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Kopp A, Guan J, Johnston C, Vance S, Legg J, Galson-Holt L, Thurber GM. Design of Crosslinking Antibodies For T-Cell Activation: Experimental and Computational Analysis of PD-1/CD137 Bispecific Agents. AAPS J 2024; 26:68. [PMID: 38862748 DOI: 10.1208/s12248-024-00937-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 05/20/2024] [Indexed: 06/13/2024] Open
Abstract
Bispecific and multispecific agents have become increasingly utilized in cancer treatment and immunotherapy, yet their complex design parameters present a challenge in developing successful therapeutics. Bispecifics that crosslink receptors on two opposing cells can provide specific activation of a receptor only when these cells are in close spatial proximity, such as an immune cell and cancer cell in a tumor. These agents, including T cell activating bispecifics, can avoid off-tumor toxicity through activation only in the tumor microenvironment by utilizing a tumor target to cluster T-cell receptors for a selective costimulatory signal. Here, we investigate a panel of PD-1/CD137 targeted Humabody VH domains to determine the key factors for T cell activation, such as affinity, valency, expression level, domain orientation, and epitope location. Target expression is a dominant factor determining both specificity and potency of T cell activation. Given an intrinsic expression level, the affinity can be tuned to modulate the level of activation and IC50 and achieve specificity between low and high expression levels. Changing the epitope location and linker length showed minor improvements to activation at low expression levels, but increasing the valency for the target decreased activation at all expression levels. By combining non-overlapping epitopes for the target, we achieved higher receptor activation at low expression levels. A kinetic model was able to capture these trends, offering support for the mechanistic interpretation. This work provides a framework to quantify factors for T cell activation by cell-crosslinking bispecific agents and guiding principles for the design of new agents.
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Affiliation(s)
- Anna Kopp
- Department of Chemical Engineering, University of Michigan, 2800 Plymouth Rd., Ann Arbor, Michigan, 48109, USA
| | - Jiakun Guan
- Department of Chemical Engineering, University of Michigan, 2800 Plymouth Rd., Ann Arbor, Michigan, 48109, USA
| | | | | | | | | | - Greg M Thurber
- Department of Chemical Engineering, University of Michigan, 2800 Plymouth Rd., Ann Arbor, Michigan, 48109, USA.
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, 48109, USA.
- Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan, 48109, USA.
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2
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Gao Y, Yang J, Zhang Y, Zhao Y, Zhao X, Zhang X, Zhang J, Mao L, Wang H, Wang H, Wang L. In vitro and in vivo evaluation of immune response of poly(lactic acid) nanoparticles with different end groups. Int J Biol Macromol 2023; 253:126593. [PMID: 37659499 DOI: 10.1016/j.ijbiomac.2023.126593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 08/26/2023] [Accepted: 08/27/2023] [Indexed: 09/04/2023]
Abstract
Poly(lactic acid) (PLA) has excellent properties of biodegradability and biocompatibility, which is a US Food and Drug Administration (FDA) approved biopolymer for the preparation of safe and effective vaccines, drugs, and gene delivery systems. However, there still exists a great problem whether and how the end group affects the immune response of PLA vaccines. Therefore, the aim of this study was to evaluate the in vitro and in vivo of immune response of PLA nanoparticles (NPs) with carboxyl (COOH) and ester (COOR) end groups. In vitro experiments suggested COOH NPs could promote the higher phagocytosis and activation of bone marrow dendritic cells (BMDCs) with a lower cytotoxicity. In vivo experiments showed that COOR NPs and COOH NPs could strongly elicit IgG, IgG1, and IgG2a responses both in the short and long-terms. However, the highest T cell and B cell activation, and central memory T cells response was induced by COOH NPs. In addition, the COOH NPs could significantly enhance splenocytes proliferation and cytokines secretion. Thus, the PLA with the COOH end group shows greater potential as efficient carrier materials of NPs for enhancing cellular and humoral immune responses.
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Affiliation(s)
- Yuan Gao
- State Key Laboratory of Subtropical Silviculture, College of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, Zhejiang, China; Key Laboratory of Green Process and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; Key Laboratory of Forest Plant Ecology, Ministry of Education, Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-Based Active Substances, College of Chemistry, Chemistry Engineering and Resource Utilization, Northeast Forestry University, Harbin 150040, China
| | - Jun Yang
- Beijing Tide Pharmaceutical Co., Ltd, No.8 East Rongjing Street, Beijing Econnomi Technological Development Area (BDA), Beijing 100176, China
| | - Yaru Zhang
- Key Laboratory of Green Process and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; Key Laboratory of Forest Plant Ecology, Ministry of Education, Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-Based Active Substances, College of Chemistry, Chemistry Engineering and Resource Utilization, Northeast Forestry University, Harbin 150040, China
| | - Ying Zhao
- Key Laboratory of Green Process and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; Key Laboratory of Forest Plant Ecology, Ministry of Education, Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-Based Active Substances, College of Chemistry, Chemistry Engineering and Resource Utilization, Northeast Forestry University, Harbin 150040, China
| | - Xin Zhao
- Key Laboratory of Green Process and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; Heilongjiang University of Chinese Medicine, Harbin 150036, China
| | - Xining Zhang
- Key Laboratory of Green Process and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Zhang
- Key Laboratory of Green Process and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Li Mao
- Beijing Tide Pharmaceutical Co., Ltd, No.8 East Rongjing Street, Beijing Econnomi Technological Development Area (BDA), Beijing 100176, China.
| | - Hongjun Wang
- Beijing Tide Pharmaceutical Co., Ltd, No.8 East Rongjing Street, Beijing Econnomi Technological Development Area (BDA), Beijing 100176, China.
| | - Huimei Wang
- State Key Laboratory of Subtropical Silviculture, College of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, Zhejiang, China.
| | - Lianyan Wang
- Key Laboratory of Green Process and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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3
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Ricciardelli AR, Robledo A, Fish JE, Kan PT, Harris TH, Wythe JD. The Role and Therapeutic Implications of Inflammation in the Pathogenesis of Brain Arteriovenous Malformations. Biomedicines 2023; 11:2876. [PMID: 38001877 PMCID: PMC10669898 DOI: 10.3390/biomedicines11112876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/13/2023] [Accepted: 10/16/2023] [Indexed: 11/26/2023] Open
Abstract
Brain arteriovenous malformations (bAVMs) are focal vascular lesions composed of abnormal vascular channels without an intervening capillary network. As a result, high-pressure arterial blood shunts directly into the venous outflow system. These high-flow, low-resistance shunts are composed of dilated, tortuous, and fragile vessels, which are prone to rupture. BAVMs are a leading cause of hemorrhagic stroke in children and young adults. Current treatments for bAVMs are limited to surgery, embolization, and radiosurgery, although even these options are not viable for ~20% of AVM patients due to excessive risk. Critically, inflammation has been suggested to contribute to lesion progression. Here we summarize the current literature discussing the role of the immune system in bAVM pathogenesis and lesion progression, as well as the potential for targeting inflammation to prevent bAVM rupture and intracranial hemorrhage. We conclude by proposing that a dysfunctional endothelium, which harbors the somatic mutations that have been shown to give rise to sporadic bAVMs, may drive disease development and progression by altering the immune status of the brain.
