1
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Gaud G, Achar S, Bourassa FXP, Davies J, Hatzihristidis T, Choi S, Kondo T, Gossa S, Lee J, Juneau P, Taylor N, Hinrichs CS, McGavern DB, François P, Altan-Bonnet G, Love PE. CD3ζ ITAMs enable ligand discrimination and antagonism by inhibiting TCR signaling in response to low-affinity peptides. Nat Immunol 2023; 24:2121-2134. [PMID: 37945821 DOI: 10.1038/s41590-023-01663-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 09/29/2023] [Indexed: 11/12/2023]
Abstract
The T cell antigen receptor (TCR) contains ten immunoreceptor tyrosine-based activation motif (ITAM) signaling sequences distributed within six CD3 subunits; however, the reason for such structural complexity and multiplicity is unclear. Here we evaluated the effect of inactivating the three CD3ζ chain ITAMs on TCR signaling and T cell effector responses using a conditional 'switch' mouse model. Unexpectedly, we found that T cells expressing TCRs containing inactivated (non-signaling) CD3ζ ITAMs (6F-CD3ζ) exhibited reduced ability to discriminate between low- and high-affinity ligands, resulting in enhanced signaling and cytokine responses to low-affinity ligands because of a previously undetected inhibitory function of CD3ζ ITAMs. Also, 6F-CD3ζ TCRs were refractory to antagonism, as predicted by a new in silico adaptive kinetic proofreading model that revises the role of ITAM multiplicity in TCR signaling. Finally, T cells expressing 6F-CD3ζ displayed enhanced cytolytic activity against solid tumors expressing low-affinity ligands, identifying a new counterintuitive approach to TCR-mediated cancer immunotherapy.
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Affiliation(s)
- Guillaume Gaud
- Hematopoiesis and Lymphocyte Biology Section, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Sooraj Achar
- Immunodynamics Section, Laboratory of Integrative Cancer Immunology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
| | - François X P Bourassa
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, Quebec, Canada
- Department of Physics, McGill University, Montréal QC, Canada
| | - John Davies
- Genitourinary Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
- Department of Safety Assessment, Genentech, Inc., San Francisco, CA, USA
| | - Teri Hatzihristidis
- Hematopoiesis and Lymphocyte Biology Section, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Seeyoung Choi
- Hematopoiesis and Lymphocyte Biology Section, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Taisuke Kondo
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Selamawit Gossa
- Viral Immunology & Intravital Imaging Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Jan Lee
- Hematopoiesis and Lymphocyte Biology Section, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Paul Juneau
- National Institutes of Health Library, Office of Research Services, National Institutes of Health, Bethesda, MD, USA
| | - Naomi Taylor
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Christian S Hinrichs
- Genitourinary Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
- Duncan and Nancy MacMillan Cancer Immunology and Metabolism Center of Excellence, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
| | - Dorian B McGavern
- Viral Immunology & Intravital Imaging Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Paul François
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, Quebec, Canada
- Mila Québec, Montréal, Quebec, Canada
| | - Grégoire Altan-Bonnet
- Immunodynamics Section, Laboratory of Integrative Cancer Immunology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Paul E Love
- Hematopoiesis and Lymphocyte Biology Section, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, Bethesda, MD, USA.
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2
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Gangopadhyay K, Roy A, Chandradasan AC, Roy S, Debnath O, SenGupta S, Chowdhury S, Das D, Das R. An evolutionary divergent thermodynamic brake in ZAP-70 fine-tunes the kinetic proofreading in T cells. J Biol Chem 2022; 298:102376. [PMID: 35970395 PMCID: PMC9486129 DOI: 10.1016/j.jbc.2022.102376] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 11/18/2022] Open
Abstract
T cell signaling starts with assembling several tyrosine kinases and adaptor proteins to the T cell receptor (TCR), following the antigen-binding to the TCR. The stability of the TCR-antigen complex and the delay between the recruitment and activation of each kinase determines the T cell response. Integration of such delays constitutes a kinetic proofreading mechanism to regulate T cell response to the antigen binding. However, the mechanism of these delays is not fully understood. Combining biochemical experiments and kinetic modelling, here we report a thermodynamic brake in the regulatory module of the tyrosine kinase ZAP-70, which determines the ligand selectivity, and may delay the ZAP-70 activation upon antigen binding to TCR. The regulatory module of ZAP-70 comprises of a tandem SH2 (tSH2) domain that binds to its ligand, doubly-phosphorylated ITAM peptide (ITAM-Y2P), in two kinetic steps: a fast step and a slow step. We show the initial encounter complex formation between the ITAM-Y2P and tSH2 domain follows a fast-kinetic step, whereas the conformational transition to the holo-state follows a slow-kinetic step. We further observed a thermodynamic penalty imposed during the second phosphate-binding event reduces the rate of structural transition to the holo-state. Phylogenetic analysis revealed the evolution of the thermodynamic brake coincides with the divergence of the adaptive immune system to the cell-mediated and humoral responses. In addition, the paralogous kinase Syk expressed in B cells does not possess such a functional thermodynamic brake, which may explain the higher basal activation and lack of ligand selectivity in Syk.
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Affiliation(s)
- Kaustav Gangopadhyay
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Arnab Roy
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Athira C Chandradasan
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Swarnendu Roy
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Olivia Debnath
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Soumee SenGupta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Subhankar Chowdhury
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Dipjyoti Das
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India.
| | - Rahul Das
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India; Centre for Advanced Functional Materials, Indian Institute of Science Education and Research Kolkata, Mohanpur, India.
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3
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Eggert J, Au-Yeung BB. Functional heterogeneity and adaptation of naive T cells in response to tonic TCR signals. Curr Opin Immunol 2021; 73:43-49. [PMID: 34653787 DOI: 10.1016/j.coi.2021.09.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 09/16/2021] [Accepted: 09/23/2021] [Indexed: 01/13/2023]
Abstract
Mature CD4+ and CD8+ T cells constitutively experience weak T cell receptor (TCR) stimulation in response to self-antigens, termed tonic (or basal) signaling. How tonic TCR signal strength impacts T cell responses to foreign antigens is an active area of investigation. Such studies rely on surrogate markers of tonic signal strength, including CD5, Ly6C, and transgenic reporters of Nr4a genes. Recent research indicates that strong tonic TCR signal strength influences basal T cell metabolism, effector differentiation, and TCR signal transduction. T cells that experience the strongest tonic TCR signaling exhibit features of T cell activation and negative regulation. These data suggest a model whereby adaptation to tonic signaling has lasting effects that alter T cell activation and differentiation.
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Affiliation(s)
- Joel Eggert
- Division of Immunology, Lowance Center for Human Immunology, Department of Medicine, Emory University School of Medicine, United States
| | - Byron B Au-Yeung
- Division of Immunology, Lowance Center for Human Immunology, Department of Medicine, Emory University School of Medicine, United States.
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4
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Reed J, Reichelt M, Wetzel SA. Lymphocytes and Trogocytosis-Mediated Signaling. Cells 2021; 10:1478. [PMID: 34204661 PMCID: PMC8231098 DOI: 10.3390/cells10061478] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/07/2021] [Accepted: 06/10/2021] [Indexed: 12/21/2022] Open
Abstract
Trogocytosis is the intercellular transfer of membrane and membrane-associated molecules. This underappreciated process has been described in a variety of biological settings including neuronal remodeling, fertilization, viral and bacterial spread, and cancer, but has been most widely studied in cells of the immune system. Trogocytosis is performed by multiple immune cell types, including basophils, macrophages, dendritic cells, neutrophils, natural killer cells, B cells, γδ T cells, and CD4+ and CD8+ αβ T cells. Although not expressed endogenously, the presence of trogocytosed molecules on cells has the potential to significantly impact an immune response and the biology of the individual trogocytosis-positive cell. Many studies have focused on the ability of the trogocytosis-positive cells to interact with other immune cells and modulate the function of responders. Less understood and arguably equally important is the impact of these molecules on the individual trogocytosis-positive cell. Molecules that have been reported to be trogocytosed by cells include cognate ligands for receptors on the individual cell, such as activating NK cell ligands and MHC:peptide. These trogocytosed molecules have been shown to interact with receptors on the trogocytosis-positive cell and mediate intracellular signaling. In this review, we discuss the impact of this trogocytosis-mediated signaling on the biology of the individual trogocytosis-positive cell by focusing on natural killer cells and CD4+ T lymphocytes.
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Affiliation(s)
- Jim Reed
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; (J.R.); (M.R.)
| | - Madison Reichelt
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; (J.R.); (M.R.)
| | - Scott A. Wetzel
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; (J.R.); (M.R.)
- Center for Environmental Health Sciences, University of Montana, Missoula, MT 59812, USA
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5
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Rudd CE. How the Discovery of the CD4/CD8-p56 lck Complexes Changed Immunology and Immunotherapy. Front Cell Dev Biol 2021; 9:626095. [PMID: 33791292 PMCID: PMC8005572 DOI: 10.3389/fcell.2021.626095] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 01/11/2021] [Indexed: 12/22/2022] Open
Abstract
The past 25 years have seen enormous progress in uncovering the receptors and signaling mechanisms on T-cells that activate their various effecter functions. Until the late 1980s, most studies on T-cells had focused on the influx of calcium and the levels of cAMP/GMP in T-cells. My laboratory then uncovered the interaction of CD4 and CD8 co-receptors with the protein-tyrosine kinase p56lck which are now widely accepted as the initiators of the tyrosine phosphorylation cascade leading to T-cell activation. The finding explained how immune recognition receptors expressed by many immune cells, which lack intrinsic catalytic activity, can transduce activation signals via non-covalent association with non-receptor tyrosine kinases. The discovery also established the concept that a protein tyrosine phosphorylation cascade operated in T-cells. In this vein, we and others then showed that the CD4- and CD8-p56lck complexes phosphorylate the TCR complexes which led to the identification of other protein-tyrosine kinases such as ZAP-70 and an array of substrates that are now central to studies in T-cell immunity. Other receptors such as B-cell receptor, Fc receptors and others were also subsequently found to use src kinases to control cell growth. In T-cells, p56lck driven phosphorylation targets include co-receptors such as CD28 and CTLA-4 and immune cell-specific adaptor proteins such as LAT and SLP-76 which act to integrate signals proximal to surface receptors. CD4/CD8-p56lck regulated events in T-cells include intracellular calcium mobilization, integrin activation and the induction of transcription factors for gene expression. Lastly, the identification of the targets of p56lck in the TCR and CD28 provided the framework for the development of chimeric antigen receptor (CAR) therapy in the treatment of cancer. In this review, I outline a history of the development of events that led to the development of the "TCR signaling paradigm" and its implications to immunology and immunotherapy.
