1
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Rosenberg AM, Ayres CM, Medina-Cucurella AV, Whitehead TA, Baker BM. Enhanced T cell receptor specificity through framework engineering. Front Immunol 2024; 15:1345368. [PMID: 38545094 PMCID: PMC10967027 DOI: 10.3389/fimmu.2024.1345368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 02/15/2024] [Indexed: 04/12/2024] Open
Abstract
Development of T cell receptors (TCRs) as immunotherapeutics is hindered by inherent TCR cross-reactivity. Engineering more specific TCRs has proven challenging, as unlike antibodies, improving TCR affinity does not usually improve specificity. Although various protein design approaches have been explored to surmount this, mutations in TCR binding interfaces risk broadening specificity or introducing new reactivities. Here we explored if TCR specificity could alternatively be tuned through framework mutations distant from the interface. Studying the 868 TCR specific for the HIV SL9 epitope presented by HLA-A2, we used deep mutational scanning to identify a framework mutation above the mobile CDR3β loop. This glycine to proline mutation had no discernable impact on binding affinity or functional avidity towards the SL9 epitope but weakened recognition of SL9 escape variants and led to fewer responses in a SL9-derived positional scanning library. In contrast, an interfacial mutation near the tip of CDR3α that also did not impact affinity or functional avidity towards SL9 weakened specificity. Simulations indicated that the specificity-enhancing mutation functions by reducing the range of loop motions, limiting the ability of the TCR to adjust to different ligands. Although our results are likely to be TCR dependent, using framework engineering to control TCR loop motions may be a viable strategy for improving the specificity of TCR-based immunotherapies.
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Affiliation(s)
- Aaron M. Rosenberg
- Department of Chemistry and Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN, United States
| | - Cory M. Ayres
- Department of Chemistry and Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN, United States
| | | | - Timothy A. Whitehead
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, United States
| | - Brian M. Baker
- Department of Chemistry and Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN, United States
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2
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Koyama K, Hashimoto K, Nagao C, Mizuguchi K. Attention network for predicting T-cell receptor-peptide binding can associate attention with interpretable protein structural properties. FRONTIERS IN BIOINFORMATICS 2023; 3:1274599. [PMID: 38170146 PMCID: PMC10759225 DOI: 10.3389/fbinf.2023.1274599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 11/27/2023] [Indexed: 01/05/2024] Open
Abstract
Understanding how a T-cell receptor (TCR) recognizes its specific ligand peptide is crucial for gaining an insight into biological functions and disease mechanisms. Despite its importance, experimentally determining TCR-peptide-major histocompatibility complex (TCR-pMHC) interactions is expensive and time-consuming. To address this challenge, computational methods have been proposed, but they are typically evaluated by internal retrospective validation only, and few researchers have incorporated and tested an attention layer from language models into structural information. Therefore, in this study, we developed a machine learning model based on a modified version of Transformer, a source-target attention neural network, to predict the TCR-pMHC interaction solely from the amino acid sequences of the TCR complementarity-determining region (CDR) 3 and the peptide. This model achieved competitive performance on a benchmark dataset of the TCR-pMHC interaction, as well as on a truly new external dataset. Additionally, by analyzing the results of binding predictions, we associated the neural network weights with protein structural properties. By classifying the residues into large- and small-attention groups, we identified statistically significant properties associated with the largely attended residues such as hydrogen bonds within CDR3. The dataset that we created and the ability of our model to provide an interpretable prediction of TCR-peptide binding should increase our knowledge about molecular recognition and pave the way for designing new therapeutics.
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Affiliation(s)
- Kyohei Koyama
- Laboratory for Computational Biology, Institute for Protein Research, Osaka University, Osaka, Japan
- National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Kosuke Hashimoto
- Laboratory for Computational Biology, Institute for Protein Research, Osaka University, Osaka, Japan
| | - Chioko Nagao
- Laboratory for Computational Biology, Institute for Protein Research, Osaka University, Osaka, Japan
| | - Kenji Mizuguchi
- Laboratory for Computational Biology, Institute for Protein Research, Osaka University, Osaka, Japan
- National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
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3
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Mo G, Lu X, Wu S, Zhu W. Strategies and rules for tuning TCR-derived therapy. Expert Rev Mol Med 2023; 26:e4. [PMID: 38095091 PMCID: PMC11062142 DOI: 10.1017/erm.2023.27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 08/17/2023] [Accepted: 12/05/2023] [Indexed: 04/04/2024]
Abstract
Manipulation of T cells has revolutionized cancer immunotherapy. Notably, the use of T cells carrying engineered T cell receptors (TCR-T) offers a favourable therapeutic pathway, particularly in the treatment of solid tumours. However, major challenges such as limited clinical response efficacy, off-target effects and tumour immunosuppressive microenvironment have hindered the clinical translation of this approach. In this review, we mainly want to guide TCR-T investigators on several major issues they face in the treatment of solid tumours after obtaining specific TCR sequences: (1) whether we have to undergo affinity maturation or not, and what parameter we should use as a criterion for being more effective. (2) What modifications can be added to counteract the tumour inhibitory microenvironment to make our specific T cells to be more effective and what is the safety profile of such modifications? (3) What are the new forms and possibilities for TCR-T cell therapy in the future?
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Affiliation(s)
- Guoheng Mo
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xinyu Lu
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Sha Wu
- Department of Immunology/Guangdong Provincial Key Laboratory of Proteomics, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Wei Zhu
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
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4
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Peng X, Lei Y, Feng P, Jia L, Ma J, Zhao D, Zeng J. Characterizing the interaction conformation between T-cell receptors and epitopes with deep learning. NAT MACH INTELL 2023. [DOI: 10.1038/s42256-023-00634-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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5
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Crean RM, Pudney CR, Cole DK, van der Kamp MW. Reliable In Silico Ranking of Engineered Therapeutic TCR Binding Affinities with MMPB/GBSA. J Chem Inf Model 2022; 62:577-590. [PMID: 35049312 PMCID: PMC9097153 DOI: 10.1021/acs.jcim.1c00765] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
![]()
Accurate
and efficient in silico ranking of protein–protein
binding affinities is useful for protein design with applications
in biological therapeutics. One popular approach to rank binding affinities
is to apply the molecular mechanics Poisson–Boltzmann/generalized
Born surface area (MMPB/GBSA) method to molecular dynamics (MD) trajectories.