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Affiliation(s)
- Ashley R. Ricciardelli
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ariadna Robledo
- Department of Neurosurgery, University of Texas Medical Branch, Galveston, TX 77555, USA; (A.R.)
| | - Jason E. Fish
- Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 2C4, Canada;
- Laboratory Medicine & Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Peter Munk Cardiac Centre, University Health Network, Toronto, ON M5G 2N2, Canada
| | - Peter T. Kan
- Department of Neurosurgery, University of Texas Medical Branch, Galveston, TX 77555, USA; (A.R.)
| | - Tajie H. Harris
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA 22903, USA;
- Brain, Immunology, and Glia (BIG) Center, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
| | - Joshua D. Wythe
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA 22903, USA;
- Brain, Immunology, and Glia (BIG) Center, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
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4
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Orcutt-Jahns B, Emmel PC, Snyder EM, Taylor SD, Meyer AS. Multivalent, asymmetric IL-2-Fc fusions show enhanced selectivity for regulatory T cells. Sci Signal 2023; 16:eadg0699. [PMID: 37847758 PMCID: PMC10658882 DOI: 10.1126/scisignal.adg0699] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 09/21/2023] [Indexed: 10/19/2023]
Abstract
The cytokine interleukin-2 (IL-2) has the potential to treat autoimmune disease but is limited by its modest specificity toward immunosuppressive regulatory T (Treg) cells. IL-2 receptors consist of combinations of α, β, and γ chains of variable affinity and cell specificity. Engineering IL-2 to treat autoimmunity has primarily focused on retaining binding to the relatively Treg-selective, high-affinity receptor while reducing binding to the less selective, low-affinity receptor. However, we found that refining the designs to focus on targeting the high-affinity receptor through avidity effects is key to optimizing Treg selectivity. We profiled the dynamics and dose dependency of signaling responses in primary human immune cells induced by engineered fusions composed of either wild-type IL-2 or mutant forms with altered affinity, valency, and fusion to the antibody Fc region for stability. Treg selectivity and signaling response variations were explained by a model of multivalent binding and dimer-enhanced avidity-a combined measure of the strength, number, and conformation of interaction sites-from which we designed tetravalent IL-2-Fc fusions that had greater Treg selectivity in culture than do current designs. Biasing avidity toward IL2Rα with an asymmetrical multivalent design consisting of one α/β chain-binding and one α chain-binding mutant further enhanced Treg selectivity. Comparative analysis revealed that IL2Rα was the optimal cell surface target for Treg selectivity, indicating that avidity for IL2Rα may be the optimal route to producing IL-2 variants that selectively target Tregs.
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Affiliation(s)
- Brian Orcutt-Jahns
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Peter C. Emmel
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Eli M. Snyder
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Scott D. Taylor
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Aaron S. Meyer
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA
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5
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Tan ZC, Lux A, Biburger M, Varghese P, Lees S, Nimmerjahn F, Meyer AS. Mixed IgG Fc immune complexes exhibit blended binding profiles and refine FcR affinity estimates. Cell Rep 2023; 42:112734. [PMID: 37421619 PMCID: PMC10404157 DOI: 10.1016/j.celrep.2023.112734] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/21/2023] [Accepted: 06/19/2023] [Indexed: 07/10/2023] Open
Abstract
Immunoglobulin G (IgG) antibodies coordinate immune effector responses by interacting with effector cells via fragment crystallizable γ (Fcγ) receptors. The IgG Fc domain directs effector responses through subclass and glycosylation variation. Although each Fc variant has been extensively characterized in isolation, during immune responses, IgG is almost always produced in Fc mixtures. How this influences effector responses has not been examined. Here, we measure Fcγ receptor binding to mixed Fc immune complexes. Binding of these mixtures falls along a continuum between pure cases and quantitatively matches a mechanistic model, except for several low-affinity interactions mostly involving IgG2. We find that the binding model provides refined estimates of their affinities. Finally, we demonstrate that the model predicts effector cell-elicited platelet depletion in humanized mice. Contrary to previous views, IgG2 exhibits appreciable binding through avidity, though it is insufficient to induce effector responses. Overall, this work demonstrates a quantitative framework for modeling mixed IgG Fc-effector cell regulation.
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Affiliation(s)
- Zhixin Cyrillus Tan
- Bioinformatics Interdepartmental Program, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Anja Lux
- Division of Genetics, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Markus Biburger
- Division of Genetics, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Prabha Varghese
- Division of Genetics, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Stephen Lees
- Department of Bioengineering, UCLA, Los Angeles, CA 90095, USA
| | - Falk Nimmerjahn
- Division of Genetics, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Aaron S Meyer
- Bioinformatics Interdepartmental Program, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA; Department of Bioengineering, UCLA, Los Angeles, CA 90095, USA; Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, UCLA, Los Angeles, CA 90095, USA.
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6
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Cyrillus Tan Z, Lux A, Biburger M, Varghese P, Lees S, Nimmerjahn F, Meyer AS. Mixed IgG Fc immune complexes exhibit blended binding profiles and refine FcR affinity estimates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.15.528730. [PMID: 36824734 PMCID: PMC9949097 DOI: 10.1101/2023.02.15.528730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Immunoglobulin (Ig)G antibodies coordinate immune effector responses by selectively binding to target antigens and then interacting with various effector cells via the Fcγ receptors. The Fc domain of IgG can promote or inhibit distinct effector responses across several different immune cell types through variation based on subclass and Fc domain glycosylation. Extensive characterization of these interactions has revealed how the inclusion of certain Fc subclasses or glycans results in distinct immune responses. During an immune response, however, IgG is produced with mixtures of Fc domain properties, so antigen-IgG immune complexes are likely to almost always be comprised of a combination of Fc forms. Whether and how this mixed composition influences immune effector responses has not been examined. Here, we measured Fcγ receptor binding to immune complexes of mixed Fc domain composition. We found that the binding properties of the mixed-composition immune complexes fell along a continuum between those of the corresponding pure cases. Binding quantitatively matched a mechanistic binding model, except for several low-affinity interactions mostly involving IgG2. We found that the affinities of these interactions are different than previously reported, and that the binding model could be used to provide refined estimates of these affinities. Finally, we demonstrated that the binding model can predict effector-cell elicited platelet depletion in humanized mice, with the model inferring the relevant effector cell populations. Contrary to the previous view in which IgG2 poorly engages with effector populations, we observe appreciable binding through avidity, but insufficient amounts to observe immune effector responses. Overall, this work demonstrates a quantitative framework for reasoning about effector response regulation arising from IgG of mixed Fc composition. Summary points The binding behavior of mixed Fc immune complexes is a blend of the binding properties for each constituent IgG species.An equilibrium, multivalent binding model can be generalized to incorporate immune complexes of mixed Fc composition.Particularly for low-affinity IgG-Fcγ receptor interactions, immune complexes provide better estimates of affinities.The FcγR binding model predicts effector-elicited cell clearance in humanized mice.
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Affiliation(s)
- Zhixin Cyrillus Tan
- Bioinformatics Interdepartmental Program, University of California, Los Angeles (UCLA)
| | - Anja Lux
- Department of Genetics, Friedrich-Alexander-University of Erlangen-Nürnberg
| | - Markus Biburger
- Department of Genetics, Friedrich-Alexander-University of Erlangen-Nürnberg
| | - Prabha Varghese
- Department of Genetics, Friedrich-Alexander-University of Erlangen-Nürnberg
| | | | - Falk Nimmerjahn
- Department of Genetics, Friedrich-Alexander-University of Erlangen-Nürnberg
| | - Aaron S. Meyer
- Bioinformatics Interdepartmental Program, University of California, Los Angeles (UCLA),Department of Bioengineering, UCLA,Jonsson Comprehensive Cancer Center, UCLA,Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, UCLA,Corresponding author.
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7
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Tan ZC, Orcutt-Jahns BT, Meyer AS. A quantitative view of strategies to engineer cell-selective ligand binding. Integr Biol (Camb) 2021; 13:269-282. [PMID: 34931243 DOI: 10.1093/intbio/zyab019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/17/2021] [Accepted: 11/23/2021] [Indexed: 11/12/2022]
Abstract
A critical property of many therapies is their selective binding to target populations. Exceptional specificity can arise from high-affinity binding to surface targets expressed exclusively on target cell types. In many cases, however, therapeutic targets are only expressed at subtly different levels relative to off-target cells. More complex binding strategies have been developed to overcome this limitation, including multi-specific and multivalent molecules, creating a combinatorial explosion of design possibilities. Guiding strategies for developing cell-specific binding are critical to employ these tools. Here, we employ a uniquely general multivalent binding model to dissect multi-ligand and multi-receptor interactions. This model allows us to analyze and explore a series of mechanisms to engineer cell selectivity, including mixtures of molecules, affinity adjustments, valency changes, multi-specific molecules and ligand competition. Each of these strategies can optimize selectivity in distinct cases, leading to enhanced selectivity when employed together. The proposed model, therefore, provides a comprehensive toolkit for the model-driven design of selectively binding therapies.
