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Xin W, Huang B, Chi X, Liu Y, Xu M, Zhang Y, Li X, Su Q, Zhou Q. Structures of human γδ T cell receptor-CD3 complex. Nature 2024; 630:222-229. [PMID: 38657677 PMCID: PMC11153141 DOI: 10.1038/s41586-024-07439-4] [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: 05/29/2023] [Accepted: 04/18/2024] [Indexed: 04/26/2024]
Abstract
Gamma delta (γδ) T cells, a unique T cell subgroup, are crucial in various immune responses and immunopathology1-3. The γδ T cell receptor (TCR), which is generated by γδ T cells, recognizes a diverse range of antigens independently of the major histocompatibility complex2. The γδ TCR associates with CD3 subunits, initiating T cell activation and holding great potential in immunotherapy4. Here we report the structures of two prototypical human Vγ9Vδ2 and Vγ5Vδ1 TCR-CD3 complexes5,6, revealing two distinct assembly mechanisms that depend on Vγ usage. The Vγ9Vδ2 TCR-CD3 complex is monomeric, with considerable conformational flexibility in the TCRγ-TCRδ extracellular domain and connecting peptides. The length of the connecting peptides regulates the ligand association and T cell activation. A cholesterol-like molecule wedges into the transmembrane region, exerting an inhibitory role in TCR signalling. The Vγ5Vδ1 TCR-CD3 complex displays a dimeric architecture, whereby two protomers nestle back to back through the Vγ5 domains of the TCR extracellular domains. Our biochemical and biophysical assays further corroborate the dimeric structure. Importantly, the dimeric form of the Vγ5Vδ1 TCR is essential for T cell activation. These findings reveal organizing principles of the γδ TCR-CD3 complex, providing insights into the unique properties of γδ TCR and facilitating immunotherapeutic interventions.
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MESH Headings
- Humans
- CD3 Complex/chemistry
- CD3 Complex/immunology
- CD3 Complex/metabolism
- CD3 Complex/ultrastructure
- Cholesterol/metabolism
- Cholesterol/chemistry
- Cryoelectron Microscopy
- Ligands
- Lymphocyte Activation/immunology
- Models, Molecular
- Protein Domains
- Protein Multimerization
- Receptors, Antigen, T-Cell, gamma-delta/chemistry
- Receptors, Antigen, T-Cell, gamma-delta/immunology
- Receptors, Antigen, T-Cell, gamma-delta/metabolism
- Receptors, Antigen, T-Cell, gamma-delta/ultrastructure
- T-Lymphocytes/chemistry
- T-Lymphocytes/cytology
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- Signal Transduction
- Cell Membrane/chemistry
- Cell Membrane/metabolism
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Affiliation(s)
- Weizhi Xin
- Research Center for Industries of the Future, Center for Infectious Disease Research, Zhejiang Key Laboratory of Structural Biology, School of Life Sciences, Westlake University, Hangzhou, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China
| | - Bangdong Huang
- Research Center for Industries of the Future, Center for Infectious Disease Research, Zhejiang Key Laboratory of Structural Biology, School of Life Sciences, Westlake University, Hangzhou, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China
| | - Ximin Chi
- Research Center for Industries of the Future, Center for Infectious Disease Research, Zhejiang Key Laboratory of Structural Biology, School of Life Sciences, Westlake University, Hangzhou, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Science, Xiamen University, Xiamen, China
| | - Yuehua Liu
- Research Center for Industries of the Future, Center for Infectious Disease Research, Zhejiang Key Laboratory of Structural Biology, School of Life Sciences, Westlake University, Hangzhou, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China
| | - Mengjiao Xu
- Research Center for Industries of the Future, Center for Infectious Disease Research, Zhejiang Key Laboratory of Structural Biology, School of Life Sciences, Westlake University, Hangzhou, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China
| | - Yuanyuan Zhang
- Research Center for Industries of the Future, Center for Infectious Disease Research, Zhejiang Key Laboratory of Structural Biology, School of Life Sciences, Westlake University, Hangzhou, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China
| | - Xu Li
- Research Center for Industries of the Future, Center for Infectious Disease Research, Zhejiang Key Laboratory of Structural Biology, School of Life Sciences, Westlake University, Hangzhou, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China
| | - Qiang Su
- Research Center for Industries of the Future, Center for Infectious Disease Research, Zhejiang Key Laboratory of Structural Biology, School of Life Sciences, Westlake University, Hangzhou, China.