Here, we identify protocols that enable the reliable evaluation of
T-cell receptor (TCR) variants binding to their target, peptide-human
leukocyte antigens (pHLAs). We suggest different protocols for variant
sets with a few (≤4) or many mutations, with entropy corrections
important for the latter. We demonstrate how potential outliers could
be identified in advance and that just 5–10 replicas of short
(4 ns) MD simulations may be sufficient for the reproducible and accurate
ranking of TCR variants. The protocols developed here can be applied
toward in silico screening during the optimization
of therapeutic TCRs, potentially reducing both the cost and time taken
for biologic development.
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Affiliation(s)
| | | | - David K. Cole
- Immunocore Ltd., Milton Park, Abingdon OX14 4RY, U.K
- Division of Infection & Immunity, Cardiff University, Cardiff CF14 4XN, U.K
| | - Marc W. van der Kamp
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, Bristol BS8 1TD, U.K
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6
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Holland CJ, Crean RM, Pentier JM, de Wet B, Lloyd A, Srikannathasan V, Lissin N, Lloyd KA, Blicher TH, Conroy PJ, Hock M, Pengelly RJ, Spinner TE, Cameron B, Potter EA, Jeyanthan A, Molloy PE, Sami M, Aleksic M, Liddy N, Robinson RA, Harper S, Lepore M, Pudney CR, van der Kamp MW, Rizkallah PJ, Jakobsen BK, Vuidepot A, Cole DK. Specificity of bispecific T cell receptors and antibodies targeting peptide-HLA. J Clin Invest 2021; 130:2673-2688. [PMID: 32310221 DOI: 10.1172/jci130562] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 02/11/2020] [Indexed: 01/09/2023] Open
Abstract
Tumor-associated peptide-human leukocyte antigen complexes (pHLAs) represent the largest pool of cell surface-expressed cancer-specific epitopes, making them attractive targets for cancer therapies. Soluble bispecific molecules that incorporate an anti-CD3 effector function are being developed to redirect T cells against these targets using 2 different approaches. The first achieves pHLA recognition via affinity-enhanced versions of natural TCRs (e.g., immune-mobilizing monoclonal T cell receptors against cancer [ImmTAC] molecules), whereas the second harnesses an antibody-based format (TCR-mimic antibodies). For both classes of reagent, target specificity is vital, considering the vast universe of potential pHLA molecules that can be presented on healthy cells. Here, we made use of structural, biochemical, and computational approaches to investigate the molecular rules underpinning the reactivity patterns of pHLA-targeting bispecifics. We demonstrate that affinity-enhanced TCRs engage pHLA using a comparatively broad and balanced energetic footprint, with interactions distributed over several HLA and peptide side chains. As ImmTAC molecules, these TCRs also retained a greater degree of pHLA selectivity, with less off-target activity in cellular assays. Conversely, TCR-mimic antibodies tended to exhibit binding modes focused more toward hot spots on the HLA surface and exhibited a greater degree of crossreactivity. Our findings extend our understanding of the basic principles that underpin pHLA selectivity and exemplify a number of molecular approaches that can be used to probe the specificity of pHLA-targeting molecules, aiding the development of future reagents.
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Affiliation(s)
| | - Rory M Crean
- Department of Biology and Biochemistry and.,Doctoral Training Centre in Sustainable Chemical Technologies, University of Bath, Bath, United Kingdom
| | | | - Ben de Wet
- Immunocore Ltd., Milton Park, Abingdon, United Kingdom
| | | | | | | | - Katy A Lloyd
- Immunocore Ltd., Milton Park, Abingdon, United Kingdom
| | | | - Paul J Conroy
- Immunocore Ltd., Milton Park, Abingdon, United Kingdom
| | - Miriam Hock
- Immunocore Ltd., Milton Park, Abingdon, United Kingdom
| | | | | | - Brian Cameron
- Immunocore Ltd., Milton Park, Abingdon, United Kingdom
| | | | | | | | - Malkit Sami
- Immunocore Ltd., Milton Park, Abingdon, United Kingdom
| | - Milos Aleksic
- Immunocore Ltd., Milton Park, Abingdon, United Kingdom
| | | | | | | | - Marco Lepore
- Immunocore Ltd., Milton Park, Abingdon, United Kingdom
| | | | | | - Pierre J Rizkallah
- Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom
| | | | | | - David K Cole
- Immunocore Ltd., Milton Park, Abingdon, United Kingdom.,Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom
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7
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Gene Augmentation and Editing to Improve TCR Engineered T Cell Therapy against Solid Tumors. Vaccines (Basel) 2020; 8:vaccines8040733. [PMID: 33287413 PMCID: PMC7761868 DOI: 10.3390/vaccines8040733] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 11/23/2020] [Accepted: 12/01/2020] [Indexed: 12/27/2022] Open
Abstract
Recent developments in gene engineering technologies have drastically improved the therapeutic treatment options for cancer patients. The use of effective chimeric antigen receptor T (CAR-T) cells and recombinant T cell receptor engineered T (rTCR-T) cells has entered the clinic for treatment of hematological malignancies with promising results. However, further fine-tuning, to improve functionality and safety, is necessary to apply these strategies for the treatment of solid tumors. The immunosuppressive microenvironment, the surrounding stroma, and the tumor heterogeneity often results in poor T cell reactivity, functionality, and a diminished infiltration rates, hampering the efficacy of the treatment. The focus of this review is on recent advances in rTCR-T cell therapy, to improve both functionality and safety, for potential treatment of solid tumors and provides an overview of ongoing clinical trials. Besides selection of the appropriate tumor associated antigen, efficient delivery of an optimized recombinant TCR transgene into the T cells, in combination with gene editing techniques eliminating the endogenous TCR expression and disrupting specific inhibitory pathways could improve adoptively transferred T cells. Armoring the rTCR-T cells with specific cytokines and/or chemokines and their receptors, or targeting the tumor stroma, can increase the infiltration rate of the immune cells within the solid tumors. On the other hand, clinical “off-tumor/on-target” toxicities are still a major potential risk and can lead to severe adverse events. Incorporation of safety switches in rTCR-T cells can guarantee additional safety. Recent clinical trials provide encouraging data and emphasize the relevance of gene therapy and gene editing tools for potential treatment of solid tumors.