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Affiliation(s)
- Christopher E. Rudd
- Division of Immunology-Oncology, Centre de Recherche Hôpital Maisonneuve-Rosemont (CR-HMR), Montreal, QC, Canada
- Department of Microbiology, Infection and Immunology, Faculty of Medicine, Universite de Montreal, Montreal, QC, Canada
- Division of Experimental Medicine, Department of Medicine, McGill University Health Center, McGill University, Montreal, QC, Canada
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6
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Borna S, Fabisik M, Ilievova K, Dvoracek T, Brdicka T. Mechanisms determining a differential threshold for sensing Src family kinase activity by B and T cell antigen receptors. J Biol Chem 2020; 295:12935-12945. [PMID: 32665402 DOI: 10.1074/jbc.ra120.013552] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 07/10/2020] [Indexed: 12/11/2022] Open
Abstract
Although signal transduction by immunoreceptors such as the T cell antigen receptor (TCR), B cell antigen receptor (BCR), and Fc receptors uses the same schematic and similar molecules, the threshold and the fine-tuning are set differently for each receptor. One manifestation of these differences is that inhibition of Src family kinases (SFK) blocks TCR but not BCR signaling. SFKs are key kinases phosphorylating immunoreceptor tyrosine-based activation motifs (ITAM) in both these receptors. However, it has been proposed that in B cells, downstream kinase SYK can phosphorylate ITAM sequences independently of SFK, allowing it to compensate for the loss of SFK activity, whereas its T cell paralog ZAP-70 is not capable of this compensation. To test this proposal, we examined signaling in SYK- and ZAP-70-deficient B and T cell lines expressing SYK or ZAP-70. We also analyzed signal transduction in T cells expressing BCR or B cells expressing part of the TCR complex. We show that when compared with ZAP-70, SYK lowered the threshold for SFK activity necessary to initiate antigen receptor signaling in both T and B cells. However, neither SYK nor ZAP-70 were able to initiate signaling independently of SFK. We further found that additional important factors are involved in setting this threshold. These include differences between the antigen receptor complexes themselves and the spatial separation of the key transmembrane adaptor protein LAT from the TCR. Thus, immunoreceptor sensing of SFK activity is a complex process regulated at multiple levels.
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Affiliation(s)
- Simon Borna
- Laboratory of Leukocyte Signaling, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic; Faculty of Science, Charles University, Prague, Czech Republic
| | - Matej Fabisik
- Laboratory of Leukocyte Signaling, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic; Faculty of Science, Charles University, Prague, Czech Republic
| | - Kristyna Ilievova
- Laboratory of Leukocyte Signaling, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic; Faculty of Science, Charles University, Prague, Czech Republic
| | - Tomas Dvoracek
- Laboratory of Leukocyte Signaling, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Tomas Brdicka
- Laboratory of Leukocyte Signaling, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic.
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7
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Keller HR, Kim HK, Jo Y, Gress RE, Hong C, Park JH. The Abundance and Availability of Cytokine Receptor IL-2Rβ (CD122) Constrain the Lymphopenia-Induced Homeostatic Proliferation of Naive CD4 T Cells. THE JOURNAL OF IMMUNOLOGY 2020; 204:3227-3235. [PMID: 32393513 DOI: 10.4049/jimmunol.1901276] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 04/17/2020] [Indexed: 12/18/2022]
Abstract
Lymphopenia-induced homeostatic proliferation (LIP) is a critical mechanism for restoring T cell immunity upon lymphodepleting insults or infections. LIP is primarily driven by homeostatic cytokines, such as IL-7 and IL-15, but not all T cells respond with the same efficiency to homeostatic proliferative cues. Although CD8 T cells vigorously proliferate under lymphopenic conditions, naive CD4 T cells are substantially impaired in their response to homeostatic cytokines, and they fail to fully expand. In this study, we show that the availability of IL-2Rβ (CD122), which is a receptor subunit shared by IL-2 and IL-15, affects both the cytokine responsiveness and the LIP of naive CD4 T cells in the mouse. The enumeration of surface IL-2Rβ molecules on murine naive CD4 and naive CD8 T cells revealed a 5-fold difference in IL-2Rβ abundance. Notably, it was the limited availability of IL-2Rβ that impaired CD4 T cell responsiveness to IL-15 and suppressed their LIP. As such, forced IL-2Rβ expression on CD4 T cells by transgenesis bestowed IL-15 responsiveness onto naive CD4 T cells, which thus acquired the ability to undergo robust LIP. Collectively, these results identify IL-2Rβ availability as a new regulatory mechanism to control cytokine responsiveness and the homeostatic proliferation of murine CD4 T cells.
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Affiliation(s)
- Hilary R Keller
- Experimental Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.,Department of Surgery, Guthrie Robert Packer Hospital, Sayre, PA 18840
| | - Hye Kyung Kim
- Experimental and Transplantation Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892; and
| | - Yuna Jo
- Department of Anatomy, Pusan National University School of Medicine, Yangsan 50612, South Korea
| | - Ronald E Gress
- Experimental and Transplantation Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892; and
| | - Changwan Hong
- Experimental Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892; .,Department of Anatomy, Pusan National University School of Medicine, Yangsan 50612, South Korea
| | - Jung-Hyun Park
- Experimental Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892;
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8
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Neier SC, Ferrer A, Wilton KM, Smith SEP, Kelcher AMH, Pavelko KD, Canfield JM, Davis TR, Stiles RJ, Chen Z, McCluskey J, Burrows SR, Rossjohn J, Hebrink DM, Carmona EM, Limper AH, Kappes DJ, Wettstein PJ, Johnson AJ, Pease LR, Daniels MA, Neuhauser C, Gil D, Schrum AG. The early proximal αβ TCR signalosome specifies thymic selection outcome through a quantitative protein interaction network. Sci Immunol 2020; 4:4/32/eaal2201. [PMID: 30770409 DOI: 10.1126/sciimmunol.aal2201] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 01/17/2019] [Indexed: 12/18/2022]
Abstract
During αβ T cell development, T cell antigen receptor (TCR) engagement transduces biochemical signals through a protein-protein interaction (PPI) network that dictates dichotomous cell fate decisions. It remains unclear how signal specificity is communicated, instructing either positive selection to advance cell differentiation or death by negative selection. Early signal discrimination might occur by PPI signatures differing qualitatively (customized, unique PPI combinations for each signal), quantitatively (graded amounts of a single PPI series), or kinetically (speed of PPI pathway progression). Using a novel PPI network analysis, we found that early TCR-proximal signals distinguishing positive from negative selection appeared to be primarily quantitative in nature. Furthermore, the signal intensity of this PPI network was used to find an antigen dose that caused a classic negative selection ligand to induce positive selection of conventional αβ T cells, suggesting that the quantity of TCR triggering was sufficient to program selection outcome. Because previous work had suggested that positive selection might involve a qualitatively unique signal through CD3δ, we reexamined the block in positive selection observed in CD3δ0 mice. We found that CD3δ0 thymocytes were inhibited but capable of signaling positive selection, generating low numbers of MHC-dependent αβ T cells that expressed diverse TCR repertoires and participated in immune responses against infection. We conclude that the major role for CD3δ in positive selection is to quantitatively boost the signal for maximal generation of αβ T cells. Together, these data indicate that a quantitative network signaling mechanism through the early proximal TCR signalosome determines thymic selection outcome.