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, China.
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China.
| | - Qiang Zhou
- Research Center for Industries of the Future, Center for Infectious Disease Research, Zhejiang Key Laboratory of Structural Biology, School of Life Sciences, Westlake University, Hangzhou, China.
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, China.
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China.
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2
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Notti RQ, Yi F, Heissel S, Bush MW, Molvi Z, Das P, Molina H, Klebanoff CA, Walz T. The resting and ligand-bound states of the membrane-embedded human T-cell receptor-CD3 complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.22.554360. [PMID: 37662363 PMCID: PMC10473723 DOI: 10.1101/2023.08.22.554360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
The T-cell receptor (TCR) is central to the ligand-dependent activation of T lymphocytes and as such orchestrates both adaptive and pathologic immune processes. However, major questions remain regarding the structure and function of the human TCR. Here, we present cryogenic electron microscopy structures for the unliganded and HLA-bound human TCR-CD3 complex in nanodiscs that provide a native-like lipid environment. The unliganded structures reveal two related conformations that are distinct from its structure in detergent. These new "closed and compacted" conformations afford insights into the interactions between the TCR-CD3 and the membrane, including conserved surface patches that make extensive outer leaflet contact, and suggest novel conformational regulation by glycans. We show that the closed/compacted conformations, not the extended one previously reported in detergent, represent the unliganded resting state for the TCR-CD3 in vivo, underscoring the importance of structural interrogation of membrane proteins in native-like environments. By contrast, the structure of the HLA-bound complex in nanodiscs is in an open and extended conformation, showing that physiologic ligand binding is sufficient to induce substantial conformational change in the TCR-CD3 complex. We use conformation-locking disulfide mutants to show that ectodomain opening is necessary for maximal ligand-dependent TCR-CD3 activation, demonstrating that TCR-intrinsic conformational change is necessary for full TCR-CD3 activation and opening numerous avenues for immunoreceptor engineering.
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3
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Rogers J, Bajur AT, Salaita K, Spillane KM. Mechanical control of antigen detection and discrimination by T and B cell receptors. Biophys J 2024:S0006-3495(24)00347-3. [PMID: 38794795 DOI: 10.1016/j.bpj.2024.05.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 05/10/2024] [Accepted: 05/21/2024] [Indexed: 05/26/2024] Open
Abstract
The adaptive immune response is orchestrated by just two cell types, T cells and B cells. Both cells possess the remarkable ability to recognize virtually any antigen through their respective antigen receptors-the T cell receptor (TCR) and B cell receptor (BCR). Despite extensive investigations into the biochemical signaling events triggered by antigen recognition in these cells, our ability to predict or control the outcome of T and B cell activation remains elusive. This challenge is compounded by the sensitivity of T and B cells to the biophysical properties of antigens and the cells presenting them-a phenomenon we are just beginning to understand. Recent insights underscore the central role of mechanical forces in this process, governing the conformation, signaling activity, and spatial organization of TCRs and BCRs within the cell membrane, ultimately eliciting distinct cellular responses. Traditionally, T cells and B cells have been studied independently, with researchers working in parallel to decipher the mechanisms of activation. While these investigations have unveiled many overlaps in how these cell types sense and respond to antigens, notable differences exist. To fully grasp their biology and harness it for therapeutic purposes, these distinctions must be considered. This review compares and contrasts the TCR and BCR, placing emphasis on the role of mechanical force in regulating the activity of both receptors to shape cellular and humoral adaptive immune responses.
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Affiliation(s)
- Jhordan Rogers
- Department of Chemistry, Emory University, Atlanta, Georgia
| | - Anna T Bajur
- Department of Physics, King's College London, London, United Kingdom; Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Khalid Salaita
- Department of Chemistry, Emory University, Atlanta, Georgia; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
| | - Katelyn M Spillane
- Department of Physics, King's College London, London, United Kingdom; Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom; Department of Life Sciences, Imperial College London, London, United Kingdom.