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8
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Singh NK, Alonso JA, Harris DT, Anderson SD, Ma J, Hellman LM, Rosenberg AM, Kolawole EM, Evavold BD, Kranz DM, Baker BM. An Engineered T Cell Receptor Variant Realizes the Limits of Functional Binding Modes. Biochemistry 2020; 59:4163-4175. [PMID: 33074657 DOI: 10.1021/acs.biochem.0c00689] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
T cell receptors (TCRs) orchestrate cellular immunity by recognizing peptides presented by a range of major histocompatibility complex (MHC) proteins. Naturally occurring TCRs bind the composite peptide/MHC surface, recognizing peptides that are structurally and chemically compatible with the TCR binding site. Here we describe a molecularly evolved TCR variant that binds the human class I MHC protein HLA-A2 independent of the bound peptide, achieved by a drastic perturbation of the TCR binding geometry that places the molecule far from the peptide binding groove. This unique geometry is unsupportive of normal T cell signaling. A substantial divergence between affinity measurements in solution and in two dimensions between proximal cell membranes leads us to attribute the lack of signaling to steric hindrance that limits binding in the confines of a cell-cell interface. Our results provide an example of how receptor binding geometry can impact T cell function and provide further support for the view that germline-encoded residues in TCR binding loops evolved to drive productive TCR recognition and signaling.
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Affiliation(s)
- Nishant K Singh
- Department of Chemistry and Biochemistry and Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Jesus A Alonso
- Department of Chemistry and Biochemistry and Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Daniel T Harris
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, Illinois 61801, United States
| | - Scott D Anderson
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, Illinois 61801, United States
| | - Jiaqi Ma
- Department of Chemistry and Biochemistry and Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Lance M Hellman
- Department of Chemistry and Biochemistry and Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Aaron M Rosenberg
- Department of Chemistry and Biochemistry and Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Elizabeth M Kolawole
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, Utah 84112, United States
| | - Brian D Evavold
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, Utah 84112, United States
| | - David M Kranz
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, Illinois 61801, United States
| | - Brian M Baker
- Department of Chemistry and Biochemistry and Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana 46556, United States
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9
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Crean RM, MacLachlan BJ, Madura F, Whalley T, Rizkallah PJ, Holland CJ, McMurran C, Harper S, Godkin A, Sewell AK, Pudney CR, van der Kamp MW, Cole DK. Molecular Rules Underpinning Enhanced Affinity Binding of Human T Cell Receptors Engineered for Immunotherapy. Mol Ther Oncolytics 2020; 18:443-456. [PMID: 32913893 PMCID: PMC7452143 DOI: 10.1016/j.omto.2020.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 07/27/2020] [Indexed: 10/25/2022] Open
Abstract
Immuno-oncology approaches that utilize T cell receptors (TCRs) are becoming highly attractive because of their potential to target virtually all cellular proteins, including cancer-specific epitopes, via the recognition of peptide-human leukocyte antigen (pHLA) complexes presented at the cell surface. However, because natural TCRs generally recognize cancer-derived pHLAs with very weak affinities, efforts have been made to enhance their binding strength, in some cases by several million-fold. In this study, we investigated the mechanisms underpinning human TCR affinity enhancement by comparing the crystal structures of engineered enhanced affinity TCRs with those of their wild-type progenitors. Additionally, we performed molecular dynamics simulations to better understand the energetic mechanisms driving the affinity enhancements. These data demonstrate that supra-physiological binding affinities can be achieved without altering native TCR-pHLA binding modes via relatively subtle modifications to the interface contacts, often driven through the addition of buried hydrophobic residues. Individual energetic components of the TCR-pHLA interaction governing affinity enhancements were distinct and highly variable for each TCR, often resulting from additive, or knock-on, effects beyond the mutated residues. This comprehensive analysis of affinity-enhanced TCRs has important implications for the future rational design of engineered TCRs as efficacious and safe drugs for cancer treatment.
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Affiliation(s)
- Rory M. Crean
- Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, UK
- Doctoral Training Centre in Sustainable Chemical Technologies, University of Bath, Bath, BA2 7AY, UK
| | | | - Florian Madura
- Division of Infection & Immunity, Cardiff University, Cardiff, CF14 4XN, UK
| | - Thomas Whalley
- Division of Infection & Immunity, Cardiff University, Cardiff, CF14 4XN, UK
| | | | | | | | | | - Andrew Godkin
- Division of Infection & Immunity, Cardiff University, Cardiff, CF14 4XN, UK
| | - Andrew K. Sewell
- Division of Infection & Immunity, Cardiff University, Cardiff, CF14 4XN, UK
| | - Christopher R. Pudney
- Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, UK
- Centre for Therapeutic Innovation, University of Bath, Bath, BA2 7AY, UK
| | - Marc W. van der Kamp
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - David K. Cole
- Division of Infection & Immunity, Cardiff University, Cardiff, CF14 4XN, UK
- Immunocore, Ltd., Abingdon, OX14 4RY, UK
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10
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The Quest for the Best: How TCR Affinity, Avidity, and Functional Avidity Affect TCR-Engineered T-Cell Antitumor Responses. Cells 2020; 9:cells9071720. [PMID: 32708366 PMCID: PMC7408146 DOI: 10.3390/cells9071720] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/13/2020] [Accepted: 07/15/2020] [Indexed: 12/11/2022] Open
Abstract
Over the past decades, adoptive transfer of T cells has revolutionized cancer immunotherapy. In particular, T-cell receptor (TCR) engineering of T cells has marked important milestones in developing more precise and personalized cancer immunotherapies. However, to get the most benefit out of this approach, understanding the role that TCR affinity, avidity, and functional avidity play on how TCRs and T cells function in the context of tumor-associated antigen (TAA) recognition is vital to keep generating improved adoptive T-cell therapies. Aside from TCR-related parameters, other critical factors that govern T-cell activation are the effect of TCR co-receptors on TCR–peptide-major histocompatibility complex (pMHC) stabilization and TCR signaling, tumor epitope density, and TCR expression levels in TCR-engineered T cells. In this review, we describe the key aspects governing TCR specificity, T-cell activation, and how these concepts can be applied to cancer-specific TCR redirection of T cells.