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Affiliation(s)
- Zhixin Cyrillus Tan
- Bioinformatics Interdepartmental Program, University of California, Los Angeles, CA 90024, USA
| | - Brian T Orcutt-Jahns
- Department of Bioengineering, University of California, Los Angeles, CA 90024, USA
| | - Aaron S Meyer
- Bioinformatics Interdepartmental Program, University of California, Los Angeles, CA 90024, USA.,Department of Bioengineering, University of California, Los Angeles, CA 90024, USA.,Jonsson Comprehensive Cancer Center, University of California, Los Angeles, CA 90024, USA.,Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA 90024, USA
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8
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Tan ZC, Meyer AS. A general model of multivalent binding with ligands of heterotypic subunits and multiple surface receptors. Math Biosci 2021; 342:108714. [PMID: 34637774 PMCID: PMC8612982 DOI: 10.1016/j.mbs.2021.108714] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 07/13/2021] [Accepted: 08/30/2021] [Indexed: 10/20/2022]
Abstract
Multivalent cell surface receptor binding is a ubiquitous biological phenomenon with functional and therapeutic significance. Predicting the amount of ligand binding for a cell remains an important question in computational biology as it can provide great insight into cell-to-cell communication and rational drug design toward specific targets. In this study, we extend a mechanistic, two-step multivalent binding model. This model predicts the behavior of a mixture of different multivalent ligand complexes binding to cells expressing various types of receptors. It accounts for the combinatorially large number of interactions between multiple ligands and receptors, optionally allowing a mixture of complexes with different valencies and complexes that contain heterogeneous ligand units. We derive the macroscopic predictions and demonstrate how this model enables large-scale predictions on mixture binding and the binding space of a ligand. This model thus provides an elegant and computationally efficient framework for analyzing multivalent binding.
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Affiliation(s)
- Zhixin Cyrillus Tan
- Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, California, 90095, United States
| | - Aaron S Meyer
- Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, California, 90095, United States; Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, 90095, United States; Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Los Angeles, California, 90095, United States; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, California, 90095, United States.
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9
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Patterson-Orazem AC, Qerqez AN, Azouz LR, Ma MT, Hill SE, Ku Y, Schildmeyer LA, Maynard JA, Lieberman RL. Recombinant antibodies recognize conformation-dependent epitopes of the leucine zipper of misfolding-prone myocilin. J Biol Chem 2021; 297:101067. [PMID: 34384785 PMCID: PMC8408531 DOI: 10.1016/j.jbc.2021.101067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/02/2021] [Accepted: 08/06/2021] [Indexed: 11/11/2022] Open
Abstract
Recombinant antibodies with well-characterized epitopes and known conformational specificities are critical reagents to support robust interpretation and reproducibility of immunoassays across biomedical research. For myocilin, a protein prone to misfolding that is associated with glaucoma and an emerging player in other human diseases, currently available antibodies are unable to differentiate among the numerous disease-associated protein states. This fundamentally constrains efforts to understand the connection between myocilin structure, function, and disease. To address this concern, we used protein engineering methods to develop new recombinant antibodies that detect the N-terminal leucine zipper structural domain of myocilin and that are cross-reactive for human and mouse myocilin. After harvesting spleens from immunized mice and in vitro library panning, we identified two antibodies, 2A4 and 1G12. 2A4 specifically recognizes a folded epitope while 1G12 recognizes a range of conformations. We matured antibody 2A4 for improved biophysical properties, resulting in variant 2H2. In a human IgG1 format, 2A4, 1G12, and 2H2 immunoprecipitate full-length folded myocilin present in the spent media of human trabecular meshwork (TM) cells, and 2H2 can visualize myocilin in fixed human TM cells using fluorescence microscopy. These new antibodies should find broad application in glaucoma and other research across multiple species platforms.
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Affiliation(s)
| | - Ahlam N Qerqez
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, USA
| | - Laura R Azouz
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, USA
| | - Minh Thu Ma
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Shannon E Hill
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Yemo Ku
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Lisa A Schildmeyer
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Jennifer A Maynard
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA.
| | - Raquel L Lieberman
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA.
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10
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Poussin M, Sereno A, Wu X, Huang F, Manro J, Cao S, Carpenito C, Glasebrook A, Powell Jr DJ, Demarest SJ. Dichotomous impact of affinity on the function of T cell engaging bispecific antibodies. J Immunother Cancer 2021; 9:e002444. [PMID: 34253637 PMCID: PMC8276301 DOI: 10.1136/jitc-2021-002444] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Bispecific T cell engagers represent the majority of bispecific antibodies (BsAbs) entering the clinic to treat metastatic cancer. The ability to apply these agents safely and efficaciously in the clinic, particularly for solid tumors, has been challenging. Many preclinical studies have evaluated parameters related to the activity of T cell engaging BsAbs, but many questions remain. MAIN BODY This study investigates the impact of affinity of T cell engaging BsAbs with regards to potency, efficacy, and induction of immunomodulatory receptors/ligands using HER-2/CD3 BsAbs as a model system. We show that an IgG BsAb can be as efficacious as a smaller BsAb format both in vitro and in vivo. We uncover a dichotomous relationship between tumor-associated antigen (TAA) affinity and CD3 affinity requirements for cells that express high versus low levels of TAA. HER-2 affinity directly correlated with the CD3 engager lysis potency of HER-2/CD3 BsAbs when HER-2 receptor numbers are high (~200 K/cell), while the CD3 affinity did not impact potency until its binding affinity was extremely low (<600 nM). When HER-2 receptor numbers were lower (~20 K/cell), both HER-2 and CD3 affinity impacted potency. The high affinity anti-HER-2/low CD3 affinity BsAb also demonstrated lower cytokine induction levels in vivo and a dosing paradigm atypical of extremely high potency T cell engaging BsAbs reaching peak efficacy at doses >3 mg/kg. This data confirms that low CD3 affinity provides an opportunity for improved safety and dosing for T cell engaging BsAbs. T cell redirection also led to upregulation of Programmed cell death 1 (PD-1) and 4-1BB, but not CTLA-4 on T cells, and to Programmed death-ligand 1 (PD-L1) upregulation on HER-2HI SKOV3 tumor cells, but not on HER-2LO OVCAR3 tumor cells. Using this information, we combined anti-PD-1 or anti-4-1BB monoclonal antibodies with the HER-2/CD3 BsAb in vivo and demonstrated significantly increased efficacy against HER-2HI SKOV3 tumors via both combinations. CONCLUSIONS Overall, these studies provide an informational dive into the optimization process of CD3 engaging BsAbs for solid tumors indicating that a reduced affinity for CD3 may enable a better therapeutic index with a greater selectivity for the target tumor and a reduced cytokine release syndrome. These studies also provide an additional argument for combining T cell checkpoint inhibition and co-stimulation to achieve optimal efficacy. BACKGROUND
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Affiliation(s)
- Mathilde Poussin
- Pathology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Arlene Sereno
- Eli Lilly and Company Biotechnology Center San Diego, San Diego, California, USA
| | - Xiufeng Wu
- Eli Lilly and Company Biotechnology Center San Diego, San Diego, California, USA
| | - Flora Huang
- Eli Lilly and Company Biotechnology Center San Diego, San Diego, California, USA
| | - Jason Manro
- Eli Lilly and Company Biotechnology Center San Diego, San Diego, California, USA
| | - Shanshan Cao
- Eli Lilly and Company Biotechnology Center San Diego, San Diego, California, USA
| | - Carmine Carpenito
- Eli Lilly and Company Biotechnology Center San Diego, San Diego, California, USA
- Stelexis, New York, New York, USA
| | - Andrew Glasebrook
- Eli Lilly and Company Biotechnology Center San Diego, San Diego, California, USA
- Toralgen, San Diego, California, USA
| | - Daniel J Powell Jr
- Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Stephen J Demarest
- Eli Lilly and Company Biotechnology Center San Diego, San Diego, California, USA
- Tentarix, San Diego, California, USA
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11
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Kolawole EM, Lamb TJ, Evavold BD. Relationship of 2D Affinity to T Cell Functional Outcomes. Int J Mol Sci 2020; 21:ijms21217969. [PMID: 33120989 PMCID: PMC7662510 DOI: 10.3390/ijms21217969] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/14/2020] [Accepted: 10/23/2020] [Indexed: 12/11/2022] Open
Abstract
T cells are critical for a functioning adaptive immune response and a strong correlation exists between T cell responses and T cell receptor (TCR): peptide-loaded MHC (pMHC) binding. Studies that utilize pMHC tetramer, multimers, and assays of three-dimensional (3D) affinity have provided advancements in our understanding of T cell responses across different diseases. However, these technologies focus on higher affinity and avidity T cells while missing the lower affinity responders. Lower affinity TCRs in expanded polyclonal populations almost always constitute a significant proportion of the response with cells mediating different effector functions associated with variation in the proportion of high and low affinity T cells. Since lower affinity T cells expand and are functional, a fully inclusive view of T cell responses is required to accurately interpret the role of affinity for adaptive T cell immunity. For example, low affinity T cells are capable of inducing autoimmune disease and T cells with an intermediate affinity have been shown to exhibit an optimal anti-tumor response. Here, we focus on how affinity of the TCR may relate to T cell phenotype and provide examples where 2D affinity influences functional outcomes.
