTLA4) exerts inhibitory effects on T-cell activation by competition with CD28. In this study, we investigated the effect of CTLA4-IgG on homocysteine (Hcy)-induced T-cell activation and potential signal pathways involved in atherosclerotic formation. METHODS AND RESULTS The CD28 signal was significantly amplified by Hcy treatment in splenic T cells and hyperhomocysteinaemia (HHcy)-accelerated plaques in apolipoprotein E-deficient (apoE(-/-)) mice. As a major competitor of CD28, CTLA4-IgG (abatacept) pretreatment, 100 μg/week, in apoE(-/-) mice could reverse 2- and 4-week HHcy-accelerated atherosclerosis. Furthermore, the membrane level of CTLA4 was decreased and the endocytosis level was increased by HHcy. Endocytosed CTLA4 molecules by Hcy were in large vesicles, colocalized with lysosomes and endosomes. Hcy-increased CTLA4 endocytosis and secretion of inflammatory cytokines in T cells were blocked by CTLA4-IgG and the PI3K inhibitor LY294002. Blocking the CD28 signal pathway in T cells significantly decreased Hcy-promoted macrophage migration. CONCLUSION These results illustrate a novel mechanism of CD28-dependent T-cell costimulation involved in HHcy-accelerated atherosclerosis, which extends the pharmacological application of CTLA4-IgG for atherosclerosis.
Collapse
Affiliation(s)
- Kongyang Ma
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Peking University, Beijing 100191, PR China
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Płoski R, Szymański K, Bednarczuk T. The genetic basis of graves' disease. Curr Genomics 2012; 12:542-63. [PMID: 22654555 PMCID: PMC3271308 DOI: 10.2174/138920211798120772] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 08/05/2011] [Accepted: 08/15/2011] [Indexed: 01/09/2023] Open
Abstract
The presented comprehensive review of current knowledge about genetic factors predisposing to Graves’ disease (GD) put emphasis on functional significance of observed associations. In particular, we discuss recent efforts aimed at refining diseases associations found within the HLA complex and implicating HLA class I as well as HLA-DPB1 loci. We summarize data regarding non-HLA genes such as PTPN22, CTLA4, CD40, TSHR and TG which have been extensively studied in respect to their role in GD. We review recent findings implicating variants of FCRL3 (gene for FC receptor-like-3 protein), SCGB3A2 (gene for secretory uteroglobin-related protein 1- UGRP1) as well as other unverified possible candidate genes for GD selected through their documented association with type 1 diabetes mellitus: Tenr–IL2–IL21, CAPSL (encoding calcyphosine-like protein), IFIH1(gene for interferon-induced helicase C domain 1), AFF3, CD226 and PTPN2. We also review reports on association of skewed X chromosome inactivation and fetal microchimerism with GD. Finally we discuss issues of genotype-phenotype correlations in GD.
Collapse
Affiliation(s)
- Rafał Płoski
- Department of Medical Genetics, Centre for Biostructure, Medical University of Warsaw, Poland
| | | | | |
Collapse
|
9
|
Bugelski PJ, Martin PL. Concordance of preclinical and clinical pharmacology and toxicology of therapeutic monoclonal antibodies and fusion proteins: cell surface targets. Br J Pharmacol 2012; 166:823-46. [PMID: 22168282 PMCID: PMC3417412 DOI: 10.1111/j.1476-5381.2011.01811.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 10/14/2011] [Accepted: 11/28/2011] [Indexed: 12/20/2022] Open
Abstract
Monoclonal antibodies (mAbs) and fusion proteins directed towards cell surface targets make an important contribution to the treatment of disease. The purpose of this review was to correlate the clinical and preclinical data on the 15 currently approved mAbs and fusion proteins targeted to the cell surface. The principal sources used to gather data were: the peer reviewed Literature; European Medicines Agency 'Scientific Discussions'; and the US Food and Drug Administration 'Pharmacology/Toxicology Reviews' and package inserts (United States Prescribing Information). Data on the 15 approved biopharmaceuticals were included: abatacept; abciximab; alefacept; alemtuzumab; basiliximab; cetuximab; daclizumab; efalizumab; ipilimumab; muromonab; natalizumab; panitumumab; rituximab; tocilizumab; and trastuzumab. For statistical analysis of concordance, data from these 15 were combined with data on the approved mAbs and fusion proteins directed towards soluble targets. Good concordance with human pharmacodynamics was found for mice receiving surrogates or non-human primates (NHPs) receiving the human pharmaceutical. In contrast, there was poor concordance for human pharmacodynamics in genetically deficient mice and for human adverse effects in all three test systems. No evidence that NHPs have superior predictive value was found.