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11
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Coles CH, McMurran C, Lloyd A, Hock M, Hibbert L, Raman MCC, Hayes C, Lupardus P, Cole DK, Harper S. T cell receptor interactions with human leukocyte antigen govern indirect peptide selectivity for the cancer testis antigen MAGE-A4. J Biol Chem 2020; 295:11486-11494. [PMID: 32532817 PMCID: PMC7450119 DOI: 10.1074/jbc.ra120.014016] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/11/2020] [Indexed: 12/18/2022] Open
Abstract
T cell-mediated immunity is governed primarily by T cell receptor (TCR) recognition of peptide-human leukocyte antigen (pHLA) complexes and is essential for immunosurveillance and disease control. This interaction is generally stabilized by interactions between the HLA surface and TCR germline-encoded complementarity-determining region (CDR) loops 1 and 2, whereas peptide selectivity is guided by direct interactions with the TCR CDR3 loops. Here, we solved the structure of a newly identified TCR in complex with a clinically relevant peptide derived from the cancer testis antigen melanoma antigen-A4 (MAGE-A4). The TCR bound pHLA in a position shifted toward the peptide's N terminus. This enabled the TCR to achieve peptide selectivity via an indirect mechanism, whereby the TCR sensed the first residue of the peptide through HLA residue Trp-167, which acted as a tunable gateway. Amino acid substitutions at peptide position 1 predicted to alter the HLA Trp-167 side-chain conformation abrogated TCR binding, indicating that this indirect binding mechanism is essential for peptide recognition. These findings extend our understanding of the molecular rules that underpin antigen recognition by TCRs and have important implications for the development of TCR-based therapies.
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Affiliation(s)
| | | | | | | | | | | | | | | | - David K Cole
- Immunocore Ltd., Abingdon, United Kingdom .,Cardiff University School of Medicine, Cardiff, United Kingdom
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12
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Sádio F, Stadlmayr G, Stadlbauer K, Gräf M, Scharrer A, Rüker F, Wozniak-Knopp G. Stabilization of soluble high-affinity T-cell receptor with de novo disulfide bonds. FEBS Lett 2019; 594:477-490. [PMID: 31552676 PMCID: PMC7027902 DOI: 10.1002/1873-3468.13616] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 09/04/2019] [Accepted: 09/17/2019] [Indexed: 12/12/2022]
Abstract
Soluble T‐cell receptors (TCRs) have recently gained visibility as target‐recognition units of anticancer immunotherapeutic agents. Here, we improved the thermal stability of the well‐expressed high‐affinity A6 TCR by introducing pairs of cysteines in the invariable parts of the α‐ and β‐chain. A mutant with a novel intradomain disulfide bond in each chain also tested superior to the wild‐type in the accelerated stability assay. Binding of the mutant to the soluble cognate peptide (cp)–MHC and to the peptide‐loaded T2 cell line was equal to the wild‐type A6 TCR. The same stabilization motif worked efficiently in TCRs with different specificities, such as DMF5 and 1G4. Altogether, the biophysical properties of the soluble TCR molecule could be improved, without affecting its expression level and antigen‐binding specificity.
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Affiliation(s)
- Flávio Sádio
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Gerhard Stadlmayr
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Katharina Stadlbauer
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Maximilian Gräf
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Agnes Scharrer
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Florian Rüker
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Gordana Wozniak-Knopp
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
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13
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Madura F, Rizkallah PJ, Legut M, Holland CJ, Fuller A, Bulek A, Schauenburg AJ, Trimby A, Hopkins JR, Wells SA, Godkin A, Miles JJ, Sami M, Li Y, Liddy N, Jakobsen BK, Loveridge EJ, Cole DK, Sewell AK. TCR-induced alteration of primary MHC peptide anchor residue. Eur J Immunol 2019; 49:1052-1066. [PMID: 31091334 PMCID: PMC6618058 DOI: 10.1002/eji.201948085] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 03/21/2019] [Accepted: 05/14/2019] [Indexed: 12/12/2022]
Abstract
The HLA-A*02:01-restricted decapeptide EAAGIGILTV, derived from melanoma antigen recognized by T-cells-1 (MART-1) protein, represents one of the best-studied tumor associated T-cell epitopes, but clinical results targeting this peptide have been disappointing. This limitation may reflect the dominance of the nonapeptide, AAGIGILTV, at the melanoma cell surface. The decapeptide and nonapeptide are presented in distinct conformations by HLA-A*02:01 and TCRs from clinically relevant T-cell clones recognize the nonapeptide poorly. Here, we studied the MEL5 TCR that potently recognizes the nonapeptide. The structure of the MEL5-HLA-A*02:01-AAGIGILTV complex revealed an induced fit mechanism of antigen recognition involving altered peptide-MHC anchoring. This "flexing" at the TCR-peptide-MHC interface to accommodate the peptide antigen explains previously observed incongruences in this well-studied system and has important implications for future therapeutic approaches. Finally, this study expands upon the mechanisms by which molecular plasticity can influence antigen recognition by T cells.