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12
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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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13
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Robinett RA, Guan N, Lux A, Biburger M, Nimmerjahn F, Meyer AS. Dissecting FcγR Regulation through a Multivalent Binding Model. Cell Syst 2018; 7:41-48.e5. [PMID: 29960887 DOI: 10.1016/j.cels.2018.05.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 03/31/2018] [Accepted: 05/22/2018] [Indexed: 10/28/2022]
Abstract
Many immune receptors transduce activation across the plasma membrane through their clustering. With Fcγ receptors (FcγRs), this clustering is driven by binding to antibodies of differing affinities that are in turn bound to multivalent antigen. As a consequence of this activation mechanism, accounting for and rationally manipulating immunoglobulin (Ig)G effector function is complicated by, among other factors, differing affinities between FcγR species and changes in the valency of antigen binding. In this study, we show that a model of multivalent receptor-ligand binding can effectively account for the contribution of IgG-FcγR affinity and immune complex valency. This model in turn enables us to make specific predictions about the effect of immune complexes of defined composition. In total, these results enable both rational immune complex design for a desired IgG effector function and the deconvolution of effector function by immune complexes.
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Affiliation(s)
- Ryan A Robinett
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ning Guan
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Anja Lux
- Division of Genetics, Department of Biology, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen 91058, Germany
| | - Markus Biburger
- Division of Genetics, Department of Biology, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen 91058, Germany
| | - Falk Nimmerjahn
- Division of Genetics, Department of Biology, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen 91058, Germany
| | - Aaron S Meyer
- Department of Bioengineering, Jonsson Comprehensive Cancer Center, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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14
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WEDAGEDERA JANAKR, BURROUGHS NJ. COMPARISON OF A DUAL STRATEGY FOR T-CELL ACTIVATION UNDER INHIBITION OF THE CD4 RECEPTOR. J BIOL SYST 2018. [DOI: 10.1142/s0218339018500158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We consider a stochastic model for T-cell activation proposed in Refs. [1] and [2] to compare the specificity and sensitivity of two different strategies for T-cell activation that utilize the history of phosphorylation of T-cell receptor (TCR). We compare these two strategies when the temporal signals/events that are essential for progressive T-cell activation are suppressed by blockade of CD4 receptor that may have caused by disease or therapeutic effects.3–6 We show that under these conditions, a threshold-strategy which is capable of maintaining a threshold (for total number of phosphorylated TCRs by time [Formula: see text]) for a further duration [Formula: see text] performs better in discriminating agonist peptides than a single-threshold strategy (reached by time [Formula: see text]) leading to T-cell activation using the Wentzell-Friedlin theory for large deviations for stochastic processes.7,8
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Affiliation(s)
- JANAK R. WEDAGEDERA
- Certara UK Limited, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield S1 2BJ, United Kingdom
| | - N. J. BURROUGHS
- Mathematics Institute and Warwick Systems, Biology Centre, University of Warwick, Coventry CV4 7AL, United Kingdom
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15
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Chen L, Tian Y, Zhan K, Chen A, Weng Z, Huang J, Li Y, Sun Y, Zheng H, Li Y. A humanized TCR retaining authentic specificity and affinity conferred potent anti-tumour cytotoxicity. Immunology 2018; 155:123-136. [PMID: 29645087 DOI: 10.1111/imm.12935] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 03/05/2018] [Accepted: 03/28/2018] [Indexed: 12/14/2022] Open
Abstract
The affinity of T-cell receptor (TCR) determines the efficacy of TCR-based immunotherapy. By using human leucocyte antigen (HLA)-A*02 transgenic mice, a TCR was generated previously specific for human tumour testis antigen peptide MAGE-A3112-120 (KVAELVHFL) HLA-A*02 complex. We developed an approach to humanize the murine TCR by replacing the mouse framework with sequences of folding optimized human TCR variable domains for retaining binding affinity. The resultant humanized TCR exhibited higher affinity and conferred better anti-tumour activity than its parent murine MAGE-A3 TCR (SRm1). In addition, the affinity of humanized TCR was enhanced further to achieve improved T-cell activation. Our studies demonstrated that the human TCR variable domain frameworks could provide support for complementarity-determining regions from a murine TCR, and retain the original binding activity. It could be used as a generic approach of TCR humanization.
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Affiliation(s)
- Lin Chen
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Ye Tian
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Kai Zhan
- XiangXue Life Sciences Research Center, XiangXue Pharmaceutical Co. Ltd, Guangzhou, China
| | - Anan Chen
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Zhiming Weng
- XiangXue Life Sciences Research Center, XiangXue Pharmaceutical Co. Ltd, Guangzhou, China
| | - Jiao Huang
- XiangXue Life Sciences Research Center, XiangXue Pharmaceutical Co. Ltd, Guangzhou, China
| | - Yanyan Li
- School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Yongjie Sun
- Institute of Health Sciences, Anhui University, Hefei, China
| | - Hongjun Zheng
- XiangXue Life Sciences Research Center, XiangXue Pharmaceutical Co. Ltd, Guangzhou, China
| | - Yi Li
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,University of Chinese Academy of Sciences, Beijing, China.,XiangXue Life Sciences Research Center, XiangXue Pharmaceutical Co. Ltd, Guangzhou, China
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16
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Perica K, Kosmides AK, Schneck JP. Linking form to function: Biophysical aspects of artificial antigen presenting cell design. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1853:781-90. [PMID: 25200637 PMCID: PMC4344884 DOI: 10.1016/j.bbamcr.2014.09.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 08/15/2014] [Accepted: 09/01/2014] [Indexed: 12/22/2022]
Abstract
Artificial antigen presenting cells (aAPCs) are engineered platforms for T cell activation and expansion, synthesized by coupling T cell activating proteins to the surface of cell lines or biocompatible particles. They can serve both as model systems to study the basic aspects of T cell signaling and translationally as novel approaches for either active or adoptive immunotherapy. Historically, these reductionist systems have not been designed to mimic the temporally and spatially complex interactions observed during endogenous T cell-APC contact, which include receptor organization at both micro- and nanoscales and dynamic changes in cell and membrane morphologies. Here, we review how particle size and shape, as well as heterogenous distribution of T cell activating proteins on the particle surface, are critical aspects of aAPC design. In doing so, we demonstrate how insights derived from endogenous T cell activation can be applied to optimize aAPC, and in turn how aAPC platforms can be used to better understand endogenous T cell stimulation. This article is part of a Special Issue entitled: Nanoscale membrane organisation and signalling.