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4
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Wang H, Wu X, Sun Y, Liu A, He Y, Xu Z, Lu Y, Zhan C. A natural IgM hitchhiking strategy for delivery of cancer nanovaccines to splenic marginal zone B cells. J Control Release 2024; 368:208-218. [PMID: 38395156 DOI: 10.1016/j.jconrel.2024.02.029] [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: 10/22/2023] [Revised: 02/18/2024] [Accepted: 02/20/2024] [Indexed: 02/25/2024]
Abstract
B cell-targeted cancer vaccines are receiving increasing attention in immunotherapy due to the combined antibody-secreting and antigen-presenting functions. In this study, we propose a natural IgM-hitchhiking delivery strategy to co-deliver tumor antigens and adjuvants to splenic marginal zone B (MZB) cells. We constructed nanovaccines (FA-sLip/OVA/MPLA) consisting of classical folic acid (FA)-conjugated liposomes co-loaded with ovalbumin (OVA) and toll-like receptor 4 agonists, MPLA. We found that natural IgM absorption could be manipulated at the bio-nano interface on FA-sLip/OVA/MPLA, enabling targeted delivery to splenic MZB cells. Systemic administration of FA-sLip/OVA/MPLA effectively activated splenic MZB cells via IgM-mediated multiplex pathways, eliciting antigen-specific humoral and cytotoxic T lymphocyte responses, and ultimately retarding E.G7-OVA tumor growth. In addition, combining FA-sLip/OVA/MPLA immunization with anti-PD-1 treatments showed improved antitumor efficiency. Overall, this natural IgM-hitchhiking delivery strategy holds great promise for efficient, splenic MZB cell-targeted delivery of cancer vaccines in future applications.
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Affiliation(s)
- Huan Wang
- Department of Pharmaceutical Sciences, School of Pharmacy, Naval Medical University, Shanghai 200433, PR China
| | - Xiying Wu
- Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai 200433, PR China
| | - Yuhan Sun
- Department of Pharmaceutical Sciences, School of Pharmacy, Naval Medical University, Shanghai 200433, PR China
| | - Anze Liu
- Department of Pharmaceutical Sciences, School of Pharmacy, Naval Medical University, Shanghai 200433, PR China
| | - Yingying He
- Department of Pharmaceutical Sciences, School of Pharmacy, Naval Medical University, Shanghai 200433, PR China
| | - Ziyi Xu
- Department of Pharmaceutical Sciences, School of Pharmacy, Naval Medical University, Shanghai 200433, PR China
| | - Ying Lu
- Department of Pharmaceutical Sciences, School of Pharmacy, Naval Medical University, Shanghai 200433, PR China.
| | - Changyou Zhan
- Department of Pharmacy, Shanghai Pudong Hospital & Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai 201399, PR China.
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5
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Sun W, Zhu C, Li Y, Wu X, Shi X, Liu W. B cell activation and autoantibody production in autoimmune diseases. Best Pract Res Clin Rheumatol 2024:101936. [PMID: 38326197 DOI: 10.1016/j.berh.2024.101936] [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: 01/03/2024] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 02/09/2024]
Abstract
B cells are central players in the immune system, responsible for producing antibodies and modulating immune responses. This review explores the intricate relationship between aberrant B cell activation and the development of autoimmune diseases, emphasizing the essential role of B cells in these conditions. We also summarize B cell receptor signaling and Toll-like receptor signaling in B cell activation, as well as their association with autoimmune diseases, shedding light on the molecular mechanisms behind these associations. Additionally, we explore the clinical observations involving B cell activation and their significance in autoimmune disease management. Various clinical studies related to B cell-targeted therapies are also discussed, offering insights into potential avenues for improving treatment strategies. Overall, this review serves as a resource for researchers and clinicians in the field of immunology and autoimmune diseases, providing a general view of B cell signaling and its role in autoimmunity.