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Affiliation(s)
| | | | | | | | - Anna Fuller
- School of MedicineCardiff UniversityCardiffUK
| | - Anna Bulek
- School of MedicineCardiff UniversityCardiffUK
| | | | | | | | | | | | - John J. Miles
- School of MedicineCardiff UniversityCardiffUK
- Centre for Biodiscovery and Molecular Development of TherapeuticsAustralian Institute of Tropical Health and MedicineJames Cook UniversityCairnsQueenslandAustralia
| | | | - Yi Li
- Immunocore Ltd.AbingdonUK
| | | | | | - E. Joel Loveridge
- School of ChemistryCardiff UniversityCardiffUK
- Department of ChemistrySwansea UniversitySwanseaUK
| | - David K. Cole
- School of MedicineCardiff UniversityCardiffUK
- Immunocore Ltd.AbingdonUK
| | - Andrew K. Sewell
- School of MedicineCardiff UniversityCardiffUK
- Systems Immunity Research InstituteCardiff UniversityCardiffUK
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14
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Salutari I, Martin R, Caflisch A. The 3A6-TCR/superagonist/HLA-DR2a complex shows similar interface and reduced flexibility compared to the complex with self-peptide. Proteins 2019; 88:31-46. [PMID: 31237711 DOI: 10.1002/prot.25764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 06/10/2019] [Accepted: 06/15/2019] [Indexed: 11/11/2022]
Abstract
T-cell receptor (TCR) recognition of the myelin basic protein (MBP) peptide presented by major histocompatibility complex (MHC) protein HLA-DR2a, one of the MHC class II alleles associated with multiple sclerosis, is highly variable. Interactions in the trimolecular complex between the TCR of the MBP83-99-specific T cell clone 3A6 with the MBP-peptide/HLA-DR2a (abbreviated TCR/pMHC) lead to substantially different proliferative responses when comparing the wild-type decapeptide MBP90-99 and a superagonist peptide, which differs mainly in the residues that point toward the TCR. Here, we investigate the influence of the peptide sequence on the interface and intrinsic plasticity of the TCR/pMHC trimolecular and pMHC bimolecular complexes by molecular dynamics simulations. The intermolecular contacts at the TCR/pMHC interface are similar for the complexes with the superagonist and the MBP self-peptide. The orientation angle between TCR and pMHC fluctuates less in the complex with the superagonist peptide. Thus, the higher structural stability of the TCR/pMHC tripartite complex with the superagonist peptide, rather than a major difference in binding mode with respect to the self-peptide, seems to be responsible for the stronger proliferative response.
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Affiliation(s)
- Ilaria Salutari
- Department of Biochemistry, University of Zürich, Zürich, Switzerland
| | - Roland Martin
- Department of Neurology, University Hospital Zürich, Zürich, Switzerland
| | - Amedeo Caflisch
- Department of Biochemistry, University of Zürich, Zürich, Switzerland
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15
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Wagner EK, Qerqez AN, Stevens CA, Nguyen AW, Delidakis G, Maynard JA. Human cytomegalovirus-specific T-cell receptor engineered for high affinity and soluble expression using mammalian cell display. J Biol Chem 2019; 294:5790-5804. [PMID: 30796163 PMCID: PMC6463697 DOI: 10.1074/jbc.ra118.007187] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 02/07/2019] [Indexed: 01/01/2023] Open
Abstract
T-cell receptors (TCR) have considerable potential as therapeutics and antibody-like reagents to monitor disease progression and vaccine efficacy. Whereas antibodies recognize only secreted and surface-bound proteins, TCRs recognize otherwise inaccessible disease-associated intracellular proteins when they are presented as processed peptides bound to major histocompatibility complexes (pMHC). TCRs have been primarily explored for cancer therapy applications but could also target infectious diseases such as cytomegalovirus (CMV). However, TCRs are more difficult to express and engineer than antibodies, and advanced methods are needed to enable their widespread use. Here, we engineered the human CMV-specific TCR RA14 for high-affinity and robust soluble expression. To achieve this, we adapted our previously reported mammalian display system to present TCR extracellular domains and used this to screen CDR3 libraries for clones with increased pMHC affinity. After three rounds of selection, characterized clones retained peptide specificity and activation when expressed on the surface of human Jurkat T cells. We obtained high yields of soluble, monomeric protein by fusing the TCR extracellular domains to antibody hinge and Fc constant regions, adding a stabilizing disulfide bond between the constant domains and disrupting predicted glycosylation sites. One variant exhibited 50 nm affinity for its cognate pMHC, as measured by surface plasmon resonance, and specifically stained cells presenting this pMHC. Our work has identified a human TCR with high affinity for the immunodominant CMV peptide and offers a new strategy to rapidly engineer soluble TCRs for biomedical applications.
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Affiliation(s)
- Ellen K Wagner
- From the McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712
| | - Ahlam N Qerqez
- From the McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712
| | - Christopher A Stevens
- From the McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712
| | - Annalee W Nguyen
- From the McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712
| | - George Delidakis
- From the McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712
| | - Jennifer A Maynard
- From the McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712.
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16
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MacLachlan BJ, Greenshields-Watson A, Mason GH, Schauenburg AJ, Bianchi V, Rizkallah PJ, Sewell AK, Fuller A, Cole DK. Using X-ray Crystallography, Biophysics, and Functional Assays to Determine the Mechanisms Governing T-cell Receptor Recognition of Cancer Antigens. J Vis Exp 2017:54991. [PMID: 28287509 PMCID: PMC5408581 DOI: 10.3791/54991] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Human CD8+ cytotoxic T lymphocytes (CTLs) are known to play an important role in tumor control. In order to carry out this function, the cell surface-expressed T-cell receptor (TCR) must functionally recognize human leukocyte antigen (HLA)-restricted tumor-derived peptides (pHLA). However, we and others have shown that most TCRs bind sub-optimally to tumor antigens. Uncovering the molecular mechanisms that define this poor recognition could aid in the development of new targeted therapies that circumnavigate these shortcomings. Indeed, present therapies that lack this molecular understanding have not been universally effective. Here, we describe methods that we commonly employ in the laboratory to determine how the nature of the interaction between TCRs and pHLA governs T-cell functionality. These methods include the generation of soluble TCRs and pHLA and the use of these reagents for X-ray crystallography, biophysical analysis, and antigen-specific T-cell staining with pHLA multimers. Using these approaches and guided by structural analysis, it is possible to modify the interaction between TCRs and pHLA and to then test how these modifications impact T-cell antigen recognition. These findings have already helped to clarify the mechanism of T-cell recognition of a number of cancer antigens and could direct the development of altered peptides and modified TCRs for new cancer therapies.