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Affiliation(s)
- Steven C Neier
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA.,Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Alejandro Ferrer
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Katelynn M Wilton
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA.,Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN, USA.,Medical Scientist Training Program, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Stephen E P Smith
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - April M H Kelcher
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA.,Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN, USA.,Department of Neurology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Kevin D Pavelko
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Jenna M Canfield
- Molecular Pathogenesis and Therapeutics PhD Graduate Program, University of Missouri, Columbia, MO, USA
| | - Tessa R Davis
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Robert J Stiles
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Zhenjun Chen
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, Victoria 3010, Australia
| | - James McCluskey
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Scott R Burrows
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland 4006, Australia.,School of Medicine, University of Queensland, Brisbane, Queensland 4006, Australia
| | - Jamie Rossjohn
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.,ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia.,Institute of Infection and Immunity, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK
| | - Deanne M Hebrink
- Thoracic Diseases Research Unit, Division of Pulmonary Critical Care and Internal Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Eva M Carmona
- Thoracic Diseases Research Unit, Division of Pulmonary Critical Care and Internal Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Andrew H Limper
- Thoracic Diseases Research Unit, Division of Pulmonary Critical Care and Internal Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Dietmar J Kappes
- Blood Cell Development and Cancer Keystone, Immune Cell Development and Host Defense Program, Fox Chase Cancer Center, Philadelphia, PA, USA
| | - Peter J Wettstein
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA.,Department of Surgery, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Aaron J Johnson
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA.,Department of Neurology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Larry R Pease
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Mark A Daniels
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, USA.,Department of Surgery, School of Medicine, University of Missouri, Columbia, MO, USA
| | | | - Diana Gil
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, USA. .,Department of Surgery, School of Medicine, University of Missouri, Columbia, MO, USA.,Department of Bioengineering, College of Engineering, University of Missouri, Columbia, MO, USA
| | - Adam G Schrum
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, USA. .,Department of Surgery, School of Medicine, University of Missouri, Columbia, MO, USA.,Department of Bioengineering, College of Engineering, University of Missouri, Columbia, MO, USA
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9
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Brennick CA, George MM, Srivastava PK, Karandikar SH. Prediction of cancer neoepitopes needs new rules. Semin Immunol 2020; 47:101387. [PMID: 31952902 DOI: 10.1016/j.smim.2020.101387] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 01/01/2020] [Indexed: 12/30/2022]
Abstract
Tumors are immunogenic and the non-synonymous point mutations harbored by tumors are a source of their immunogenicity. Immunologists have long been enamored by the idea of synthetic peptides corresponding to mutated epitopes (neoepitopes) as specific "vaccines" against tumors presenting those neoepitopes in context of MHC I. Tumors may harbor hundreds of point mutations and it would require effective prediction algorithms to identify candidate neoepitopes capable of eliciting potent tumor-specific CD8+ T cell responses. Our current understanding of MHC I-restricted epitopes come from the observance of CD8+ T cell responses against viral (vaccinia, lymphocytic choriomeningitis etc.) and model (chicken ovalbumin, hen egg lysozyme etc.) antigens. Measurable CD8+ T cell responses elicited by model or viral antigens are always directed against epitopes possessing strong binding affinity for the restricting MHC I alleles. Immense collective effort to develop methodologies combining genomic sequencing, bioinformatics and traditional immunological techniques to identify neoepitopes with strong binding affinity to MHC I has only yielded inaccurate prediction algorithms. Additionally, new evidence has emerged suggesting that neoepitopes, which unlike the epitopes of viral or model antigens have closely resembling wild-type counterparts, may not necessarily demonstrate strong affinity to MHC I. Our bearing need recalibration.
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Affiliation(s)
- Cory A Brennick
- Department of Immunology, Carole and Ray Neag Comprehensive Cancer Center, University of Connecticut School of Medicine, Farmington, CT, 06030, USA.
| | - Mariam M George
- Department of Immunology, Carole and Ray Neag Comprehensive Cancer Center, University of Connecticut School of Medicine, Farmington, CT, 06030, USA.
| | - Pramod K Srivastava
- Department of Immunology, Carole and Ray Neag Comprehensive Cancer Center, University of Connecticut School of Medicine, Farmington, CT, 06030, USA.
| | - Sukrut H Karandikar
- Department of Immunology, Carole and Ray Neag Comprehensive Cancer Center, University of Connecticut School of Medicine, Farmington, CT, 06030, USA.
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10
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Clark K, Yau J, Bloom A, Wang J, Venzon DJ, Suzuki M, Pasquet L, Compton BJ, Cardell SL, Porcelli SA, Painter GF, Zajonc DM, Berzofsky JA, Terabe M. Structure-Function Implications of the Ability of Monoclonal Antibodies Against α-Galactosylceramide-CD1d Complex to Recognize β-Mannosylceramide Presentation by CD1d. Front Immunol 2019; 10:2355. [PMID: 31649670 PMCID: PMC6794452 DOI: 10.3389/fimmu.2019.02355] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 09/18/2019] [Indexed: 11/17/2022] Open
Abstract
iNKT cells are CD1d-restricted T cells recognizing lipid antigens. The prototypic iNKT cell-agonist α-galactosylceramide (α-GalCer) alongside compounds with similar structures induces robust proliferation and cytokine production of iNKT cells and protects against cancer in vivo. Monoclonal antibodies (mAbs) that detect CD1d-α-GalCer complexes have provided critical information for understanding of antigen presentation of iNKT cell agonists. Although most iNKT cell agonists with antitumor properties are α-linked glycosphingolipids that can be detected by anti-CD1d-α-GalCer mAbs, β-ManCer, a glycolipid with a β-linkage, induces strong antitumor immunity via mechanisms distinct from those of α-GalCer. In this study, we unexpectedly discovered that anti-CD1d-α-GalCer mAbs directly recognized β-ManCer-CD1d complexes and could inhibit β-ManCer stimulation of iNKT cells. The binding of anti-CD1d-α-GalCer mAb with β-ManCer-CD1d complexes was also confirmed by plasmon resonance and could not be explained by α-anomer contamination. The binding of anti-CD1d-α-GalCer mAb was also observed with CD1d loaded with another β-linked glycosylceramide, β-GalCer (C26:0). Detection with anti-CD1d-α-GalCer mAbs indicates that the interface of the β-ManCer-CD1d complex exposed to the iNKT cell TCR can assume a structure like that of CD1d-α-GalCer, despite its disparate carbohydrate structure. These results suggest that certain β-linked monoglycosylceramides can assume a structural display similar to that of CD1d-α-GalCer and that the data based on anti-CD1d-α-GalCer binding should be interpreted with caution.
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Affiliation(s)
- Katharine Clark
- Vaccine Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, United States
| | - Jessica Yau
- Vaccine Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, United States
| | - Anja Bloom
- Vaccine Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, United States
| | - Jing Wang
- Division of Immune Regulation, La Jolla Institute for Allergy and Immunology, La Jolla, CA, United States
| | - David J Venzon
- Biostatistics and Data Management Section, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, United States
| | - Motoshi Suzuki
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute (NHLBI), NIH, Bethesda, MD, United States
| | - Lise Pasquet
- Vaccine Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, United States
| | - Benjamin J Compton
- The Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand
| | - Susanna L Cardell
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Steven A Porcelli
- Department of Microbiology and Immunology and Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Gavin F Painter
- The Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand
| | - Dirk M Zajonc
- Division of Immune Regulation, La Jolla Institute for Allergy and Immunology, La Jolla, CA, United States.,Department of Internal Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Jay A Berzofsky
- Vaccine Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, United States
| | - Masaki Terabe
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, United States
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11
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Suboptimal stimulation by weak agonist epitope variants does not drive dysfunction of HIV-1-specific cytotoxic T lymphocyte clones. AIDS 2019; 33:1565-1574. [PMID: 31306165 DOI: 10.1097/qad.0000000000002259] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
OBJECTIVE To assess whether weakly recognized epitope variants induce anergy in HIV-1-specific CD8 T lymphocyte (CTL) clones as a mechanism of dysfunction. DESIGN HIV-1-specific CTL clones were exposed to suboptimally recognized epitope variants, and screened for anergy and other T-cell dysfunction markers, and subsequent capability to kill target cells bearing index epitope. METHODS In addition to the optimally recognized index epitope, two suboptimally recognized epitope variants were selected based on titration curves for killing of peptide-labeled target cells by three HIV-1-specific CTL clones targeting the epitopes SLYNTVATL (Gag 77-85, A02-restricted), RPAEPVPLQL (Rev 66-75, B07-restricted), and KRWIIMGLNK (Gag 263-272, B27-restricted). Consequences of suboptimal stimulation were assessed by cytokine secretion, gene expression, and capacity to kill index epitope-labeled target cells upon rechallenge. RESULTS Suboptimal recognition of epitope variants reduced cytokine production by CTL similarly to reduction in killing of target cells. Gene expression profiles after suboptimal stimulation demonstrated no patterns consistent with T-cell dysfunction due to anergy, exhaustion, or apoptosis. Preexposure of CTL to epitope variants had no discernable impact on their subsequent capacity to kill index epitope-bearing target cells. CONCLUSION Our data explore the hypothesis that poorly recognized epitope variants not only facilitate HIV-1 evasion of CTL recognition, but also induce CTL dysfunction through suboptimal signaling causing anergy. However, the results do not suggest that suboptimal signaling induces anergy (or exhaustion or apoptosis), indicating that the major role of CTL epitope variation is likely viral escape.
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12
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Wu SW, Li L, Wang Y, Xiao Z. CTL-Derived Exosomes Enhance the Activation of CTLs Stimulated by Low-Affinity Peptides. Front Immunol 2019; 10:1274. [PMID: 31275303 PMCID: PMC6593274 DOI: 10.3389/fimmu.2019.01274] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 05/20/2019] [Indexed: 01/07/2023] Open
Abstract
Cytotoxic T cells (CTLs) bind to peptides presented by MHC I (pMHC) through T cell receptors of various affinities. Low-affinity CTLs are important for the control of intracellular pathogens and cancers; however, the mechanisms by which these lower affinity CTLs are activated and maintained are not well understood. We recently discovered that fully activated CTLs stimulated by strong-affinity peptides in the presence of IL-12 are able to secrete exosomes that, in turn, stimulate bystander CTLs without requiring the presence of antigen. We hypothesized that exosomes secreted by high-affinity CTLs could strengthen the activation of low-affinity CTLs. Naive OT-I CD8+ cells were stimulated with altered N4 peptides of different affinities in the presence or absence of Exo. The presence of Exo preferentially increased cell proliferation and enhanced the production of IFNγ in CTLs stimulated by low-affinity peptides. The expression of granzyme B (GZB) was augmented in all affinities, with higher GZB production in low-affinity stimulated CTLs than in high-affinity stimulated ones. Exosomes promoted the rapid activation of low-affinity CTLs, which remained responsive to exosomes for a prolonged duration. Unexpectedly, exosomes could be induced quickly (24 h) following CTL activation and at a higher quantity per cell than later (72 h). While exosome protein profiles vary significantly between early exosomes and their later-derived counterparts, both appear to have similar downstream functions. These results reveal a potential mechanism for fully activated CTLs in activating lower-affinity CTLs that may have important implications in boosting the function of low-affinity CTLs in immunotherapy for cancers and chronic viral infections.