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Affiliation(s)
- Wenbo Sun
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Institute for Immunology, China Ministry of Education Key Laboratory of Protein Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, No. 1, Qinghua Yuan, New Biology Bldg, Haidian District, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China; The First Affiliated Hospital of Anhui Medical University and Institute of Clinical Immunology, Anhui Medical University, Hefei, 230032, China.
| | - Can Zhu
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Institute for Immunology, China Ministry of Education Key Laboratory of Protein Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, No. 1, Qinghua Yuan, New Biology Bldg, Haidian District, Beijing, 100084, China.
| | - Yuxin Li
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Institute for Immunology, China Ministry of Education Key Laboratory of Protein Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, No. 1, Qinghua Yuan, New Biology Bldg, Haidian District, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China.
| | - Xinfeng Wu
- Department of Rheumatology and Immunology, The First Affiliated Hospital, and College of Clinical Medicine of Henan University of Science and Technology, No. 636, Guanlin Road, 471000, Luoyang, China.
| | - Xiaofei Shi
- Department of Rheumatology and Immunology, The First Affiliated Hospital, and College of Clinical Medicine of Henan University of Science and Technology, No. 636, Guanlin Road, 471000, Luoyang, China.
| | - Wanli Liu
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Institute for Immunology, China Ministry of Education Key Laboratory of Protein Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, No. 1, Qinghua Yuan, New Biology Bldg, Haidian District, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China; The First Affiliated Hospital of Anhui Medical University and Institute of Clinical Immunology, Anhui Medical University, Hefei, 230032, China.
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6
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Guo D, De Sciscio ML, Chi-Fung Ng J, Fraternali F. Modelling the assembly and flexibility of antibody structures. Curr Opin Struct Biol 2024; 84:102757. [PMID: 38118364 DOI: 10.1016/j.sbi.2023.102757] [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: 10/13/2023] [Revised: 11/29/2023] [Accepted: 11/30/2023] [Indexed: 12/22/2023]
Abstract
Antibodies are large protein assemblies capable of both specifically recognising antigens and engaging with other proteins and receptors to coordinate immune action. Traditionally, structural studies have been dedicated to antibody variable regions, but efforts to determine and model full-length antibody structures are emerging. Here we review the current knowledge on modelling the structures of antibody assemblies, focusing on their conformational flexibility and the challenge this poses to obtaining and evaluating structural models. Integrative modelling approaches, combining experiments (cryo-electron microscopy, mass spectrometry, etc.) and computational methods (molecular dynamics simulations, deep-learning based approaches, etc.), hold the promise to map the complex conformational landscape of full-length antibody structures.
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Affiliation(s)
- Dongjun Guo
- Institute of Structural and Molecular Biology, University College London, Darwin Building, Gower Street, London, WC1E 6BT, United Kingdom; Randall Centre for Cell & Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, SE1 1UL, United Kingdom
| | - Maria Laura De Sciscio
- Institute of Structural and Molecular Biology, University College London, Darwin Building, Gower Street, London, WC1E 6BT, United Kingdom; Department of Chemistry, Sapienza University of Rome, P.le A. Moro 5, Rome, 00185, Italy
| | - Joseph Chi-Fung Ng
- Institute of Structural and Molecular Biology, University College London, Darwin Building, Gower Street, London, WC1E 6BT, United Kingdom
| | - Franca Fraternali
- Institute of Structural and Molecular Biology, University College London, Darwin Building, Gower Street, London, WC1E 6BT, United Kingdom.
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7
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Kissel T, Derksen VFAM, Bentlage AEH, Koeleman C, Hafkenscheid L, van der Woude D, Wuhrer M, Vidarsson G, Toes REM. N-linked Fc glycosylation is not required for IgG-B-cell receptor function in a GC-derived B-cell line. Nat Commun 2024; 15:393. [PMID: 38195612 PMCID: PMC10776614 DOI: 10.1038/s41467-023-44468-5] [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: 03/31/2023] [Accepted: 12/14/2023] [Indexed: 01/11/2024] Open
Abstract
IgG secreted by B cells carry asparagine N(297)-linked glycans in the fragment crystallizable (Fc) region. Changes in Fc glycosylation are related to health or disease and are functionally relevant, as IgG without Fc glycans cannot bind to Fcɣ receptors or complement factors. However, it is currently unknown whether ɣ-heavy chain (ɣHC) glycans also influence the function of membrane-bound IgG-B-cell receptors (BCR) and thus the outcome of the B-cell immune response. Here, we show in a germinal center (GC)-derived human B-cell line that ɣHC glycans do not affect membrane expression of IgG-BCRs. Furthermore, antigen binding or other BCR-facilitated mechanisms appear unaffected, including BCR downmodulation or BCR-mediated signaling. As expected, secreted IgG lacking Fc glycosylation is unable to carry out effector functions. Together, these observations indicate that IgG-Fc glycosylation serves as a mechanism to control the effector functions of antibodies, but does not regulate the activation of IgG-switched B cells, as its absence had no apparent impact on BCR function.