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Affiliation(s)
- Bruce J MacLachlan
- Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University
| | | | - Georgina H Mason
- Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University
| | - Andrea J Schauenburg
- Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University
| | - Valentina Bianchi
- Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University; Department of Oncology, University Hospital of Lausanne (CHUV); Ludwig Insitutue for Cancer Research, Lausanne Branch, University of Lausanne
| | - Pierre J Rizkallah
- Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University
| | - Andrew K Sewell
- Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University
| | - Anna Fuller
- Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University
| | - David K Cole
- Division of Infection and Immunity and Systems Immunity Research Institute, Cardiff University;
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17
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Blevins SJ, Baker BM. Using Global Analysis to Extend the Accuracy and Precision of Binding Measurements with T cell Receptors and Their Peptide/MHC Ligands. Front Mol Biosci 2017; 4:2. [PMID: 28197404 PMCID: PMC5281623 DOI: 10.3389/fmolb.2017.00002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 01/11/2017] [Indexed: 11/13/2022] Open
Abstract
In cellular immunity, clonally distributed T cell receptors (TCRs) engage complexes of peptides bound to major histocompatibility complex proteins (pMHCs). In the interactions of TCRs with pMHCs, regions of restricted and variable diversity align in a structurally complex fashion. Many studies have used mutagenesis to attempt to understand the "roles" played by various interface components in determining TCR recognition properties such as specificity and cross-reactivity. However, these measurements are often complicated or even compromised by the weak affinities TCRs maintain toward pMHC. Here, we demonstrate how global analysis of multiple datasets can be used to significantly extend the accuracy and precision of such TCR binding experiments. Application of this approach should positively impact efforts to understand TCR recognition and facilitate the creation of mutational databases to help engineer TCRs with tuned molecular recognition properties. We also show how global analysis can be used to analyze double mutant cycles in TCR-pMHC interfaces, which can lead to new insights into immune recognition.
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Affiliation(s)
- Sydney J Blevins
- Department of Chemistry and Biochemistry and the Harper Cancer Research Institute, University of Notre Dame Notre Dame, IN, USA
| | - Brian M Baker
- Department of Chemistry and Biochemistry and the Harper Cancer Research Institute, University of Notre Dame Notre Dame, IN, USA
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18
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An Engineered Switch in T Cell Receptor Specificity Leads to an Unusual but Functional Binding Geometry. Structure 2016; 24:1142-1154. [PMID: 27238970 DOI: 10.1016/j.str.2016.04.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 03/31/2016] [Accepted: 04/19/2016] [Indexed: 11/21/2022]
Abstract
Utilizing a diverse binding site, T cell receptors (TCRs) specifically recognize a composite ligand comprised of a foreign peptide and a major histocompatibility complex protein (MHC). To help understand the determinants of TCR specificity, we studied a parental and engineered receptor whose peptide specificity had been switched via molecular evolution. Altered specificity was associated with a significant change in TCR-binding geometry, but this did not impact the ability of the TCR to signal in an antigen-specific manner. The determinants of binding and specificity were distributed among contact and non-contact residues in germline and hypervariable loops, and included disruption of key TCR-MHC interactions that bias αβ TCRs toward particular binding modes. Sequence-fitness landscapes identified additional mutations that further enhanced specificity. Our results demonstrate that TCR specificity arises from the distributed action of numerous sites throughout the interface, with significant implications for engineering therapeutic TCRs with novel and functional recognition properties.
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19
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Raman MCC, Rizkallah PJ, Simmons R, Donnellan Z, Dukes J, Bossi G, Le Provost GS, Todorov P, Baston E, Hickman E, Mahon T, Hassan N, Vuidepot A, Sami M, Cole DK, Jakobsen BK. Direct molecular mimicry enables off-target cardiovascular toxicity by an enhanced affinity TCR designed for cancer immunotherapy. Sci Rep 2016; 6:18851. [PMID: 26758806 PMCID: PMC4725365 DOI: 10.1038/srep18851] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 11/27/2015] [Indexed: 12/11/2022] Open
Abstract
Natural T-cell responses generally lack the potency to eradicate cancer. Enhanced affinity T-cell receptors (TCRs) provide an ideal approach to target cancer cells, with emerging clinical data showing significant promise. Nevertheless, the risk of off target reactivity remains a key concern, as exemplified in a recent clinical report describing fatal cardiac toxicity, following administration of MAGE-A3 specific TCR-engineered T-cells, mediated through cross-reactivity with an unrelated epitope from the Titin protein presented on cardiac tissue. Here, we investigated the structural mechanism enabling TCR cross-recognition of MAGE-A3 and Titin, and applied the resulting data to rationally design mutants with improved antigen discrimination, providing a proof-of-concept strategy for altering the fine specificity of a TCR towards an intended target antigen. This study represents the first example of direct molecular mimicry leading to clinically relevant fatal toxicity, mediated by a modified enhanced affinity TCR designed for cancer immunotherapy. Furthermore, these data demonstrate that self-antigens that are expressed at high levels on healthy tissue should be treated with extreme caution when designing immuno-therapeutics.