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Affiliation(s)
- Shu-Wei Wu
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, United States
| | - Lei Li
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, United States
| | - Yan Wang
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, United States
| | - Zhengguo Xiao
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, United States
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13
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Tischer DK, Weiner OD. Light-based tuning of ligand half-life supports kinetic proofreading model of T cell signaling. eLife 2019; 8:42498. [PMID: 30947808 PMCID: PMC6488292 DOI: 10.7554/elife.42498] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 04/03/2019] [Indexed: 11/30/2022] Open
Abstract
T cells are thought to discriminate self from foreign peptides by converting small differences in ligand binding half-life into large changes in cell signaling. Such a kinetic proofreading model has been difficult to test directly, as existing methods of altering ligand binding half-life also change other potentially important biophysical parameters, most notably the mechanical stability of the receptor-ligand interaction. Here we develop an optogenetic approach to specifically tune the binding half-life of a chimeric antigen receptor without changing other binding parameters and provide direct evidence of kinetic proofreading in T cell signaling. This half-life discrimination is executed in the proximal signaling pathway, downstream of ZAP70 recruitment and upstream of diacylglycerol accumulation. Our methods represent a general tool for temporal and spatial control of T cell signaling and extend the reach of optogenetics to probe pathways where the individual molecular kinetics, rather than the ensemble average, gates downstream signaling.
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Affiliation(s)
- Doug K Tischer
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States.,Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Orion David Weiner
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States
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14
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Yousefi OS, Günther M, Hörner M, Chalupsky J, Wess M, Brandl SM, Smith RW, Fleck C, Kunkel T, Zurbriggen MD, Höfer T, Weber W, Schamel WW. Optogenetic control shows that kinetic proofreading regulates the activity of the T cell receptor. eLife 2019; 8:42475. [PMID: 30947807 PMCID: PMC6488296 DOI: 10.7554/elife.42475] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 03/05/2019] [Indexed: 12/18/2022] Open
Abstract
The immune system distinguishes between self and foreign antigens. The kinetic proofreading (KPR) model proposes that T cells discriminate self from foreign ligands by the different ligand binding half-lives to the T cell receptor (TCR). It is challenging to test KPR as the available experimental systems fall short of only altering the binding half-lives and keeping other parameters of the interaction unchanged. We engineered an optogenetic system using the plant photoreceptor phytochrome B (PhyB) as a ligand to selectively control the dynamics of ligand binding to the TCR by light. This opto-ligand-TCR system was combined with the unique property of PhyB to continuously cycle between the binding and non-binding states under red light, with the light intensity determining the cycling rate and thus the binding duration. Mathematical modeling of our experimental datasets showed that indeed the ligand-TCR interaction half-life is the decisive factor for activating downstream TCR signaling, substantiating KPR.
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Affiliation(s)
- O Sascha Yousefi
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Matthias Günther
- Division of Theoretical Systems Biology, German Cancer Research Center, Heidelberg, Germany.,BioQuant Center, University of Heidelberg, Heidelberg, Germany
| | - Maximilian Hörner
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Julia Chalupsky
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany.,Center for Chronic Immunodeficiency, Medical Center Freiburg and Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Maximilian Wess
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Simon M Brandl
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Robert W Smith
- Laboratory of Systems and Synthetic Biology, Wageningen University and Research, Wageningen, Netherlands
| | - Christian Fleck
- Laboratory of Systems and Synthetic Biology, Wageningen University and Research, Wageningen, Netherlands
| | - Tim Kunkel
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Matias D Zurbriggen
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany.,Institute of Synthetic Biology and Cluster of Excellence on Plant Sciences, University of Düsseldorf, Düsseldorf, Germany
| | - Thomas Höfer
- Division of Theoretical Systems Biology, German Cancer Research Center, Heidelberg, Germany.,BioQuant Center, University of Heidelberg, Heidelberg, Germany
| | - Wilfried Weber
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Wolfgang Wa Schamel
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany.,Laboratory of Systems and Synthetic Biology, Wageningen University and Research, Wageningen, Netherlands
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15
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van den Heuvel H, Heutinck KM, van der Meer-Prins EMW, Franke-van Dijk MEI, van Miert PPMC, Zhang X, Ten Berge IJM, Claas FHJ. The avidity of cross-reactive virus-specific T cells for their viral and allogeneic epitopes is variable and depends on epitope expression. Hum Immunol 2017; 79:39-50. [PMID: 29100943 DOI: 10.1016/j.humimm.2017.10.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 10/30/2017] [Accepted: 10/30/2017] [Indexed: 10/18/2022]
Abstract
Virus-specific T cells can recognize allogeneic HLA (allo-HLA) through cross-reactivity of their T-cell receptor (TCR). In a transplantation setting, such allo-HLA cross-reactivity may contribute to harmful immune responses towards the allograft, provided that the cross-reactive T cells get sufficiently activated upon recognition of the allo-HLA. An important determinant of T-cell activation is TCR avidity, which to date, has remained largely unexplored for allo-HLA-cross-reactive virus-specific T cells. For this purpose, cold target inhibition assays were performed using allo-HLA-cross-reactive virus-specific memory CD8+ T-cell clones as responders, and syngeneic cells loaded with viral peptide and allogeneic cells as hot (radioactively-labeled) and cold (non-radioactively-labeled) targets. CD8 dependency of the T-cell responses was assessed using interferon γ (IFNγ) enzyme-linked immunosorbent assay (ELISA) in the presence and absence of CD8-blocking antibodies. At high viral-peptide loading concentrations, T-cell clones consistently demonstrated lower avidity for allogeneic versus viral epitopes, but at suboptimal concentrations the opposite was observed. In line, anti-viral reactivity was CD8 independent at high, but not at suboptimal viral-peptide-loading concentrations. The avidity of allo-HLA-cross-reactive virus-specific memory CD8+ T cells is therefore highly dependent on epitope expression, and as a consequence, can be both higher and lower for allogeneic versus viral targets under different (patho)physiological conditions.
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Affiliation(s)
- Heleen van den Heuvel
- Department of Immunohaematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands.
| | - Kirstin M Heutinck
- Department of Experimental Immunology, Academic Medical Centre, Amsterdam, The Netherlands; Renal Transplant Unit, Department of Internal Medicine, Division of Internal Medicine, Academic Medical Centre, Amsterdam, The Netherlands
| | - Ellen M W van der Meer-Prins
- Department of Immunohaematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands
| | - Marry E I Franke-van Dijk
- Department of Immunohaematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands
| | - Paula P M C van Miert
- Department of Immunohaematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands
| | - Xiaoqian Zhang
- Department of Immunohaematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands
| | - Ineke J M Ten Berge
- Renal Transplant Unit, Department of Internal Medicine, Division of Internal Medicine, Academic Medical Centre, Amsterdam, The Netherlands
| | - Frans H J Claas
- Department of Immunohaematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands
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16
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Infectious pathogens may trigger specific allo-HLA reactivity via multiple mechanisms. Immunogenetics 2017; 69:631-641. [PMID: 28718002 PMCID: PMC5537314 DOI: 10.1007/s00251-017-0989-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 04/18/2017] [Indexed: 12/21/2022]
Abstract
Transplant recipients can be sensitized against allo-HLA antigens by previous transplantation, blood transfusion, or pregnancy. While there is growing awareness that multiple components of the immune system can act as effectors of the alloresponse, the role of infectious pathogen exposure in triggering sensitization and allograft rejection has remained a matter of much debate. Here, we describe that exposure to pathogens may enhance the immune response to allogeneic HLA antigens via different pathways. The potential role of allo-HLA cross-reactivity of virus-specific memory T cells, activation of innate immunity leading to a more efficient induction of the adaptive alloimmune response by antigen-presenting cells, and bystander activation of existing memory B cell activation will be discussed in this review.
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17
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Malissen B, Bongrand P. Early T cell activation: integrating biochemical, structural, and biophysical cues. Annu Rev Immunol 2015; 33:539-61. [PMID: 25861978 DOI: 10.1146/annurev-immunol-032414-112158] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
T cells carry out the formidable task of identifying small numbers of foreign antigenic peptides rapidly and specifically against a very noisy environmental background of endogenous self-peptides. Early steps in T cell activation have thus fascinated biologists and are among the best-studied models of cell stimulation. This remarkable process, critical in adaptive immune responses, approaches and even seems to exceed the limitations set by the physical laws ruling molecular behavior. Despite the enormous amount of information concerning the nature of molecules involved in the T cell antigen receptor (TCR) signal transduction network, and the description of the nanoscale organization and real-time analysis of T cell responses, the general principles of information gathering and processing remain incompletely understood. Here we review currently accepted key data on TCR function, discuss the limitations of current research strategies, and suggest a novel model of TCR triggering and a few promising ways of going further into the integration of available data.