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Affiliation(s)
- Karlo Perica
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA; Institute of Cell Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Alyssa K Kosmides
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA; Institute of Cell Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Jonathan P Schneck
- Institute of Cell Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Pathology, Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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17
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Pompano RR, Chen J, Verbus EA, Han H, Fridman A, McNeely T, Collier JH, Chong AS. Titrating T-cell epitopes within self-assembled vaccines optimizes CD4+ helper T cell and antibody outputs. Adv Healthc Mater 2014; 3:1898-908. [PMID: 24923735 PMCID: PMC4227912 DOI: 10.1002/adhm.201400137] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 05/12/2014] [Indexed: 12/14/2022]
Abstract
Epitope content plays a critical role in determining T-cell and antibody responses to vaccines, biomaterials, and protein therapeutics, but its effects are nonlinear and difficult to isolate. Here, molecular self-assembly is used to build a vaccine with precise control over epitope content, in order to finely tune the magnitude and phenotype of T helper and antibody responses. Self-adjuvanting peptide nanofibers are formed by co-assembling a high-affinity universal CD4+ T-cell epitope (PADRE) and a B-cell epitope from Staphylococcus aureus at specifiable concentrations. Increasing the PADRE concentration from micromolar to millimolar elicited bell-shaped dose-responses that are unique to different T-cell populations. Notably, the epitope ratios that maximize T follicular helper and antibody responses differed by an order of magnitude from those that maximized Th1 or Th2 responses. Thus, modular materials assembly provides a means of controlling epitope content and efficiently skewing the adaptive immune response in the absence of exogenous adjuvant; this approach may contribute to the development of improved vaccines and immunotherapies.
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Affiliation(s)
- Rebecca R. Pompano
- Department of Surgery, Committee of Immunology, University of Chicago, 5841 S. Maryland Avenue, MC5032, Chicago, IL 60637 USA
| | - Jianjun Chen
- Department of Surgery, Committee of Immunology, University of Chicago, 5841 S. Maryland Avenue, MC5032, Chicago, IL 60637 USA
| | - Emily A. Verbus
- Department of Surgery, Committee of Immunology, University of Chicago, 5841 S. Maryland Avenue, MC5032, Chicago, IL 60637 USA
| | - Huifang Han
- Department of Surgery, Committee of Immunology, University of Chicago, 5841 S. Maryland Avenue, MC5032, Chicago, IL 60637 USA
| | | | | | - Joel H. Collier
- Department of Surgery, Committee of Immunology, University of Chicago, 5841 S. Maryland Avenue, MC5032, Chicago, IL 60637 USA
| | - Anita S. Chong
- Department of Surgery, Committee of Immunology, University of Chicago, 5841 S. Maryland Avenue, MC5032, Chicago, IL 60637 USA
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18
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Castro M, van Santen HM, Férez M, Alarcón B, Lythe G, Molina-París C. Receptor Pre-Clustering and T cell Responses: Insights into Molecular Mechanisms. Front Immunol 2014; 5:132. [PMID: 24817867 PMCID: PMC4012210 DOI: 10.3389/fimmu.2014.00132] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 03/15/2014] [Indexed: 11/13/2022] Open
Abstract
T cell activation, initiated by T cell receptor (TCR) mediated recognition of pathogen-derived peptides presented by major histocompatibility complex class I or II molecules (pMHC), shows exquisite specificity and sensitivity, even though the TCR-pMHC binding interaction is of low affinity. Recent experimental work suggests that TCR pre-clustering may be a mechanism via which T cells can achieve such high sensitivity. The unresolved stoichiometry of the TCR makes TCR-pMHC binding and TCR triggering, an open question. We formulate a mathematical model to characterize the pre-clustering of T cell receptors (TCRs) on the surface of T cells, motivated by the experimentally observed distribution of TCR clusters on the surface of naive and memory T cells. We extend a recently introduced stochastic criterion to compute the timescales of T cell responses, assuming that ligand-induced cross-linked TCR is the minimum signaling unit. We derive an approximate formula for the mean time to signal initiation. Our results show that pre-clustering reduces the mean activation time. However, additional mechanisms favoring the existence of clusters are required to explain the difference between naive and memory T cell responses. We discuss the biological implications of our results, and both the compatibility and complementarity of our approach with other existing mathematical models.
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Affiliation(s)
- Mario Castro
- Grupo de Dinámica No-Lineal and Grupo Interdisciplinar de Sistemas Complejos (GISC), Escuela Técnica Superior de Ingeniería (ICAI), Universidad Pontificia Comillas , Madrid , Spain
| | - Hisse M van Santen
- Departamento de Biología Celular e Inmunología, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid , Madrid , Spain
| | - María Férez
- Departamento de Biología Celular e Inmunología, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid , Madrid , Spain
| | - Balbino Alarcón
- Departamento de Biología Celular e Inmunología, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid , Madrid , Spain
| | - Grant Lythe
- Department of Applied Mathematics, School of Mathematics, University of Leeds , Leeds , UK
| | - Carmen Molina-París
- Department of Applied Mathematics, School of Mathematics, University of Leeds , Leeds , UK
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19
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T-cell receptor affinity and avidity defines antitumor response and autoimmunity in T-cell immunotherapy. Proc Natl Acad Sci U S A 2013; 110:6973-8. [PMID: 23576742 DOI: 10.1073/pnas.1221609110] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
T cells expressing antigen-specific T-cell receptors (TCRs) can mediate effective tumor regression, but they often also are accompanied by autoimmune responses. To determine the TCR affinity threshold defining the optimal balance between effective antitumor activity and autoimmunity in vivo, we used a unique self-antigen system comprising seven human melanoma gp100(209-217)-specific TCRs spanning physiological affinities (1-100 μM). We found that in vitro and in vivo T-cell responses are determined by TCR affinity, except in one case that was compensated by substantial CD8 involvement. Strikingly, we found that T-cell antitumor activity and autoimmunity are closely coupled but plateau at a defined TCR affinity of 10 µM, likely due to diminished contribution of TCR affinity to avidity above the threshold. Together, these results suggest that a relatively low-affinity threshold is necessary for the immune system to avoid self-damage, given the close relationship between antitumor activity and autoimmunity. The low threshold, in turn, indicates that adoptive T-cell therapy treatment strategies using in vitro-generated high-affinity TCRs do not necessarily improve efficacy.
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20
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Tang JL, Schoenwald K, Potter D, White D, Sulchek T. Bifunctional Janus microparticles with spatially segregated proteins. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:10033-9. [PMID: 22624704 PMCID: PMC3428262 DOI: 10.1021/la3010079] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We present a fabrication process to create bifunctional microparticles displaying two distinct proteins that are spatially segregated onto the surface hemispheres. Silica and polystyrene microparticles with 2.0, 4.1, and 4.7 μm diameters are processed with metal deposition to form two chemically distinct and segregated hemispheres. The surface of each hemisphere is then separately derivatized with biological proteins using different chemical conjugation strategies. These bifunctional Janus particles possess biologically relevant, native conformation proteins attached to a biologically unreactive and safe substrate. They also display high densities of each type of protein which may enable a range of capabilities that monofunctional particles cannot, such as improved targeting of drugs and bioimaging agents.
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Affiliation(s)
| | | | | | - David White
- Centers for Disease Control and Prevention, Atlanta, GA 30333, George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332
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21
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Currie J, Castro M, Lythe G, Palmer E, Molina-París C. A stochastic T cell response criterion. J R Soc Interface 2012; 9:2856-70. [PMID: 22745227 PMCID: PMC3479899 DOI: 10.1098/rsif.2012.0205] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The adaptive immune system relies on different cell types to provide fast and coordinated responses, characterized by recognition of pathogenic challenge, extensive cellular proliferation and differentiation, as well as death. T cells are a subset of the adaptive immune cellular pool that recognize immunogenic peptides expressed on the surface of antigen-presenting cells by means of specialized receptors on their membrane. T cell receptor binding to ligand determines T cell responses at different times and locations during the life of a T cell. Current experimental evidence provides support to the following: (i) sufficiently long receptor–ligand engagements are required to initiate the T cell signalling cascade that results in productive signal transduction and (ii) counting devices are at work in T cells to allow signal accumulation, decoding and translation into biological responses. In the light of these results, we explore, with mathematical models, the timescales associated with T cell responses. We consider two different criteria: a stochastic one (the mean time it takes to have had N receptor–ligand complexes bound for at least a dwell time, τ, each) and one based on equilibrium (the time to reach a threshold number N of receptor–ligand complexes). We have applied mathematical models to previous experiments in the context of thymic negative selection and to recent two-dimensional experiments. Our results indicate that the stochastic criterion provides support to the thymic affinity threshold hypothesis, whereas the equilibrium one does not, and agrees with the ligand hierarchy experimentally established for thymic negative selection.