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Affiliation(s)
- Theresa Kissel
- Department of Rheumatology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands.
| | - Veerle F A M Derksen
- Department of Rheumatology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Arthur E H Bentlage
- Department of Experimental Immunohematology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam, 1006 AD, Amsterdam, The Netherlands
| | - Carolien Koeleman
- Center for Proteomics and Metabolomics, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Lise Hafkenscheid
- Department of Rheumatology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Diane van der Woude
- Department of Rheumatology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Manfred Wuhrer
- Center for Proteomics and Metabolomics, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Gestur Vidarsson
- Department of Experimental Immunohematology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam, 1006 AD, Amsterdam, The Netherlands
| | - René E M Toes
- Department of Rheumatology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands.
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8
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Chen K, Jiang M, Liu J, Huang D, Yang YR. DNA nanostructures as biomolecular scaffolds for antigen display. WILEY INTERDISCIPLINARY REVIEWS. NANOMEDICINE AND NANOBIOTECHNOLOGY 2024; 16:e1921. [PMID: 37562787 DOI: 10.1002/wnan.1921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 07/17/2023] [Accepted: 07/18/2023] [Indexed: 08/12/2023]
Abstract
Nanoparticle-based vaccines offer a multivalent approach for antigen display, efficiently activating T and B cells in the lymph nodes. Among various nanoparticle design strategies, DNA nanotechnology offers an innovative alternative platform, featuring high modularity, spatial addressing, nanoscale regulation, high functional group density, and lower self-antigenicity. This review delves into the potential of DNA nanostructures as biomolecular scaffolds for antigen display, addressing: (1) immunological mechanisms behind nanovaccines and commonly used nanoparticles in their design, (2) techniques for characterizing protein NP-antigen complexes, (3) advancements in DNA nanotechnology and DNA-protein assembly approach, (4) strategies for precise antigen presentation on DNA scaffolds, and (5) current applications and future possibilities of DNA scaffolds in antigen display. This analysis aims to highlight the transformative potential of DNA nanoscaffolds in immunology and vaccinology. This article is categorized under: Biology-Inspired Nanomaterials > Nucleic Acid-Based Structures Biology-Inspired Nanomaterials > Protein and Virus-Based Structures.
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Affiliation(s)
- Kun Chen
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, China
- Materials Science and Engineering, Beijing University of Chemical Technology, Beijing, China
| | - Ming Jiang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, China
| | - Jin Liu
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, China
- Tangdu Hospital, Air Force Medical University, Xi'an, China
| | - Deli Huang
- Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Yuhe R Yang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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9
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Seon BK, Okazaki M, Duzen J, Matsuno F, Goey AKL, Maguire O. Identification of unique molecular heterogeneity of human CD79, the signaling component of the human B cell antigen receptor (BCR), and synergistic potentiation of the CD79-targeted therapy of B cell tumors by co-targeting of CD79a and CD79b. Leuk Res 2024; 136:107436. [PMID: 38232613 PMCID: PMC10906460 DOI: 10.1016/j.leukres.2024.107436] [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: 11/13/2023] [Revised: 01/02/2024] [Accepted: 01/04/2024] [Indexed: 01/19/2024]
Abstract
We identified unique molecular heterogeneity of CD79 of human B cell antigen receptor (BCR) that may open a new approach to the ongoing CD79b-targeted therapy of B cell tumors. The primary purpose of the present study is to gain new information valuable for the enhanced CD79-targeted therapy. The molecular heterogeneity of CD79 was identified by sequential immunoprecipitation of BCR by use of anti-CD79b monoclonal antibody (mAb) SN8 and anti-CD79a mAb SN8b. SN8 is the antibody component of polatuzumab vedotin, an anti-CD79b antibody drug conjugate, that has been widely used for therapy of diffuse large B-cell lymphoma (DLBCL). The sequential immunoprecipitation shows that anti-CD79b mAb will be able to react only with a subgroup of CD79 molecules while anti-CD79a mAb will react with another subgroup of CD79 molecules; CD79 is a disulfide-linked heterodimer of CD79a and CD79b. Therapeutic study of SCID mice bearing human B-cell tumor shows synergistic potentiation by co-targeting CD79b and CD79a. Furthermore, simultaneous targeting of PD-1 strongly potentiates CD79a/CD79b-targeted therapy of B cell tumors. Flow cytometry analyses of CD79a/CD79b on malignant B cells of patients may provide a method for selection of the candidate patients for the CD79a/CD79b dual targeting therapy.