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Affiliation(s)
- Bernard Malissen
- Centre d'Immunologie de Marseille-Luminy and Centre d'Immunophénomique, Aix-Marseille Université, INSERM U1104 and US012, CNRS UMR7280 and UMS3367, 13288 Marseille Cedex 09, France;
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18
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Sauer EL, Cloake NC, Greer JM. Taming the TCR: antigen-specific immunotherapeutic agents for autoimmune diseases. Int Rev Immunol 2015; 34:460-85. [PMID: 25970132 DOI: 10.3109/08830185.2015.1027822] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Current treatments for autoimmune diseases are typically non-specific anti-inflammatory agents that affect not only the autoreactive cells but also the parts of the immune system that are required to maintain health. There is a need for the development of antigen-specific therapeutic agents that can effectively prevent the autoimmune attack while leaving the rest of the immune system functioning as normal. The simplest way to achieve this is using the autoantigen itself as a tolerizing agent; however, there is some risk involved with administering a potentially pathogenic antigen. In this review, we focus instead on the development and use of modified T cell receptor (TCR) ligands, in which the peptide ligand is modified to change the response by the T cell from a disease inducing to a protective response, and still retain the antigen-specificity necessary to target the autoreactive T cells. We review the use of modified TCR ligands as therapeutic agents in animal models of autoimmunity and in human autoimmune disease, and finally consider how they need to be improved in order to use them effectively in patients with autoimmune disease.
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Affiliation(s)
- Evan L Sauer
- a UQ Centre for Clinical Research , The University of Queensland , Brisbane , Queensland , Australia
| | - Nancy C Cloake
- a UQ Centre for Clinical Research , The University of Queensland , Brisbane , Queensland , Australia
| | - Judith M Greer
- a UQ Centre for Clinical Research , The University of Queensland , Brisbane , Queensland , Australia
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19
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Scrutinizing calcium flux oscillations in T lymphocytes to deduce the strength of stimulus. Sci Rep 2015; 5:7760. [PMID: 25585590 PMCID: PMC4293621 DOI: 10.1038/srep07760] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 12/11/2014] [Indexed: 01/13/2023] Open
Abstract
The capture and activation of individual T cells on functionalised surfaces enables real-time analyses of the magnitude and rhythm of intracellular calcium release. Application of Haarlet transformations generate a calcium flux ‘threshold’, with the frequency of the ‘threshold crossings’ correlating with the strength of the original T cell stimulus. These findings represent a new method to evaluate graduations in T cell activation in real time, and at a single-cell level.
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20
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Suzuki R, Scheffel J, Rivera J. New insights on the signaling and function of the high-affinity receptor for IgE. Curr Top Microbiol Immunol 2015; 388:63-90. [PMID: 25553795 DOI: 10.1007/978-3-319-13725-4_4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Clustering of the high-affinity receptor for immunoglobulin E (FcεRI) through the interaction of receptor-bound immunoglobulin E (IgE) antibodies with their cognate antigen is required to couple IgE antibody production to cellular responses and physiological consequences. IgE-induced responses through FcεRI are well known to defend the host against certain infectious agents and to lead to unwanted allergic responses to normally innocuous substances. However, the cellular and/or physiological response of individuals that produce IgE antibodies may be markedly different and such antibodies (even to the same antigenic epitope) can differ in their antigen-binding affinity. How affinity variation in the interaction of FcεRI-bound IgE antibodies with antigen is interpreted into cellular responses and how the local environment may influence these responses is of interest. In this chapter, we focus on recent advances that begin to unravel how FcεRI distinguishes differences in the affinity of IgE-antigen interactions and how such discrimination along with surrounding environmental stimuli can shape the (patho) physiological response.
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Affiliation(s)
- Ryo Suzuki
- Molecular Immunology Section, Laboratory of Molecular Immunogenetics, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
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21
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Single β³-amino acid substitutions to MOG peptides suppress the development of experimental autoimmune encephalomyelitis. J Neuroimmunol 2014; 277:67-76. [PMID: 25454728 DOI: 10.1016/j.jneuroim.2014.09.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 09/17/2014] [Accepted: 09/30/2014] [Indexed: 12/12/2022]
Abstract
CD4(+) T-cells play a key role in the pathogenesis of multiple sclerosis (MS). Altered peptide ligands capable of modulating T-cell autoreactivity are considered a promising strategy for development of antigen-specific therapies for MS. Since peptides are inherently unstable, the current study explored single β-amino acid substitution as a means of stabilizing an epitope of myelin oligodendrocyte glycoprotein. β-Amino acid substitution at position 44, the major T-cell receptor contact residue, increased the half-life of active metabolites. Vaccination with one altered peptide, MOG44βF, conferred protection from EAE, decreased T-cell autoreactivity and pro-inflammatory cytokine production. Additional studies using MOG44βF in an oral treatment regimen, administered after EAE induction, also attenuated disease severity. Thus, altered peptides such as those reported here may lead to the development of novel and more specific treatments for MS.
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22
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23
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Gangaplara A, Massilamany C, Steffen D, Reddy J. Mimicry epitope from Ehrlichia canis for interphotoreceptor retinoid-binding protein 201-216 prevents autoimmune uveoretinitis by acting as altered peptide ligand. J Neuroimmunol 2013; 263:98-107. [PMID: 24029580 DOI: 10.1016/j.jneuroim.2013.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 05/28/2013] [Accepted: 08/12/2013] [Indexed: 10/26/2022]
Abstract
We report here identification of novel mimicry epitopes for interphotoreceptor retinoid-binding protein (IRBP) 201-216, a candidate ocular antigen that causes experimental autoimmune uveoretinitis (EAU) in A/J mice. One mimicry epitope from Ehrlichia canis (EHC), designated EHC 44-59, induced cross-reactive T cells for IRBP 201-216 capable of producing T helper (Th)1 and Th17 cytokines, but failed to induce EAU in A/J mice. In addition, animals first primed with suboptimal doses of IRBP 201-216 and subsequently immunized with EHC 44-59 did not develop EAU; rather, the mimicry epitope prevented the disease induced by IRBP 201-216. However, alteration in the composition of EHC 44-59 by substituting alanine with valine at position 49, similar to the composition of IRBP 201-216, enabled the mimicry epitope to acquire uveitogenicity. The data provide new insights as to how microbes containing mimicry sequences for retinal antigens can prevent ocular inflammation by acting as naturally occurring altered peptide ligands.
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Affiliation(s)
- Arunakumar Gangaplara
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
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24
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Knudson KM, Goplen NP, Cunningham CA, Daniels MA, Teixeiro E. Low-affinity T cells are programmed to maintain normal primary responses but are impaired in their recall to low-affinity ligands. Cell Rep 2013; 4:554-65. [PMID: 23933258 DOI: 10.1016/j.celrep.2013.07.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 05/18/2013] [Accepted: 07/08/2013] [Indexed: 12/13/2022] Open
Abstract
T cell responses to low-affinity T cell receptor (TCR) ligands occur in the context of infection, tumors, and autoimmunity despite diminished TCR signal strength. The processes that enable such responses remain unclear. We show that distinct mechanisms drive effector/memory development in high- and low-affinity T cells. Low-affinity cells preferentially differentiate into memory precursors of a central memory phenotype that are interleukin (IL)-12R(lo), IL-7R(hi), and Eomes(hi). Strikingly, in contrast to naive cells, low-affinity memory cells were impaired in the response to low- but not high-affinity ligands, indicating that low-affinity cells are programmed to generate diverse immune responses while avoiding autoreactivity. Affinity and antigen dose directly correlated with IL-12R signal input and T-bet but not with Eomes expression because low- affinity signals were more potent inducers of Eomes at a high antigen dose. Our studies explain how weak antigenic signals induce complete primary immune responses and provide a framework for therapeutic intervention.
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Affiliation(s)
- Karin M Knudson
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO 65212, USA
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Petrova G, Ferrante A, Gorski J. Cross-reactivity of T cells and its role in the immune system. Crit Rev Immunol 2012; 32:349-72. [PMID: 23237510 DOI: 10.1615/critrevimmunol.v32.i4.50] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
T-cell receptors recognize peptides presented by the major histocompatibility complex (MHC) on the surface of antigen-presenting cells (APC). The ability of the T-cell receptor (TCR) to recognize more than one peptide-MHC structure defines cross-reactivity. Cross-reactivity is a documented phenomenon of the immune system whose importance is still under investigation. There are a number of rational arguments for cross-reactivity. These include the discrepancy between the theoretical high number of pathogen-derived peptides and the lower diversity of the T-cell repertoire, the need for recognition of escape variants, and the intrinsic low affinity of this receptor-ligand pair. However, quantifying the phenomenon has been difficult, and its immunological importance remains unknown. In this review, we examined the cases for and against an important role for cross reactivity. We argue that it may be an essential feature of the immune system from the point of view of biological robustness.
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Affiliation(s)
- Galina Petrova
- The Blood Research Institute, Blood Center of Wisconsin, Milwaukee, Wisconsin 53226, USA
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26
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Osborne DG, Wetzel SA. Trogocytosis results in sustained intracellular signaling in CD4(+) T cells. THE JOURNAL OF IMMUNOLOGY 2012; 189:4728-39. [PMID: 23066151 DOI: 10.4049/jimmunol.1201507] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CD4(+) T cells capture membrane and membrane-bound molecules from APCs directly from the immunological synapse in a process termed trogocytosis. The function and biological consequences of trogocytosis are largely unknown. In this study, we examine the biological significance of this phenomenon on the trogocytosis-positive T cell. We used murine fibroblasts expressing GFP-tagged I-E(k) molecules loaded with a covalently attached antigenic peptide (moth cytochrome c 88-103) to present Ag to primary TCR transgenic T cells. Using a combination of high-resolution light microscopy and flow cytometry, we show that the trogocytosed molecules are retained on the surface of the T cell in association with the TCR and elevated phosphorylated ZAP-70, phosphorylated tyrosine, and phosphorylated ERK 1/2. Through the use of the Src inhibitor PP2, we demonstrate that trogocytosed molecules directly sustain TCR signaling. In addition, after removal of APC, trogocytosis-positive cells preferentially survive in culture over several days. These novel findings suggest that trogocytosed molecules continue to engage their receptors on the T cell surface and sustain intracellular signaling leading to selective survival of these cells.