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Affiliation(s)
- James Currie
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds LS2 9JT, UK
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22
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Analysis of Cell Binding and Internalization of Multivalent PEG-Based Gene Delivery Vehicles. IEEE Trans Nanobioscience 2012; 11:54-61. [DOI: 10.1109/tnb.2011.2179555] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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23
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Cui L, Kitov PI, Completo GC, Paulson JC, Bundle DR. Supramolecular complexing of membane Siglec CD22 mediated by a polyvalent heterobifunctional ligand that templates on IgM. Bioconjug Chem 2011; 22:546-50. [PMID: 21405019 DOI: 10.1021/bc100579d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We report the synthesis and in vitro evaluation of a multivalent homing device, a polymer which contains preordered pendant groups with dual specificity, a trisaccharide moiety, which is specific for the siglec CD22, and an antibody specific hapten, nitrophenol. The device efficiently attracts antihapten IgM to the surface of human lymphoma B cells as well as to CD22-conjugated magnetic beads by mediating the formation of a ternary complex on the surface of the target.
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Affiliation(s)
- Lina Cui
- Department of Chemistry, Alberta Ingenuity Centre for Carbohydrate Science, University of Alberta , Edmonton, Alberta, Canada
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24
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Manipulating antigenic ligand strength to selectively target myelin-reactive CD4+ T cells in EAE. J Neuroimmune Pharmacol 2009; 5:176-88. [PMID: 19904613 DOI: 10.1007/s11481-009-9181-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 10/15/2009] [Indexed: 10/20/2022]
Abstract
The development of antigen-specific therapies for the selective tolerization of autoreactive T cells remains the Holy Grail for the treatment of T-cell-mediated autoimmune diseases such as multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). This quest remains elusive, however, as the numerous antigen-specific strategies targeting myelin-specific T cells over the years have failed to result in clinical success. In this review, we revisit the antigen-based therapies used in the treatment of myelin-specific CD4+ T cells in the context of the functional avidity and the strength of signal of the encephalitogenic CD4+ T cell repertoire. In light of differences in activation thresholds, we propose that autoreactive T cells are not all equal, and therefore tolerance induction strategies must incorporate ligand strength in order to be successful in treating EAE and ultimately the human disease MS.
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25
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Chervin AS, Stone JD, Holler PD, Bai A, Chen J, Eisen HN, Kranz DM. The impact of TCR-binding properties and antigen presentation format on T cell responsiveness. THE JOURNAL OF IMMUNOLOGY 2009; 183:1166-78. [PMID: 19553539 DOI: 10.4049/jimmunol.0900054] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
TCR interactions with cognate peptide-MHC (pepMHC) ligands are generally low affinity. This feature, together with the requirement for CD8/CD4 participation, has made it difficult to dissect relationships between TCR-binding parameters and T cell activation. Interpretations are further complicated when comparing different pepMHC, because these can vary greatly in stability. To examine the relationships between TCR-binding properties and T cell responses, in this study we characterized the interactions and activities mediated by a panel of TCRs that differed widely in their binding to the same pepMHC. Monovalent binding of soluble TCR was characterized by surface plasmon resonance, and T cell hybridomas that expressed these TCR, with or without CD8 coexpression, were tested for their binding of monomeric and oligomeric forms of the pepMHC and for subsequent responses (IL-2 release). The binding threshold for eliciting this response in the absence of CD8 (K(D) = 600 nM) exhibited a relatively sharp cutoff between full activity and no activity, consistent with a switchlike response to pepMHC on APCs. However, when the pepMHC was immobilized (plate bound), T cells with the lowest affinity TCRs (e.g., K(D) = 30 microM) responded, even in the absence of CD8, indicating that these TCR are signaling competent. Surprisingly, even cells that expressed high-affinity (K(D) = 16 nM) TCRs along with CD8 were unresponsive to oligomers in solution. The findings suggest that to drive downstream T cell responses, pepMHC must be presented in a form that supports formation of appropriate supramolecular clusters.
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Affiliation(s)
- Adam S Chervin
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
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Stone JD, Chervin AS, Kranz DM. T-cell receptor binding affinities and kinetics: impact on T-cell activity and specificity. Immunology 2009; 126:165-76. [PMID: 19125887 DOI: 10.1111/j.1365-2567.2008.03015.x] [Citation(s) in RCA: 257] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The interaction between the T-cell receptor (TCR) and its peptide-major histocompatibility complex (pepMHC) ligand plays a critical role in determining the activity and specificity of the T cell. The binding properties associated with these interactions have now been studied in many systems, providing a framework for a mechanistic understanding of the initial events that govern T-cell function. There have been various other reviews that have described the structural and biochemical features of TCR : pepMHC interactions. Here we provide an overview of four areas that directly impact our understanding of T-cell function, as viewed from the perspective of the TCR : pepMHC interaction: (1) relationships between T-cell activity and TCR : pepMHC binding parameters, (2) TCR affinity, avidity and clustering, (3) influence of coreceptors on pepMHC binding by TCRs and T-cell activity, and (4) impact of TCR binding affinity on antigenic peptide specificity.
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Affiliation(s)
- Jennifer D Stone
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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27
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Vollers SS, Stern LJ. Class II major histocompatibility complex tetramer staining: progress, problems, and prospects. Immunology 2008; 123:305-13. [PMID: 18251991 DOI: 10.1111/j.1365-2567.2007.02801.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The use of major histocompatibility complex (MHC) tetramers in the detection and analysis of antigen-specific T cells has become more widespread since its introduction 11 years ago. Early challenges in the application of tetramer staining to CD4+ T cells centred around difficulties in the expression of various class II MHC allelic variants and the detection of low-frequency T cells in mixed populations. As many of the technical obstacles to class II MHC tetramer staining have been overcome, the focus has returned to uncertainties concerning how oligomer valency and T-cell receptor/MHC affinity affect tetramer binding. Such issues have become more important with an increase in the number of studies relying on direct ex vivo analysis of antigen-specific CD4+ T cells. In this review we discuss which problems in class II MHC tetramer staining have been solved to date, and which matters remain to be considered.
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Affiliation(s)
- Sabrina S Vollers
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA
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28
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A comprehensive platform for ex vivo T-cell expansion based on biodegradable polymeric artificial antigen-presenting cells. Mol Ther 2008; 16:765-72. [PMID: 18334990 DOI: 10.1038/mt.2008.11] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Efficient T-cell stimulation and proliferation in response to specific antigens is a goal of immunotherapy against infectious disease and cancer. Manipulation of this response can be accomplished by adoptive immunotherapy involving the infusion of antigen-specific T-cell populations expanded ex vivo with antigen presenting cells. We mimicked physiological antigen presentation on a biodegradable microparticle constructed from poly(lactide-co-glycolide) (PLGA), a polymer system whose safety has been established for use in humans. These particles present a high density of adaptor elements for attaching both recognition ligands and co-stimulatory ligands to a biodegradable core encapsulating the cytokine interleukin-2 (IL-2). We demonstrate the utility of this system in efficient polyclonal and antigen-specific T-cell stimulation and expansion, showing that sustained release of IL-2 in the vicinity of T-cell contacts dramatically improves the stimulatory capacity of these acellular systems, as compared to the effect of exogenous addition of cytokine. This results in a 45-fold enhancement in T-cell expansion. In addition, this mode of antigen presentation skews the expansion toward the CD8(+) T-cell phenotype. This comprehensive acellular platform, capable of delivering recognition, co-stimulatory, and cytokine signals, represents a promising new technology for artificial antigen presentation.