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Affiliation(s)
- Marine C C Raman
- Immunocore Limited, 101 Park Drive, Milton Park, Abingdon, Oxon, OX14 4RX, United Kingdom
| | - Pierre J Rizkallah
- Division of Infection and Immunity, Cardiff University School of Medicine, Henry Wellcome building, Heath Park, Cardiff, CF14 4XN, United Kingdom
| | - Ruth Simmons
- Immunocore Limited, 101 Park Drive, Milton Park, Abingdon, Oxon, OX14 4RX, United Kingdom
| | - Zoe Donnellan
- Immunocore Limited, 101 Park Drive, Milton Park, Abingdon, Oxon, OX14 4RX, United Kingdom
| | - Joseph Dukes
- Immunocore Limited, 101 Park Drive, Milton Park, Abingdon, Oxon, OX14 4RX, United Kingdom
| | - Giovanna Bossi
- Immunocore Limited, 101 Park Drive, Milton Park, Abingdon, Oxon, OX14 4RX, United Kingdom
| | - Gabrielle S Le Provost
- Immunocore Limited, 101 Park Drive, Milton Park, Abingdon, Oxon, OX14 4RX, United Kingdom
| | - Penio Todorov
- Immunocore Limited, 101 Park Drive, Milton Park, Abingdon, Oxon, OX14 4RX, United Kingdom
| | - Emma Baston
- Immunocore Limited, 101 Park Drive, Milton Park, Abingdon, Oxon, OX14 4RX, United Kingdom
| | - Emma Hickman
- Immunocore Limited, 101 Park Drive, Milton Park, Abingdon, Oxon, OX14 4RX, United Kingdom
| | - Tara Mahon
- Immunocore Limited, 101 Park Drive, Milton Park, Abingdon, Oxon, OX14 4RX, United Kingdom
| | - Namir Hassan
- Immunocore Limited, 101 Park Drive, Milton Park, Abingdon, Oxon, OX14 4RX, United Kingdom
| | - Annelise Vuidepot
- Immunocore Limited, 101 Park Drive, Milton Park, Abingdon, Oxon, OX14 4RX, United Kingdom
| | - Malkit Sami
- Immunocore Limited, 101 Park Drive, Milton Park, Abingdon, Oxon, OX14 4RX, United Kingdom
| | - David K Cole
- Division of Infection and Immunity, Cardiff University School of Medicine, Henry Wellcome building, Heath Park, Cardiff, CF14 4XN, United Kingdom
| | - Bent K Jakobsen
- Immunocore Limited, 101 Park Drive, Milton Park, Abingdon, Oxon, OX14 4RX, United Kingdom
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20
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Murray JS. An old Twist in HLA-A: CDR3α Hook up at an R65-joint. Front Immunol 2015; 6:268. [PMID: 26074926 PMCID: PMC4445401 DOI: 10.3389/fimmu.2015.00268] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 05/14/2015] [Indexed: 11/30/2022] Open
Abstract
T-cell ontogeny optimizes the α/β T-cell receptor (TCR) repertoire for recognition of major histocompatibility complex (MHC) class-I/II genetic polymorphism, and co-evolution of TCR germline V-gene segments and the MHC must entail somatic diversity generated in the third complimentary determining regions (CDR3α/β); however, it is still not clear how. Herein, a conspicuous structural link between the V-Jα used by several different TCR [all in complex with the same MHC molecule (HLA-A2)], and a conserved MHC motif (a.a., R65-X-X-K-A-X-S-Q72) is described. We model this R65-joint in detail, and show that the same TCR’s CDR3α loop maintains its CDR2α loop at a distance of ~4 Å from polymorphic amino acid (a.a.) positions of the α-2 helix in all but one of the analyzed crystal structures. Indeed, the pitch of docked TCRs varies as their twist/tilt/sway maintains the R65-joint and peptide contacts. Thus, the R65-joint appears to have poised the HLA-A lineage toward alloreactivity.
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21
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Smith SN, Wang Y, Baylon JL, Singh NK, Baker BM, Tajkhorshid E, Kranz DM. Changing the peptide specificity of a human T-cell receptor by directed evolution. Nat Commun 2014; 5:5223. [PMID: 25376839 PMCID: PMC4225554 DOI: 10.1038/ncomms6223] [Citation(s) in RCA: 20] [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] [Received: 09/04/2014] [Accepted: 09/10/2014] [Indexed: 11/09/2022] Open
Abstract
Binding of a T-cell receptor (TCR) to a peptide/major histocompatibility complex is the key interaction involved in antigen specificity of T cells. The recognition involves up to six complementarity determining regions (CDR) of the TCR. Efforts to examine the structural basis of these interactions and to exploit them in adoptive T-cell therapies has required the isolation of specific T-cell clones and their clonotypic TCRs. Here we describe a strategy using in vitro-directed evolution of a single TCR to change its peptide specificity, thereby avoiding the need to isolate T-cell clones. The human TCR A6, which recognizes the viral peptide Tax/HLA-A2, was converted to TCR variants that recognized the cancer peptide MART1/HLA-A2. Mutational studies and molecular dynamics simulations identified CDR residues that were predicted to be important in the specificity switch. Thus, in vitro engineering strategies alone can be used to discover TCRs with desired specificities.
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Affiliation(s)
- Sheena N. Smith
- Department of Biochemistry, University of Illinois, 600 S. Matthews Ave., Urbana, IL 61801, USA
| | - Yuhang Wang
- Center for Biophysics and Computational Biology, University of Illinois, Urbana, IL 61802, USA
| | - Javier L. Baylon
- Center for Biophysics and Computational Biology, University of Illinois, Urbana, IL 61802, USA
| | - Nishant K. Singh
- Department of Chemistry and Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, 1234 Notre Dame Avenue, South Bend, IN 46557, USA
| | - Brian M. Baker
- Department of Chemistry and Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, 1234 Notre Dame Avenue, South Bend, IN 46557, USA
| | - Emad Tajkhorshid
- Department of Biochemistry, University of Illinois, 600 S. Matthews Ave., Urbana, IL 61801, USA
- Center for Biophysics and Computational Biology, University of Illinois, Urbana, IL 61802, USA
| | - David M. Kranz
- Department of Biochemistry, University of Illinois, 600 S. Matthews Ave., Urbana, IL 61801, USA
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22
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Malecek K, Grigoryan A, Zhong S, Gu WJ, Johnson LA, Rosenberg SA, Cardozo T, Krogsgaard M. Specific increase in potency via structure-based design of a TCR. THE JOURNAL OF IMMUNOLOGY 2014; 193:2587-99. [PMID: 25070852 DOI: 10.4049/jimmunol.1302344] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Adoptive immunotherapy with Ag-specific T lymphocytes is a powerful strategy for cancer treatment. However, most tumor Ags are nonreactive "self" proteins, which presents an immunotherapy design challenge. Recent studies have shown that tumor-specific TCRs can be transduced into normal PBLs, which persist after transfer in ∼30% of patients and effectively destroy tumor cells in vivo. Although encouraging, the limited clinical responses underscore the need for enrichment of T cells with desirable antitumor capabilities prior to patient transfer. In this study, we used structure-based design to predict point mutations of a TCR (DMF5) that enhance its binding affinity for an agonist tumor Ag-MHC (peptide-MHC [pMHC]), Mart-1 (27L)-HLA-A2, which elicits full T cell activation to trigger immune responses. We analyzed the effects of selected TCR point mutations on T cell activation potency and analyzed cross-reactivity with related Ags. Our results showed that the mutated TCRs had improved T cell activation potency while retaining a high degree of specificity. Such affinity-optimized TCRs have demonstrated to be very specific for Mart-1 (27L), the epitope for which they were structurally designed. Although of somewhat limited clinical relevance, these studies open the possibility for future structural-based studies that could potentially be used in adoptive immunotherapy to treat melanoma while avoiding adverse autoimmunity-derived effects.