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Affiliation(s)
- Douglas G Osborne
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
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27
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Zarnitsyna V, Zhu C. T cell triggering: insights from 2D kinetics analysis of molecular interactions. Phys Biol 2012; 9:045005. [PMID: 22871794 DOI: 10.1088/1478-3975/9/4/045005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Interaction of the T cell receptor (TCR) with pathogen-derived peptide presented by the major histocompatibility complex (pMHC) molecule is central to adaptive immunity as it initiates intracellular signaling to trigger T cell response to infection. Kinetic parameters of this interaction have been under intensive investigation for more than two decades using soluble pMHCs and/or TCRs with at least one of them in the solution (three-dimensional (3D) methods). Recently, several techniques have been developed to enable kinetic analysis on live T cells with pMHCs presented by surrogate antigen presenting cells (APCs) or supported planar lipid bilayers (two-dimensional (2D) methods). Comparison of 2D versus 3D parameters reveals drastic differences with broader ranges of 2D affinities and on-rates and orders of magnitude faster 2D off-rates for functionally distinct pMHCs. Here we review new 2D data and discuss how it may impact previously developed models of T cell discrimination between pMHCs of different potencies.
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Affiliation(s)
- Veronika Zarnitsyna
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA.
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28
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Schall N, Page N, Macri C, Chaloin O, Briand JP, Muller S. Peptide-based approaches to treat lupus and other autoimmune diseases. J Autoimmun 2012; 39:143-53. [PMID: 22727561 DOI: 10.1016/j.jaut.2012.05.016] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 05/20/2012] [Indexed: 01/15/2023]
Abstract
After a long period where the potential of therapeutic peptides was let into oblivion and even dismissed, there is a revival of interest in peptides as potential drug candidates. Novel strategies for limiting metabolism and improve their bioavailability, and alternative routes of administration have emerged. This resulted in a large number of peptide-based drugs that are now being marketed in different indications. Regarding autoimmunity, successful data have been reported in numerous mouse models of autoimmune inflammation, yet relatively few clinical trials based on synthetic peptides are currently underway. This review reports on peptides that show much promises in appropriate mouse models of autoimmunity and describes in more detail clinical trials based on peptides for treating autoimmune patients. A particular emphasis is given to the 21-mer peptide P140/Lupuzor that has completed successfully phase I, phase IIa and phase IIb clinical trials for systemic lupus erythematosus.
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Affiliation(s)
- Nicolas Schall
- CNRS, Institut de Biologie Moléculaire et Cellulaire, Strasbourg, France
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29
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Piragyte I, Jun CD. Actin engine in immunological synapse. Immune Netw 2012; 12:71-83. [PMID: 22916042 PMCID: PMC3422712 DOI: 10.4110/in.2012.12.3.71] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 05/11/2012] [Accepted: 05/19/2012] [Indexed: 01/09/2023] Open
Abstract
T cell activation and function require physical contact with antigen presenting cells at a specialized junctional structure known as the immunological synapse. Once formed, the immunological synapse leads to sustained T cell receptor-mediated signalling and stabilized adhesion. High resolution microscopy indeed had a great impact in understanding the function and dynamic structure of immunological synapse. Trends of recent research are now moving towards understanding the mechanical part of immune system, expanding our knowledge in mechanosensitivity, force generation, and biophysics of cell-cell interaction. Actin cytoskeleton plays inevitable role in adaptive immune system, allowing it to bear dynamic and precise characteristics at the same time. The regulation of mechanical engine seems very complicated and overlapping, but it enables cells to be very sensitive to external signals such as surface rigidity. In this review, we focus on actin regulators and how immune cells regulate dynamic actin rearrangement process to drive the formation of immunological synapse.
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Affiliation(s)
- Indre Piragyte
- Immune Synapse Research Center and Cell Dynamics Research Center, School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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30
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Gelkop S, Weisman B, Pulak RN, Zharhary D, Isakov N. Development of unique antibodies directed against each of the six different phosphotyrosine residues within the T cell receptor CD3ζ chain. J Immunol Methods 2012; 375:129-37. [PMID: 22020291 DOI: 10.1016/j.jim.2011.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 10/02/2011] [Accepted: 10/03/2011] [Indexed: 10/16/2022]
Abstract
Signal transduction from the T cell antigen receptor (TCR)/CD3 complex involves six different immunoreceptor tyrosine-based activation motifs (ITAM) located within the cytoplasmic tails of the CD3 chains. Each ITAM possesses two conserved tyrosine residues that can undergo phosphorylation upon TCR/CD3 crosslinking and become a docking site for SH2-containing effector molecules. Specificity of the SH2 domains is determined by their ability to bind a phosphorylated tyrosine in the context of a longer peptide motif within the target protein. As a result, phosphorylation of different tyrosines within the CD3 cytoplasmic tails creates docking sites for distinct SH2-containing signaling proteins that differentially impact on the quality of the T cell response. In the present study, we prepared antibodies specific for each of the six different phosphotyrosines of the mouse CD3ζ chain. The antibodies were characterized with respect to their cross-reactivity, ability to recognize the phosphorylated versus non-phosphorylated forms of tyrosine-containing motifs, and cross-reactivity with the homologous phospho-motifs on the human CD3ζ protein. The antibodies were found to be specific and selective for phospho-CD3ζ. They can serve as useful tools for distinguishing between the six potential tyrosine phosphorylation sites on the CD3ζ chain, and for correlating the phosphorylation of specific CD3ζ tyrosine residues with activation of signaling pathways that dictate T cell differentiation into responding, anergic, or apoptotic cells.
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Affiliation(s)
- Sigal Gelkop
- Cell Biology, Department of Research & Development, Sigma-Aldrich Israel, Rehovot 76100, Israel
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31
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Distinct influences of peptide-MHC quality and quantity on in vivo T-cell responses. Proc Natl Acad Sci U S A 2012; 109:881-6. [PMID: 22223661 DOI: 10.1073/pnas.1119763109] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The strength of T-cell receptor (TCR) stimulation and subsequent T-cell response depend on a combination of peptide-major histocompatibility complex (pMHC) density and potency. By comparing two different pMHC at doses yielding similar proliferation in vivo, we have highlighted unexpected differences in the qualitative and quantitative effects of TCR ligand. Measurements of cytokine sensitivity and two-photon imaging of T cell-dendritic cell (T-DC) interactions reveal discrimination between comparably weak stimuli resulting from either decreased pMHC potency or pMHC density. In addition, TCR-induced genes in broad gene expression profiles segregate into two groups: one that responds to cumulative TCR signal and another that responds to pMHC quality, independent of quantity. These observations suggest that models of TCR ligand discrimination must account for disparate sensitivity of downstream responses to specific influences of pMHC potency.
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32
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Abstract
T cell recognition of antigen is a crucial aspect of the adaptive immune response. One of the most common means of pathogen immune evasion is mutation of T cell epitopes. T cell recognition of such ligands can result in a variety of outcomes including activation, apoptosis and anergy. The ability of a given T cell to respond to a specific peptide-MHC ligand is regulated by a number of factors, including the affinity, on- and off-rates and half-life of the TCR-peptide-MHC interaction. Interaction of T cells with low-potency ligands results in unique signaling patterns and requires engagement with a larger number of T cell receptors than agonist ligands. This review will address these aspects of T cell interaction with weak ligands and the ways in which these ligands have been utilized therapeutically.
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Zhang EY, Parker BL, Yankee TM. Gads regulates the expansion phase of CD8+ T cell-mediated immunity. THE JOURNAL OF IMMUNOLOGY 2011; 186:4579-89. [PMID: 21411729 DOI: 10.4049/jimmunol.1001604] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The Gads adaptor protein is critical for TCR-mediated Ca(2+) mobilization. We investigated the effect of Gads deficiency on the proliferation of CD8(+) T cells following peptide stimulation and in the context of infection with an intracellular pathogen. We stimulated CD8(+) T cells from Gads(+/+) OT-I and Gads(-/-) OT-I mice with cognate Ag (SIINFEKL) or altered peptide ligand. In vitro experiments revealed that Gads was required for optimal proliferation of CD8(+) T cells. This defect was most evident at the early time points of proliferation and when low doses of Ag were used as stimuli. Cell cycle analysis demonstrated that Gads(-/-) CD8(+) T cells had impaired TCR-mediated exit from the G(0) phase of the cell cycle. Furthermore, Gads(-/-) CD8(+) T cells had delayed expression of c-myc and CD69 upon the stimulation with SIINFEKL. We then investigated how Gads deficiency would impact CD8(+) T cell-mediated immunity in the context of infection with an intracellular pathogen. At early time points, Gads(+/+) and Gads(-/-) CD8(+) T cells proliferated to a similar extent, despite the fact that expression of CD69 and CD25 was reduced in the absence of Gads. After 5 d postinfection, Gads was required to sustain the expansion phase of the immune response; the peak response of Gads(-/-) cells was significantly lower than for Gads(+/+) cells. However, Gads was not required for the differentiation of naive CD8(+) T cells into memory cells. We conclude that the primary function of Gads is to regulate the sensitivity of the TCR to Ag ligation.