Collapse
Affiliation(s)
- Peter J Bugelski
- Biologics Toxicology, Janssen Research & Development, division of Johnson & Johnson Pharmaceutical Research & Development, LLC, Radnor, PA 19087, USA
| | | |
Collapse
|
10
|
Walker LSK, Sansom DM. The emerging role of CTLA4 as a cell-extrinsic regulator of T cell responses. Nat Rev Immunol 2011; 11:852-63. [PMID: 22116087 DOI: 10.1038/nri3108] [Citation(s) in RCA: 526] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The T cell protein cytotoxic T lymphocyte antigen 4 (CTLA4) was identified as a crucial negative regulator of the immune system over 15 years ago, but its mechanisms of action are still under debate. It has long been suggested that CTLA4 transmits an inhibitory signal to the cells that express it. However, not all the available data fit with a cell-intrinsic function for CTLA4, and other studies have suggested that CTLA4 functions in a T cell-extrinsic manner. Here, we discuss the data for and against the T cell-intrinsic and -extrinsic functions of CTLA4.
Collapse
Affiliation(s)
- Lucy S K Walker
- MRC Centre for Immune Regulation, University of Birmingham Medical School, Birmingham, UK.
| | | |
Collapse
|
11
|
T-cell signalling in antiretroviral-treated, aviraemic HIV-1-positive individuals is present in a raised state of basal activation that contributes to T-cell hyporesponsiveness. AIDS 2011; 25:1981-6. [PMID: 21811141 DOI: 10.1097/qad.0b013e32834b35a9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Successful antiretroviral therapy (ART) suppresses plasma HIV-1 RNA below detection limits, reducing the chronic insult to the immune systems of infected individuals and supporting a degree of immunological recovery. However, the surface phenotypic profile of T cells in ART-treated patients does not resemble that of healthy, uninfected individuals, but rather shows upregulation of proteins associated with an exhausted immune system. We sought to address whether aviraemic HIV-1 infection, therefore, contributed to long-term alterations in intracellular signalling events within the T cells of infected individuals that contributed to the exhausted phenotype. DESIGN A flow cytometric approach was employed to assess levels of phosphorylation within T-cell signalling proteins in ART-treated HIV-1-positive patients and HIV-negative individuals. METHODS The relative phosphorylation levels of extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinases (JNK), p38, zeta-chain-associated protein kinase 70 (ZAP70), linker of activated T cells, SLP76, nuclear factor kappaB were measured within resting and stimulated CD4(+) and CD8(+) T cells from aviraemic HIV-1-positive and healthy individuals by intracellular staining and flow cytometric analysis. RESULTS Basal levels of phospho-ZAP70, phospho-ERK and phospho-JNK were two-fold to three-fold higher in HIV-1-positive individuals compared with healthy controls, with phospho-p38 also showing a tendency to increase in HIV-1-positive individuals. Interestingly, in contrast to healthy controls, peripheral blood mononuclear cells from aviraemic, infected individuals were refractory to stimulation with IL-2 and CD3/CD28 showing no enhancement of phosphorylation. CONCLUSION CD4(+) and CD8(+) T cells from HIV-1-positive individuals are poorly responsive to direct stimulation through the T-cell receptor due to chronically raised basal activation levels of intracellular signalling molecules.
Collapse
|
12
|
Fife BT, Pauken KE. The role of the PD-1 pathway in autoimmunity and peripheral tolerance. Ann N Y Acad Sci 2011; 1217:45-59. [DOI: 10.1111/j.1749-6632.2010.05919.x] [Citation(s) in RCA: 240] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
|
13
|
Hugues S. Dynamics of dendritic cell-T cell interactions: a role in T cell outcome. Semin Immunopathol 2010; 32:227-38. [PMID: 20607241 DOI: 10.1007/s00281-010-0211-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Accepted: 05/28/2010] [Indexed: 01/19/2023]
Abstract
Antigen-specific dendritic cells (DC)-T cell encounters occur in lymph nodes (LNs) and are essential for the induction of both priming and tolerance. In both cases, T cells are rapidly activated and proliferate. However, the subsequent outcome of T cell activation depends on the modulation of different DC- and T cell-intrinsic signals. Recent advances in two-photon (2P) microscopy have furthered our understanding regarding the complex choreography of DCs and T cells in intact LNs, and established differences in the dynamics of DC-T cell contacts during priming and tolerance induction. The mechanisms that favour DC-T cell encounters, as well as the contribution of the frequency and the duration of such encounters in dictating the T cell response, are discussed in this review.