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Affiliation(s)
- Ben K Seon
- Department of Immunology, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA.
| | - Morihiro Okazaki
- Department of Immunology, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Jill Duzen
- Department of Immunology, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Fumihiko Matsuno
- Department of Immunology, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Andrew K L Goey
- Bioanalytics, Metabolomics and Pharmacokinetics (BMPK) Shared Resource, and Department of Pharmacology and Therapeutics, Rpswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Orla Maguire
- Flow and Image Cytometry Shared Resource, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
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10
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Tkachenko A, Kupcova K, Havranek O. B-Cell Receptor Signaling and Beyond: The Role of Igα (CD79a)/Igβ (CD79b) in Normal and Malignant B Cells. Int J Mol Sci 2023; 25:10. [PMID: 38203179 PMCID: PMC10779339 DOI: 10.3390/ijms25010010] [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: 11/13/2023] [Revised: 12/11/2023] [Accepted: 12/11/2023] [Indexed: 01/12/2024] Open
Abstract
B-cell receptor (BCR) is a B cell hallmark surface complex regulating multiple cellular processes in normal as well as malignant B cells. Igα (CD79a)/Igβ (CD79b) are essential components of BCR that are indispensable for its functionality, signal initiation, and signal transduction. CD79a/CD79b-mediated BCR signaling is required for the survival of normal as well as malignant B cells via a wide signaling network. Recent studies identified the great complexity of this signaling network and revealed the emerging role of CD79a/CD79b in signal integration. In this review, we have focused on functional features of CD79a/CD79b, summarized signaling consequences of CD79a/CD79b post-translational modifications, and highlighted specifics of CD79a/CD79b interactions within BCR and related signaling cascades. We have reviewed the complex role of CD79a/CD79b in multiple aspects of normal B cell biology and how is the normal BCR signaling affected by lymphoid neoplasms associated CD79A/CD79B mutations. We have also summarized important unresolved questions and highlighted issues that remain to be explored for better understanding of CD79a/CD79b-mediated signal transduction and the eventual identification of additional therapeutically targetable BCR signaling vulnerabilities.
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Affiliation(s)
- Anton Tkachenko
- BIOCEV, First Faculty of Medicine, Charles University, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Kristyna Kupcova
- BIOCEV, First Faculty of Medicine, Charles University, Prumyslova 595, 252 50 Vestec, Czech Republic
- First Department of Internal Medicine–Hematology, General University Hospital and First Faculty of Medicine, Charles University, 128 08 Prague, Czech Republic
| | - Ondrej Havranek
- BIOCEV, First Faculty of Medicine, Charles University, Prumyslova 595, 252 50 Vestec, Czech Republic
- First Department of Internal Medicine–Hematology, General University Hospital and First Faculty of Medicine, Charles University, 128 08 Prague, Czech Republic
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11
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Bhanja A, Seeley-Fallen MK, Lazzaro M, Upadhyaya A, Song W. N-WASP-dependent branched actin polymerization attenuates B-cell receptor signaling by increasing the molecular density of receptor clusters. eLife 2023; 12:RP87833. [PMID: 38085658 PMCID: PMC10715734 DOI: 10.7554/elife.87833] [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] [Indexed: 12/18/2023] Open
Abstract
Antigen-induced B-cell receptor (BCR) signaling is critical for initiating and regulating B-cell activation. The actin cytoskeleton plays essential roles in BCR signaling. Upon encountering cell-surface antigens, actin-driven B-cell spreading amplifies signaling, while B-cell contraction following spreading leads to signal attenuation. However, the mechanism by which actin dynamics switch BCR signaling from amplification to attenuation is unknown. Here, we show that Arp2/3-mediated branched actin polymerization is required for mouse splenic B-cell contraction. Contracting B-cells generate centripetally moving actin foci from lamellipodial F-actin networks in the plasma membrane region contacting antigen-presenting surfaces. Actin polymerization driven by N-WASP, but not WASP, initiates these actin foci and facilitates non-muscle myosin II recruitment to the contact zone, creating actomyosin ring-like structures. B-cell contraction increases BCR molecular density in individual clusters, leading to decreased BCR phosphorylation. Increased BCR molecular density reduced levels of the stimulatory kinase Syk, the inhibitory phosphatase SHIP-1, and their phosphorylated forms in individual BCR clusters. These results suggest that N-WASP-activated Arp2/3, coordinating with myosin, generates centripetally moving foci and contractile actomyosin ring-like structures from lamellipodial networks, enabling contraction. B-cell contraction attenuates BCR signaling by pushing out both stimulatory kinases and inhibitory phosphatases from BCR clusters, providing novel insights into actin-facilitated signal attenuation.