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Affiliation(s)
- Elizabeth Yan Zhang
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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34
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O'Konek JJ, Illarionov P, Khursigara DS, Ambrosino E, Izhak L, Castillo BF, Raju R, Khalili M, Kim HY, Howell AR, Besra GS, Porcelli SA, Berzofsky JA, Terabe M. Mouse and human iNKT cell agonist β-mannosylceramide reveals a distinct mechanism of tumor immunity. J Clin Invest 2011; 121:683-94. [PMID: 21245578 DOI: 10.1172/jci42314] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 11/17/2010] [Indexed: 01/07/2023] Open
Abstract
Type 1 or invariant NKT (iNKT) cell agonists, epitomized by α-galactosylceramide, protect against cancer largely by IFN-γ-dependent mechanisms. Here we describe what we believe to be a novel IFN-γ-independent mechanism induced by β-mannosylceramide, which also defines a potentially new class of iNKT cell agonist, with an unusual β-linked sugar. Like α-galactosylceramide, β-mannosylceramide directly activates iNKT cells from both mice and humans. In contrast to α-galactosylceramide, protection by β-mannosylceramide was completely dependent on NOS and TNF-α, neither of which was required to achieve protection with α-galactosylceramide. Moreover, at doses too low for either alone to protect, β-mannosylceramide synergized with α-galactosylceramide to protect mice against tumors. These results suggest that treatment with β-mannosylceramide provides a distinct mechanism of tumor protection that may allow efficacy where other agonists have failed. Furthermore, the ability of β-mannosylceramide to synergize with α-galactosylceramide suggests treatment with this class of iNKT agonist may provide protection against tumors in humans.
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35
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Computational analysis of T cell receptor signaling and ligand discrimination--past, present, and future. FEBS Lett 2010; 584:4814-22. [PMID: 20965176 DOI: 10.1016/j.febslet.2010.10.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 10/12/2010] [Accepted: 10/13/2010] [Indexed: 11/23/2022]
Abstract
Signaling through the T cell receptor for antigen (TCR) has been studied for years by conventional biochemical means. More recently, attempts have been made to develop computational models of signaling through this receptor, with a specific focus on understanding how this recognition system discriminates between closely related (self and non-self) ligands. Here we discuss recent advances centered on the role of feedback regulation, especially the key finding that a combination of digital and analog control circuits is fundamental to the discrimination properties of the TCR. We end by pointing to future, more biologically accurate models that incorporate spatial aspects of molecular organization in antigen-engaged T lymphocytes with this underlying biochemistry.
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36
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Mallaun M, Zenke G, Palmer E. A discrete affinity-driven elevation of ZAP-70 kinase activity initiates negative selection. J Recept Signal Transduct Res 2010; 30:430-43. [PMID: 20945976 DOI: 10.3109/10799893.2010.518151] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONTEXT Although ZAP-70 is required for T-cell development, it's unclear how this kinase controls both positive and negative selection. OBJECTIVE AND METHODS Using OT-I pre-selection thymocytes and a panel of peptide major histocompatibility complex (pMHC) ligands of defined affinity, the recruitment, phosphorylation and activity of ZAP-70 was determined at the interface with antigen-presenting cells (APCs). RESULTS pMHC ligands promoting negative selection induce a discrete elevation of ZAP-70 recruitment, phosphorylation and enzymatic activity in the thymocyte:APCs interface. DISCUSSION The quantity of ZAP-70 kinase activity per cell is a key parameter controlling the fate of a developing thymocyte since partial inhibition of ZAP-70 kinase activity converted negative into positive selection. Surprisingly, the amount of ZAP-70 enzymatic activity observed during negative selection is not controlled by differential phosphorylation of the ZAP-70 protein but rather by the total amount of T-cell receptor and co-associated ZAP-70 recruited to the thymocyte:APC interface. CONCLUSIONS These data provide evidence that a burst of ZAP-70 activity initiates the signaling pathways for negative selection.
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Affiliation(s)
- Michel Mallaun
- Laboratory of Transplantation Immunology and Nephrology, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
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37
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Castaño AP, Lin SL, Surowy T, Nowlin BT, Turlapati SA, Patel T, Singh A, Li S, Lupher ML, Duffield JS. Serum amyloid P inhibits fibrosis through Fc gamma R-dependent monocyte-macrophage regulation in vivo. Sci Transl Med 2010; 1:5ra13. [PMID: 20368175 DOI: 10.1126/scitranslmed.3000111] [Citation(s) in RCA: 170] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
New therapies that target chronic inflammation with fibrosis are urgently required. Increasing evidence points to innate activation of inflammatory cells in driving chronic organ fibrosis. Serum amyloid P is a naturally circulating soluble pattern recognition receptor, a member of the family of pentraxin proteins. It links danger-associated molecular pattern recognition to Fc gamma receptor-mediated phagocytosis. Here we show that fibrosis progression in the mouse kidney is significantly inhibited by therapeutic administration of human serum amyloid P, regulated by activating Fc gamma receptors, and dependent on inflammatory monocytes and macrophages, but not fibrocytes. Human serum amyloid P-mediated inhibition of mouse kidney fibrosis correlated with specific binding of human serum amyloid P to cell debris and with subsequent suppression of inflammatory monocytes and kidney macrophages in vitro and in vivo, and was dependent on regulated binding to activating Fc gamma receptors and interleukin-10 expression. These studies uncover previously unidentified roles for Fc gamma receptors in sterile inflammation and highlight serum amyloid P as a potential antifibrotic therapy through local generation of interleukin-10.
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Affiliation(s)
- Ana P Castaño
- Laboratory of Inflammation Research, Harvard Institutes of Medicine, 4 Blackfan Circle, Boston, MA 02115, USA
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38
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Cornwell WD, Rogers TJ. Uncoupling of T cell receptor zeta chain function during the induction of anergy by the superantigen, staphylococcal enterotoxin A. Toxins (Basel) 2010; 2:1704-17. [PMID: 22069657 PMCID: PMC3153262 DOI: 10.3390/toxins2071704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Revised: 06/17/2010] [Accepted: 06/28/2010] [Indexed: 11/16/2022] Open
Abstract
Staphylococcus aureus enterotoxins have immunomodulatory properties. In this study, we show that Staphylococcal enterotoxin A (SEA) induces a strong proliferative response in a murine T cell clone independent of MHC class II bearing cells. SEA stimulation also induces a state of hypo-responsiveness (anergy). We characterized the components of the T cell receptor (TCR) during induction of anergy by SEA. Most interestingly, TCR zeta chain phosphorylation was absent under SEA anergizing conditions, which suggests an uncoupling of zeta chain function. We characterize here a model system for studying anergy in the absence of confounding costimulatory signals.
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Affiliation(s)
- William D Cornwell
- FELS Institute, Temple University School of Medicine, 3307 North Broad Street, Philadelphia, PA 19140, USA.
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39
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Abstract
Signal transduction by the T-cell antigen receptor (TCR) is initiated by phosphorylation of conserved motifs (ITAMs) contained within the cytoplasmic domains of the invariant subunits. TCR complexes contain a total of 10 ITAMs and this unusual configuration has prompted studies of the role of specific ITAMs, or of ITAM multiplicity, in regulating TCR-directed developmental and effector responses. Here, we summarize data generated during the past two decades and discuss how these findings have in some cases resolved, and in others complicated, outstanding questions relating to the function of TCR ITAMs.
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Affiliation(s)
- Paul E Love
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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40
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Stephen TL, Tikhonova A, Riberdy JM, Laufer TM. The activation threshold of CD4+ T cells is defined by TCR/peptide-MHC class II interactions in the thymic medulla. THE JOURNAL OF IMMUNOLOGY 2009; 183:5554-62. [PMID: 19843939 DOI: 10.4049/jimmunol.0901104] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Immature thymocytes that are positively selected based upon their response to self-peptide-MHC complexes develop into mature T cells that are not overtly reactive to those same complexes. Developmental tuning is the active process through which TCR-associated signaling pathways of single-positive thymocytes are attenuated to respond appropriately to the peptide-MHC molecules that will be encountered in the periphery. In this study, we explore the mechanisms that regulate the tuning of CD4(+) single-positive T cells to MHC class II encountered in the thymic medulla. Experiments with murine BM chimeras demonstrate that tuning can be mediated by MHC class II expressed by either thymic medullary epithelial cells or thymic dendritic cells. Tuning does not require the engagement of CD4 by MHC class II on stromal cells. Rather, it is mediated by interactions between MHC class II and the TCR. To understand the molecular changes that distinguish immature hyperactive T cells from tuned mature CD4(+) T cells, we compared their responses to TCR stimulation. The altered response of mature CD4 single-positive thymocytes is characterized by the inhibition of ERK activation by low-affinity self-ligands and increased expression of the inhibitory tyrosine phosphatase SHP-1. Thus, persistent TCR engagement by peptide-MHC class II on thymic medullary stroma inhibits reactivity to self-Ags and prevents autoreactivity in the mature repertoire.
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Affiliation(s)
- Tom Li Stephen
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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41
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Sadegh-Nasseri S, Dalai SK, Korb Ferris LC, Mirshahidi S. Suboptimal engagement of the T-cell receptor by a variety of peptide-MHC ligands triggers T-cell anergy. Immunology 2009; 129:1-7. [PMID: 20002785 DOI: 10.1111/j.1365-2567.2009.03206.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
T cells recognize antigen via the T-cell receptor (TCR) and produce a spectrum of responses that range from activation to anergy or cell death. The variety of outcomes may be dictated by the strength of the signals transmitted upon cognate recognition of the TCR. The physiological outcome of TCR engagement is determined by several factors, including the avidity of the ligand for TCR, the duration of engagement, and the presence and nature of accessory molecules present on antigen-presenting cells (APCs). In this review, we discuss a model of anergy induced by presentation of low densities of peptide-major histocompatibility complex (MHC) ligand in CD4(+) T cells and compare it to anergy induced by altered peptide ligands in an effort to identify a unifying mechanism. We suggest that altered peptide ligand (APL) and low densities of agonist ligands induce anergy by engaging less than optimal numbers of TCRs. The physiological impacts of anergy in memory CD4(+) T cells are discussed.