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Affiliation(s)
- Karolina Malecek
- Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016; Program in Structural Biology, New York University School of Medicine, New York, NY 10016
| | - Arsen Grigoryan
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016
| | - Shi Zhong
- Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016
| | - Wei Jun Gu
- Department of Chemistry, New York University, New York, NY 10012
| | - Laura A Johnson
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892; and
| | - Steven A Rosenberg
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892; and
| | - Timothy Cardozo
- Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016; Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016
| | - Michelle Krogsgaard
- Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016; Program in Structural Biology, New York University School of Medicine, New York, NY 10016; Interdisciplinary Melanoma Cooperative Group, New York University School of Medicine, New York, NY 10016
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23
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Laugel B. Bench, bedside, toolbox: T-cells deliver on every level. Front Immunol 2014; 5:31. [PMID: 24550915 PMCID: PMC3909921 DOI: 10.3389/fimmu.2014.00031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 01/19/2014] [Indexed: 11/13/2022] Open
Affiliation(s)
- Bruno Laugel
- Institute of Infection and Immunity, Cardiff University School of Medicine , Cardiff , UK
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24
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Cole DK, Miles KM, Madura F, Holland CJ, Schauenburg AJA, Godkin AJ, Bulek AM, Fuller A, Akpovwa HJE, Pymm PG, Liddy N, Sami M, Li Y, Rizkallah PJ, Jakobsen BK, Sewell AK. T-cell receptor (TCR)-peptide specificity overrides affinity-enhancing TCR-major histocompatibility complex interactions. J Biol Chem 2013; 289:628-38. [PMID: 24196962 PMCID: PMC3887192 DOI: 10.1074/jbc.m113.522110] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
αβ T-cell receptors (TCRs) engage antigens using complementarity-determining region (CDR) loops that are either germ line-encoded (CDR1 and CDR2) or somatically rearranged (CDR3). TCR ligands compose a presentation platform (major histocompatibility complex (MHC)) and a variable antigenic component consisting of a short “foreign” peptide. The sequence of events when the TCR engages its peptide-MHC (pMHC) ligand remains unclear. Some studies suggest that the germ line elements of the TCR engage the MHC prior to peptide scanning, but this order of binding is difficult to reconcile with some TCR-pMHC structures. Here, we used TCRs that exhibited enhanced pMHC binding as a result of mutations in either CDR2 and/or CDR3 loops, that bound to the MHC or peptide, respectively, to dissect the roles of these loops in stabilizing TCR-pMHC interactions. Our data show that TCR-peptide interactions play a strongly dominant energetic role providing a binding mode that is both temporally and energetically complementary with a system requiring positive selection by self-pMHC in the thymus and rapid recognition of non-self-pMHC in the periphery.
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Affiliation(s)
- David K Cole
- From Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN
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25
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Smith SN, Sommermeyer D, Piepenbrink KH, Blevins SJ, Bernhard H, Uckert W, Baker BM, Kranz DM. Plasticity in the contribution of T cell receptor variable region residues to binding of peptide-HLA-A2 complexes. J Mol Biol 2013; 425:4496-507. [PMID: 23954306 DOI: 10.1016/j.jmb.2013.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 08/05/2013] [Accepted: 08/06/2013] [Indexed: 11/29/2022]
Abstract
One hypothesis accounting for major histocompatibility complex (MHC) restriction by T cell receptors (TCRs) holds that there are several evolutionary conserved residues in TCR variable regions that contact MHC. While this "germline codon" hypothesis is supported by various lines of evidence, it has been difficult to test. The difficulty stems in part from the fact that TCRs exhibit low affinities for pep/MHC, thus limiting the range of binding energies that can be assigned to these key interactions using mutational analyses. To measure the magnitude of binding energies involved, here we used high-affinity TCRs engineered by mutagenesis of CDR3. The TCRs included a high-affinity, MART-1/HLA-A2-specific single-chain TCR and two other high-affinity TCRs that all contain the same Vα region and recognize the same MHC allele (HLA-A2), with different peptides and Vβ regions. Mutational analysis of residues in CDR1 and CDR2 of the three Vα2 regions showed the importance of the key germline codon residue Y51. However, two other proposed key residues showed significant differences among the TCRs in their relative contributions to binding. With the use of single-position, yeast-display libraries in two of the key residues, MART-1/HLA-A2 selections also revealed strong preferences for wild-type germline codon residues, but several alternative residues could also accommodate binding and, hence, MHC restriction. Thus, although a single residue (Y51) could account for a proportion of the energy associated with positive selection (i.e., MHC restriction), there is significant plasticity in requirements for particular side chains in CDR1 and CDR2 and in their relative binding contributions among different TCRs.
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Affiliation(s)
- Sheena N Smith
- Department of Biochemistry, University of Illinois, 600 South Mathews Avenue, Urbana, IL 61801, USA
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