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Rickert U, Welke J, Behrens D, Zavazava N. A divalent human leukocyte antigen-B7 fusion-protein up-regulates CD25 and CD69 in alloreactive CD8+ T cells bypassing CD28 costimulation. Transplantation 2006; 81:1337-44. [PMID: 16699464 DOI: 10.1097/01.tp.0000205770.07196.e6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
BACKGROUND T cells recognize major histocompatibility complex (MHC) molecules and their cryptic antigenic peptides on antigen-presenting cells and are generally triggered to proliferate, and when sufficient, co-stimulation is available. In soluble form, monomeric MHC molecules can induce apoptosis, anergy, or decreases of the T-cell receptor (TCR). METHODS A dimeric fusion protein of the human leukocyte antigens (HLA)-B7 was molecularly engineered and expressed in a B-cell line to allow secretion. Alloreactive T cells were generated according to the standard protocol. RESULTS A dimer of approximately 160 kD was obtained, affinity purified, and used to study T-cell interaction. In immobilized form, this protein efficiently stimulated alloreactive T cells to proliferate and produce interleukin (IL)-2 and interferon (IFN)-gamma in a concentration-dependent manner, up-regulating CD25 and CD69 expression. In contrast, the soluble fusion protein induced T-cell apoptosis. CONCLUSIONS The dichotomy in T-cell regulation by a divalent MHC fusion protein warrants the use of MHC multimers as custom-designed immune-regulatory molecules both in transplantation and autoimmune disease.
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Affiliation(s)
- Uta Rickert
- Institute of Anatomy, University of Kiel, Germany
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30
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Schamel WWA, Risueño RM, Minguet S, Ortíz AR, Alarcón B. A conformation- and avidity-based proofreading mechanism for the TCR–CD3 complex. Trends Immunol 2006; 27:176-82. [PMID: 16527543 DOI: 10.1016/j.it.2006.02.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2005] [Revised: 01/24/2006] [Accepted: 02/16/2006] [Indexed: 10/24/2022]
Abstract
During antigen recognition, T cells show high sensitivity and specificity, and a wide dynamic range. Paradoxically, these characteristics are based on low-affinity receptor-ligand interactions [between the T-cell antigen receptor (TCR-CD3) complex and the antigen peptide bound to MHC]. Recent evidence indicates that the TCR-CD3 is expressed as multivalent complexes in the membrane of non-stimulated T cells and that conformational changes in the TCR-CD3 can be induced by strong but not weak agonists. Here, we propose a thermodynamic model whereby the specificity of the TCR-CD3-pMHC interaction is explained by its multivalent nature. We also propose that the free energy barriers involved in the change in conformation of the receptor impose a response threshold and determine the kinetic properties of recognition. Finally, we suggest that multivalent TCR-CD3s can amplify signals by spreading them from pMHC-engaged TCR-CD3s to unengaged complexes as a consequence of the cooperativity in the system.
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Affiliation(s)
- Wolfgang W A Schamel
- Max Planck-Institut für Immunbiologie and University of Freiburg, Stübeweg 51, 79108 Freiburg, Germany
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31
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Stone JD, Stern LJ. CD8 T cells, like CD4 T cells, are triggered by multivalent engagement of TCRs by MHC-peptide ligands but not by monovalent engagement. THE JOURNAL OF IMMUNOLOGY 2006; 176:1498-505. [PMID: 16424178 DOI: 10.4049/jimmunol.176.3.1498] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
T cell activation is initiated by recognition of antigenic peptide presented in complex with MHC molecules on the surface of APCs. The mechanism by which this recognition occurs is still unclear, and many models exist in the literature. CD4 T cells have been shown to respond to soluble oligomers of activating class II MHC-peptide complexes, but not to soluble monomers. In determining the reactivity of CD8 T cells to soluble activating class I MHC-peptide complexes, a complicating phenomenon had been observed whereby peptide from soluble complexes was loaded onto cell surface MHCs on the T cells and re-presented to other T cells, clouding the true valency requirement for activation. This study uses soluble allogeneic class I MHC-peptide monomers and oligomers to stimulate murine CD8 T cells without the possible complication of peptide re-presentation. The results show that MHC class I monomers bind to, but do not activate, CD8 T cells whether the cells are in solution or adhered to a surface. Monomeric MHC class I binding can antagonize the stimulation triggered by soluble oligomers, a phenomenon also observed for CD4 T cells. Dimeric engagement is necessary and sufficient to stimulate downstream activation processes including TCR down-regulation, Zap70 phosphorylation, and CD25 and CD69 up-regulation, even in T cells that do not express the MHC coreceptor CD8. Thus, the valency dependence of the response of CD8 T cells to soluble MHC-peptide reagents is the same as previously observed for CD4 T cells.
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Affiliation(s)
- Jennifer D Stone
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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32
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Sigalov A, Aivazian D, Stern L. Homooligomerization of the cytoplasmic domain of the T cell receptor zeta chain and of other proteins containing the immunoreceptor tyrosine-based activation motif. Biochemistry 2004; 43:2049-61. [PMID: 14967045 DOI: 10.1021/bi035900h] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Antigen receptors on T cells, B cells, mast cells, and basophils all have cytoplasmic domains containing one or more copies of an immunoreceptor tyrosine-based activation motif (ITAM), tyrosine residues of which are phosphorylated upon receptor engagement in an early and obligatory event in the signaling cascade. How clustering of receptor extracellular domains leads to phosphorylation of cytoplasmic domain ITAMs is not known, and little structural or biochemical information is available for the ITAM-containing cytoplasmic domains. Here we investigate the conformation and oligomeric state of several immune receptor cytoplasmic domains, using purified recombinant proteins and a variety of biophysical and biochemical techniques. We show that all of the cytoplasmic domains of ITAM-containing signaling subunits studied are oligomeric in solution, namely, T cell antigen receptor zeta, CD3epsilon, CD3delta, and CD3gamma, B cell antigen receptor Igalpha and Igbeta, and Fc receptor FcepsilonRIgamma. For zeta(cyt), the oligomerization behavior is best described by a two-step monomer-dimer-tetramer fast dynamic equilibrium with dissociation constants in the order of approximately 10 microM (monomer-dimer) and approximately 1 mM (dimer-tetramer). In contrast to the other ITAM-containing proteins, Igalpha(cyt) forms stable dimers and tetramers even below 10 microM. Circular dichroic analysis reveals the lack of stable ordered structure of the cytoplasmic domains studied, and oligomerization does not change the random-coil-like conformation observed. The random-coil nature of zeta(cyt) was also confirmed by heteronuclear NMR. Phosphorylation of zeta(cyt) and FcepsilonRIgamma(cyt) does not significantly alter their oligomerization behavior. The implications of these results for transmembrane signaling and cellular activation by immune receptors are discussed.
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MESH Headings
- Amino Acid Motifs
- Chromatography, Gel
- Cross-Linking Reagents/chemistry
- Cytoplasm/chemistry
- Cytoplasm/metabolism
- Dimerization
- Escherichia coli/genetics
- Humans
- Light
- Lymphocyte Activation
- Membrane Proteins/biosynthesis
- Membrane Proteins/chemistry
- Membrane Proteins/genetics
- Membrane Proteins/isolation & purification
- Nuclear Magnetic Resonance, Biomolecular
- Phosphorylation
- Protein Structure, Secondary
- Protein Structure, Tertiary
- Receptors, Antigen, T-Cell/biosynthesis
- Receptors, Antigen, T-Cell/chemistry
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/isolation & purification
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/chemistry
- Recombinant Proteins/isolation & purification
- Recombinant Proteins/metabolism
- Scattering, Radiation
- Solutions
- Temperature
- Thermodynamics
- Tyrosine/chemistry
- Tyrosine/metabolism
- Ultracentrifugation
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Affiliation(s)
- Alexander Sigalov
- Department of Pathology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, Massachusetts 01655, USA.