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The novel non-mitogenic anti-CD3 antibody, mini-yCD3, delivers a partial TCR signal. Int Immunopharmacol 2009; 10:200-6. [PMID: 19913640 DOI: 10.1016/j.intimp.2009.10.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 10/20/2009] [Accepted: 10/28/2009] [Indexed: 11/23/2022]
Abstract
Previous studies indicated that a partial T-cell receptor signal delivered by non-mitogenic anti-CD3 antibodies is critical for dampening the activated T-cell response. The mini-yCD3 is a novel non-mitogenic anti-CD3 antibody based on a murine anti-human CD3 antibody yCD3. However, the mechanism by which mini-yCD3 suppresses immune responses mediated by activated T-cells remains unknown. To elucidate its mechanism, we examined the effects of the mini-yCD3 on early signaling events in T-cells. Similar to the mitogenic anti-CD3 mAb, mini-yCD3 triggered changes in the T-cell receptor (TCR). However, unlike the mitogenic anti-CD3 stimulation, mini-yCD3 was ineffective at inducing the highly phosphorylated zeta chain and tyrosine phosphorylation of the associated tyrosine kinase ZAP-70. This proximal signaling deficiency failed to mobilize detectable Ca(2+) and translocate NF-AT into the nucleus. Additionally, the non-mitogenic anti-CD3 appeared insufficient for the redistribution of TCRs into an aggregated cap, which correlated with T-cell activation.
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43
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Abstract
The series of events leading to T-cell activation following antigen recognition has been extensively investigated. Although the exact mechanisms of ligand binding and transmission of this extracellular interaction into a productive intracellular signaling sequence remains incomplete, it has been known for many years that the immunoreceptor tyrosine activation motifs (ITAMs) of the T-cell receptor (TCR):CD3 complex are required for initiation of this signaling cascade because of the recruitment and activation of multiple protein tyrosine kinases, signaling intermediates, and adapter molecules. It however remains unclear why the TCR:CD3 complex requires 10 ITAMs, while many other ITAM-containing immune receptors, such as Fc receptors (FcRs) and the B cell receptor (BCR), contain far fewer ITAMs. We have recently demonstrated that various parameters of T cell development and activation are influenced by the number, as well as location and type, of ITAMs within the TCR:CD3 complex and hence propose that the TCR is capable of 'scalable signaling' that facilitates the initiation and orchestration of diverse T-cell functions. While many of the underlying mechanisms remain hypothetical, this review intends to amalgamate what we have learned from conventional biochemical analyses regarding initiation and diversification of T-cell signaling, with more recent evidence from molecular and fluorescent microscopic analyses, to propose a broader purpose for the TCR:CD3 ITAMs. Rather than simply signal initiation, individual ITAMs may also be responsible for the differential recruitment of signaling and regulatory molecules which ultimately affects T-cell development, activation and differentiation.
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Affiliation(s)
- Clifford S Guy
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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44
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45
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Liu SD, Tomassian T, Bruhn KW, Miller JF, Poirier F, Miceli MC. Galectin-1 Tunes TCR Binding and Signal Transduction to Regulate CD8 Burst Size. THE JOURNAL OF IMMUNOLOGY 2009; 182:5283-95. [DOI: 10.4049/jimmunol.0803811] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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46
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Palmer E, Naeher D. Affinity threshold for thymic selection through a T-cell receptor–co-receptor zipper. Nat Rev Immunol 2009; 9:207-13. [DOI: 10.1038/nri2469] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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47
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Cemerski S, Das J, Giurisato E, Markiewicz MA, Allen PM, Chakraborty AK, Shaw AS. The balance between T cell receptor signaling and degradation at the center of the immunological synapse is determined by antigen quality. Immunity 2008; 29:414-22. [PMID: 18760640 DOI: 10.1016/j.immuni.2008.06.014] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Revised: 05/26/2008] [Accepted: 06/27/2008] [Indexed: 12/31/2022]
Abstract
The role of the center of the immunological synapse (the central supramolecular activation cluster or cSMAC) is controversial. One model suggests that the role of the cSMAC depends on antigen quality and can both enhance signaling and receptor downregulation, whereas a second model proposes that the sole function of the cSMAC is to downregulate signaling. An important distinction between the models is whether signaling occurs in the cSMAC. Here, we demonstrate that at early time points, signaling occurs outside the cSMAC, but occurs in the cSMAC at later time points. Additionally, we show that cSMAC formation enhances the stimulatory potency of weak agonists for the TCR. Combined with previous studies showing that cSMAC formation decreases the signaling by strong agonists, our data support a model proposing that signaling and receptor degradation both occur in the cSMAC and that the balance between signaling and degradation in the synapse is determined by antigen quality.
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Affiliation(s)
- Saso Cemerski
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
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48
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Plesa G, Snook AE, Waldman SA, Eisenlohr LC. Derivation and fluidity of acutely induced dysfunctional CD8+ T cells. THE JOURNAL OF IMMUNOLOGY 2008; 180:5300-8. [PMID: 18390711 DOI: 10.4049/jimmunol.180.8.5300] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dysfunctional CD8(+) T (T(CD8(+))) cells lacking cytokine production have been identified in many viral infections, but their genesis is not well understood. Established results indicate that such cells could be either high avidity that enter a refractory state due to overstimulation or low avidity that are only partially stimulated. Using an acute, resolving infection model that results in rapid production of dysfunctional cells, we show that this IL2 unresponsive phenotype emerges from the low end of the avidity spectrum and is characterized by broad TCR usage and a reduced proliferation rate. Furthermore, the dysfunctional population is extremely fluid, being sustained by high Ag dose but virtually eliminated following low dose boosting. Together, these results suggest that persistence of dysfunctional cells generated in this manner depends upon continual exposure to high Ag levels and that such cells may ultimately predominate if functional cells become exhausted.
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Affiliation(s)
- Gabriela Plesa
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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49
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Abstract
Multiple sclerosis (MS) is an inflammatory demyelinating disease of the CNS, characterized pathologically by a perivascular infiltrate consisting predominantly of T cells and macrophages. Although its aetiology remains unknown, several lines of evidence support the hypothesis that autoimmune mechanisms play a major role in the development of the disease. Several widely used disease-modifying agents are approved for the treatment of MS. However, these agents are only partially effective and their ability to attenuate the more progressive phases of the disease is not clear at this time. Therefore, there is a need to develop improved treatment options for MS. This article reviews the role of several novel, selective vaccine strategies that are currently under investigation, including: (i) T-cell vaccination (TCV); (ii) T-cell receptor (TCR) peptide vaccination; (iii) DNA vaccination; and (iv) altered peptide ligand (APL) vaccination. The administration of attenuated autoreactive T cells induces regulatory networks to specifically suppress pathogenic T cells in MS, a strategy named TCV. The concept of TCV was based on the experience of vaccination against aetiological agents of infectious diseases in which individuals are purposely exposed to an attenuated microbial pathogen, which then instructs the immune system to recognize and neutralize it in its virulent form. In regard to TCV, attenuated, pathogenic T cells are similarly used to instruct the immune system to recognize and neutralize disease-inducing T cells. In experimental allergic encephalomyelitis (EAE), an animal model for MS, pathogenic T cells use a strikingly limited number of variable-region elements (V region) to form TCR specific for defined autoantigens. Thus, vaccination with peptides directed against these TCR structures may induce immunoregulatory mechanisms, thereby preventing EAE. However, unlike EAE, myelin-reactive T cells derived from MS patients utilize a broad range of different V regions, challenging the clinical utility of this approach. Subsequently, the demonstration that injection of plasmid DNA encoding a reporter gene into skeletal muscle results in expression of the encoded proteins, as well as in the induction of immune responses in animal models of autoimmunity, was explored as another strategy to re-establish self-tolerance. This approach has promise for the treatment of MS and, therefore, warrants further investigation. APLs are molecules in which the native encephalitogenic peptides are modified by substitution(s) of one or a few amino acids critical for contact with the TCR. Depending on the substitution(s) at the TCR contact residues of the cognate peptide, an APL can induce immune responses that can protect against or reverse EAE. However, the heterogeneity of the immune response in MS patients requires further study to determine which patients are most likely to benefit from APL therapy. Other potential approaches for vaccines in MS include vaccination against axonal growth inhibitors associated with myelin, use of dendritic cells pulsed with specific antigens, and active vaccination against proinflammatory cytokines. Overall, vaccines for MS represent promising approaches for the treatment of this devastating disease, as well as other autoimmune diseases.
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Affiliation(s)
- Jorge Correale
- Department of Neurology, Raúl Carrea Institute for Neurological Research, Buenos Aires, Argentina.
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50
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Abstract
Although dynamic imaging technologies have provided important insights into the underlying processes responsible for T-cell activation, the processes that link antigen recognition to downstream signaling remain poorly defined. Converging lines of inquiry indicate that T-cell receptor (TCR) microclusters are the minimal structures capable of directing effective TCR signaling. Furthermore, imaging studies have determined that these structures trigger the assembly of oligomeric signaling scaffolds that contain the adapters and effectors required for T-cell activation. Existing models of T-cell activation accurately explain the sensitivity and selectivity of antigen recognition. However, these models do not account for important properties of microclusters, including their peripheral formation, size, and movement on the actin cytoskeleton. Here we examine how lipid rafts, galectin lattices, and protein scaffolds contribute to the assembly, function, and fate of TCR microclusters within immune synapses. Finally, we propose a 'mechanical segregation' model of signal initiation in which cytoskeletal forces contribute to the lateral segregation of molecules and cytoskeletal scaffolds provide a template for microclusters assembly.
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