Collapse
Affiliation(s)
- Stéphanie Hugues
- Department of Pathology, University of Geneva Medical School, Geneva, Switzerland.
| |
Collapse
|
14
|
Diepolder H, Obst R. Making antigen invisible: a coinhibitory molecule regulates the interaction between T cells and dendritic cells. Expert Rev Vaccines 2010; 9:243-7. [PMID: 20218851 DOI: 10.1586/erv.09.164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Antigen-specific downregulation of T-cell effector function is critical for maintaining self-tolerance but it can promote pathogen persistence in chronic infections; consequently, the restoration of T-cell effector functions is a major goal of therapeutic vaccines against chronic viral infections and malignancies. Recently, a number of T-cell inhibitory receptors, most prominently programmed death-1 (PD-1) and cytotoxic T-lymphocyte antigen-4, have been described that are associated with T-cell exhaustion and tolerance. Blocking these receptors can restore T-cell function and, depending on the model, lead to autoimmune disease or successful viral elimination. Antibodies to PD-1 and cytotoxic T-lymphocyte antigen-4 are currently being tested in clinical trials in several malignant diseases and chronic hepatitis C as they are promising candidates for combination with both prophylactic and therapeutic vaccines. Given the central role of T-cell inhibitory receptors in the regulation of immune responses, understanding their molecular mode of action is of major importance. In the report from Fife and colleagues, two-photon laser scanning microscopy of mouse lymphoid and peripheral tissue has been employed to study the interaction of tolerized PD-1-expressing T cells with antigen-bearing dendritic cells in vivo. While tolerized T cells moved freely and did not make prolonged contacts with dendritic cells, addition of an antibody that blocked the interaction between PD-1 and its ligand PD-L1 lowered T-cell motility, enhanced T-cell-dendritic cell contacts and caused autoimmune disease in the nonobese diabetic mouse model of autoimmune diabetes. The authors conclude that PD-1-PD-L1 interactions mediate peripheral tolerance by inhibiting T-cell receptor-induced stop signals.
Collapse
Affiliation(s)
- Helmut Diepolder
- Institute for Immunology and Medical Department II, Medical Faculty, Ludwig-Maximilians-University, Goethestr. 31, 80336 München, Germany.
| | | |
Collapse
|
15
|
Rush CM, Millington OR, Hutchison S, Bryson K, Brewer JM, Garside P. Characterization of CD4+ T-cell-dendritic cell interactions during secondary antigen exposure in tolerance and priming. Immunology 2010; 128:463-71. [PMID: 19930039 DOI: 10.1111/j.1365-2567.2009.03124.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Despite the recent advances in our understanding of the dynamics of the cellular interactions associated with the induction of immune responses, comparatively little is known about the in vivo behaviour of antigen-experienced T cells upon secondary antigen exposure in either priming or tolerance. Such information would provide an insight into the functional mechanisms employed by memory T cells of distinct phenotypes and provide invaluable knowledge of how a specific tolerogenic or immunogenic state is maintained. Using real-time imaging to follow the in vivo motility of naïve, primed and tolerized CD4(+) T cells and their interactions with dendritic cells (DCs), we demonstrate that each of these distinct functional phenotypes is associated with specific patterns of behaviour. We show that antigen-experienced CD4(+) T cells, whether primed or tolerized, display inherently slower migration, making many short contacts with DCs in the absence of antigen. Following secondary exposure to antigen, primed T cells increase their intensity or area of interaction with DCs whereas contacts between DCs and tolerized T cells are reduced. Importantly, this was not associated with alterations in the contact time between DCs and T cells, suggesting that T cells that have previously encountered antigen are more effective at surveying DCs. Thus, our studies are the first to demonstrate that naïve, primed and tolerized T cells show distinct behaviours before and after secondary antigen-encounter, providing a novel mechanism for the increased immune surveillance associated with memory T cells. These findings have important consequences for many immunotherapeutics, which aim to manipulate secondary immune responses.
Collapse
Affiliation(s)
- Catherine M Rush
- Centre for Biophotonics, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | | | | | | | | | | |
Collapse
|
16
|
Downey JS, Imami N. T-cell dysfunction in HIV-1 infection: targeting the inhibitors. ACTA ACUST UNITED AC 2010. [DOI: 10.2217/hiv.09.51] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Since AIDS emerged almost three decades ago, there have been considerable advances in the field of antiretroviral chemotherapy for those chronically infected with HIV-1. However, this therapy is noncurative and as our understanding of HIV-1 immunopathogenesis increases, it is becoming apparent that further therapeutic interventions are required to reverse the devastating effects of HIV-1 infection worldwide. While viral clearance remains the principle goal of HIV-1 treatment, this article describes immunotherapeutic options that target the immunological effects of the virus, to reduce its presence in the body and counteract viral-induced T-cell dysfunction and inhibition. Such approaches may augment existing antiretroviral therapy to overturn virus-induced T-cell anergy in the infected host, improving levels of immune control that reduce viremia and decrease the rate of transmission.