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33
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Ye M, Kasey S, Khurana S, Nguyen NT, Schubert S, Nugent CT, Kuus-Reichel K, Hampl J. MHC class II tetramers containing influenza hemagglutinin and EBV EBNA1 epitopes detect reliably specific CD4+ T cells in healthy volunteers. Hum Immunol 2004; 65:507-13. [PMID: 15172451 DOI: 10.1016/j.humimm.2004.02.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2003] [Revised: 01/15/2004] [Accepted: 02/03/2004] [Indexed: 11/19/2022]
Abstract
Tracking antigen specific T cells with major histocompatibility complex (MHC) tetramers has provided us with insights into the dynamics of the adaptive immune system and holds great promise to aid in patient management and drug and vaccine development. Progress has been made primarily using MHC class I tetramers to monitor CD8(+) T cells, whereas corresponding efforts to stain CD4(+) T cells with class II tetramers have not been as successful. Two major reasons have been proposed for this lack of progress: (1). The frequency of antigen-specific CD4(+) T cells is lower than the frequency of CD8(+) T cells and (2). some, but not all, antigen- specific CD4(+) T cells can bind tetramer because of low functional avidity. In this study, we asked if CD4(+) T cells specific for common human viruses (e.g., influenza and Epstein-Barr) can be detected in healthy individuals previously exposed to them. We were able to clearly detect specific CD4(+) T cells in all donors after in vitro expansion of peripheral blood mononuclear cells. Furthermore, we observe a clear separation of tetramer negative and tetramer positive CD4(+) T cells in most samples similar to patterns commonly seen with class I tetramers. The data indicate that MHC class II tetramers can be used reliably for the identification of CD4(+) T cells specific for ubiquitous infectious agents in normal donors.
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Affiliation(s)
- Ming Ye
- Cell Analysis Development Center, Beckman Coulter, Inc, San Diego, CA 92121, USA
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Rokitskaya TI, Kotova EA, Antonenko YN. Tandem gramicidin channels cross-linked by streptavidin. J Gen Physiol 2003; 121:463-76. [PMID: 12719486 PMCID: PMC2217381 DOI: 10.1085/jgp.200208780] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2002] [Revised: 03/31/2003] [Accepted: 04/02/2003] [Indexed: 11/20/2022] Open
Abstract
The interaction of biotin-binding proteins with biotinylated gramicidin (gA5XB) was studied by monitoring single-channel activity and sensitized photoinactivation kinetics. It was discovered that the addition of streptavidin or avidin to the bathing solutions of a bilayer lipid membrane (BLM) with incorporated gA5XB induced the opening of a channel characterized by approximately doubled single-channel conductance and extremely long open-state duration. We believe that the deceleration of the photoinactivation kinetics observed here with streptavidin and previously (Rokitskaya, T.I., Y.N. Antonenko, E.A. Kotova, A. Anastasiadis, and F. Separovic. 2000. Biochemistry. 39:13053-13058) with avidin reflects the formation of long-lived channels of this type. Both opening and closing of the double-conductance channels occurred via a transient sub-state of the conductance coinciding with that of the usual single-channel transition. The appearance of the double-conductance channels after the addition of streptavidin was preceded by bursts of fast fluctuations of the current with the open state duration of the individual events of 60 ms. The streptavidin-induced double-conductance channels appeared to be inherent only to the gramicidin analogue with a biotin group linked to the COOH terminus through a long linker arm. Including biotinylated phosphatidylethanolamine into the BLM prevented the formation of the double-conductance channels even with the excess streptavidin. In view of the results obtained here, it is suggested that the double-conductance channel represents a tandem of two neighboring gA5XB channels with their COOH termini being cross-linked by the bound streptavidin at both sides of the BLM. The finding that streptavidin induces the formation of the tandem gramicidin channel comprising two channels functioning in concert is considered to be relevant to the physiologically important phenomenon of ligand-induced receptor oligomerization.
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35
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Mallet-Designe VI, Stratmann T, Homann D, Carbone F, Oldstone MBA, Teyton L. Detection of low-avidity CD4+ T cells using recombinant artificial APC: following the antiovalbumin immune response. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:123-31. [PMID: 12496391 DOI: 10.4049/jimmunol.170.1.123] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Subtle differences oppose CD4+ to CD8+ T cell physiologies that lead to different arrays of effector functions. Interestingly, this dichotomy has also unexpected practical consequences such as the inefficacy of many MHC class II tetramers in detecting specific CD4+ T cells. As a mean to study the CD4+ anti-OVA response in H-2(d) and H-2(b) genetic backgrounds, we developed I-A(d)- and I-A(b)-OVA recombinant MHC monomers and tetramers. We were able to show that in this particular system, despite normal biological activity, MHC class II tetramers failed to stain specific T cells. This failure was shown to be associated with a lack of cooperation between binding sites within the tetramer as measured by surface plasmon resonance. This limited cooperativeness translated into a low "functional avidity" and very transient binding of the tetramers to T cells. To overcome this biophysical barrier, recombinant artificial APC that display MHC molecules in a lipid bilayer were developed. The plasticity and size of the MHC-bearing fluorescent liposomes allowed binding to Ag-specific T cells and the detection of low numbers of anti-OVA T cells following immunization. The same liposomes were able, at 37 degrees C, to induce the full reorganization of the T cell signaling molecules and the formation of an immunological synapse. Artificial APC will allow T cell detection and the dissection of the molecular events of T cell activation and will help us understand the fundamental differences between CD4+ and CD8+ T cells.
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36
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Pelegrí C, Vilaplana J, Castellote C, Rabanal M, Franch A, Castell M. Circadian rhythms in surface molecules of rat blood lymphocytes. Am J Physiol Cell Physiol 2003; 284:C67-76. [PMID: 12388092 DOI: 10.1152/ajpcell.00084.2002] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present article examines whether the expression of certain surface molecules that trigger immune responses shows a circadian rhythm. We also analyzed the rhythms in the number and percentage of lymphocyte subpopulations, in the leukocyte differential counts, and in the total red and white blood cell counts. Blood samples obtained from rats at 2-h intervals for 24 h were stained with several mouse monoclonal antibodies directed against lymphocyte surface molecules and processed by flow cytometry. The number of B, total T, Tgammadelta, Th, and Ts/c cells followed a 24-h rhythm with a peak in the first half of the resting period. The expression of CD45, CD5, CD3, and CD4 followed a circadian rhythm. Their acrophases suggested temporal association between CD45 and CD5 at the end of the active phase and between CD4 and CD3 at the beginning of this phase. This temporal organization could have an important role for immune cell function.
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Affiliation(s)
- Carme Pelegrí
- Grup d'Autoimmunitat i Tolerància, Departament de Fisiologia-Divisió IV, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain.
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37
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Affiliation(s)
- Charles J Hackett
- Division of Allergy, Immunology and Transplantation,National Institute ofAllergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20817, USA.
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38
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Jain S. Artificial in vivo antigen presentation by the APCs and subsequent T-cell activation: a feasibility analysis. FEBS Lett 2002; 515:146-50. [PMID: 11943211 DOI: 10.1016/s0014-5793(02)02458-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Inappropriate antigen presentation by the antigen-presenting cells (APCs) is a cause of various diseases. One of the ways to combat these diseases is to immobilize the APCs near the infected tissue or a tissue which is susceptible to an antigen. The antigen is presented by the APCs present in the immobilized form on an implant and these upon binding to T(H)-cells result in triggering of a cascade of events as part of the natural immune response leading to the destruction of the antigen. This system has been modeled as a dialysis bag containing immobilized receptors inside the bag and the ligand diffusing out of the bag. The simulations show that by using the implant, the concentration of the ligand that has diffused into the tissue matrix can be substantially reduced and by suitably choosing the coupler size, the T(H)-cells can also effectively be activated.
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Affiliation(s)
- Siddhartha Jain
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Hauz Khas, 110 016, New Delhi, India.
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