Collapse
Affiliation(s)
- Jocelyn S Downey
- Department of Immunology, Imperial College London, Chelsea & Westminster Hospital, 369 Fulham Road, London, SW10 9NH, UK
| | - Nesrina Imami
- Department of Immunology, Imperial College London, Chelsea & Westminster Hospital, 369 Fulham Road, London, SW10 9NH, UK
| |
Collapse
|
17
|
Fife BT, Pauken KE, Eagar TN, Obu T, Wu J, Tang Q, Azuma M, Krummel MF, Bluestone JA. Interactions between PD-1 and PD-L1 promote tolerance by blocking the TCR-induced stop signal. Nat Immunol 2009; 10:1185-92. [PMID: 19783989 PMCID: PMC2778301 DOI: 10.1038/ni.1790] [Citation(s) in RCA: 571] [Impact Index Per Article: 38.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Accepted: 08/12/2009] [Indexed: 12/13/2022]
Abstract
Programmed death 1 (PD-1) is an inhibitory molecule expressed on activated T cells; however, the biological context in which PD-1 controls T cell tolerance remains unclear. Using two-photon laser-scanning microscopy, we show here that unlike naive or activated islet antigen-specific T cells, tolerized islet antigen-specific T cells moved freely and did not swarm around antigen-bearing dendritic cells (DCs) in pancreatic lymph nodes. Inhibition of T cell antigen receptor (TCR)-driven stop signals depended on continued interactions between PD-1 and its ligand, PD-L1, as antibody blockade of PD-1 or PD-L1 resulted in lower T cell motility, enhanced T cell-DC contacts and caused autoimmune diabetes. Blockade of the immunomodulatory receptor CTLA-4 did not alter T cell motility or abrogate tolerance. Thus, PD-1-PD-L1 interactions maintain peripheral tolerance by mechanisms fundamentally distinct from those of CTLA-4.
Collapse
Affiliation(s)
- Brian T Fife
- UCSF Diabetes Center, Department of Medicine, University of California, San Francisco, California, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Abstract
SUMMARY T-cell activation is mediated by antigen-specific signals from the TCRzeta/CD3 and CD4-CD8-p56lck complexes in combination with additional co-signals provided by coreceptors such as CD28, inducible costimulator (ICOS), cytotoxic T-lymphocyte antigen-4 (CTLA-4), programmed death (PD-1), and others. CD28 and ICOS provide positive signals that promote and sustain T-cell responses, while CTLA-4 and PD-1 limit responses. The balance between stimulatory and inhibitory co-signals determines the ultimate nature of T-cell responses where response to foreign pathogen is achieved without excess inflammation and autoimmunity. In this review, we outline the current knowledge of the CD28 and CTLA-4 signaling mechanisms [involving phosphatidylinositol 3 kinase (PI3K), growth factor receptor-bound protein 2 (Grb2), Filamin A, protein kinase C theta (PKCtheta), and phosphatases] that control T-cell immunity. We also present recent findings on T-cell receptor-interacting molecule (TRIM) regulation of CTLA-4 surface expression, and a signaling pathway involving CTLA-4 activation of PI3K and protein kinase B (PKB)/AKT by which cell survival is ensured under conditions of anergy induction.
Collapse
Affiliation(s)
- Christopher E Rudd
- Department of Pathology, Cell Signalling Section, University of Cambridge, Cambridge, UK.
| | | | | |
Collapse
|
19
|
Abstract
Activation of the T-cell co-receptor cytotoxic T-lymphocyte antigen 4 (CTLA4) has a pivotal role in adjusting the threshold for T-cell activation and in preventing autoimmunity and massive tissue infiltration by T cells. Although many mechanistic models have been postulated, no single model has yet accounted for its overall function. In this Opinion article, I outline the strengths and weaknesses of the current models, and present a new 'reverse stop-signal model' to account for CTLA4 function.
Collapse
Affiliation(s)
- Christopher E Rudd
- Cell Signalling Section, Division of Immunology, Department of Pathology, Tennis Court Road, CB1 4QP Cambridge, UK.
| |
Collapse
|