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Affiliation(s)
- Anshuman Bhanja
- Department of Cell Biology and Molecular Genetics, University of MarylandCollege ParkUnited States
| | - Margaret K Seeley-Fallen
- Department of Cell Biology and Molecular Genetics, University of MarylandCollege ParkUnited States
| | - Michelle Lazzaro
- Department of Cell Biology and Molecular Genetics, University of MarylandCollege ParkUnited States
| | - Arpita Upadhyaya
- Biophysics Program, University of MarylandCollege ParkUnited States
- Department of Physics, University of MarylandCollege ParkUnited States
- Institute for Physical Science and Technology, University of MarylandCollege ParkUnited States
| | - Wenxia Song
- Department of Cell Biology and Molecular Genetics, University of MarylandCollege ParkUnited States
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12
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Holborough-Kerkvliet MD, Mucignato G, Moons SJ, Psomiadou V, Konada RSR, Pedowitz NJ, Pratt MR, Kissel T, Koeleman CAM, Tjokrodirijo RTN, van Veelen PA, Huizinga T, van Schie KAJ, Wuhrer M, Kohler JJ, Bonger KM, Boltje TJ, Toes REM. A photoaffinity glycan-labeling approach to investigate immunoglobulin glycan-binding partners. Glycobiology 2023; 33:732-744. [PMID: 37498177 PMCID: PMC10627247 DOI: 10.1093/glycob/cwad055] [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: 04/28/2023] [Revised: 06/13/2023] [Accepted: 06/30/2023] [Indexed: 07/28/2023] Open
Abstract
Glycans play a pivotal role in biology. However, because of the low-affinity of glycan-protein interactions, many interaction pairs remain unknown. Two important glycoproteins involved in B-cell biology are the B-cell receptor and its secreted counterpart, antibodies. It has been indicated that glycans expressed by these B-cell-specific molecules can modulate immune activation via glycan-binding proteins. In several autoimmune diseases, an increased prevalence of variable domain glycosylation of IgG autoantibodies has been observed. Especially, the hallmarking autoantibodies in rheumatoid arthritis, anti-citrullinated protein antibodies, carry a substantial amount of variable domain glycans. The variable domain glycans expressed by these autoantibodies are N-linked, complex-type, and α2-6 sialylated, and B-cell receptors carrying variable domain glycans have been hypothesized to promote selection of autoreactive B cells via interactions with glycan-binding proteins. Here, we use the anti-citrullinated protein antibody response as a prototype to study potential in solution and in situ B-cell receptor-variable domain glycan interactors. We employed SiaDAz, a UV-activatable sialic acid analog carrying a diazirine moiety that can form covalent bonds with proximal glycan-binding proteins. We show, using oligosaccharide engineering, that SiaDAz can be readily incorporated into variable domain glycans of both antibodies and B-cell receptors. Our data show that antibody variable domain glycans are able to interact with inhibitory receptor, CD22. Interestingly, although we did not detect this interaction on the cell surface, we captured CD79 β glycan-B-cell receptor interactions. These results show the utility of combining photoaffinity labeling and oligosaccharide engineering for identifying antibody and B-cell receptor interactions and indicate that variable domain glycans appear not to be lectin cis ligands in our tested conditions.
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Affiliation(s)
| | - Greta Mucignato
- Department of Rheumatology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Sam J Moons
- Department of Synthetic Organic Chemistry, Radboud University, Toernooiveld 1, Mercator III, 6525 ED, Nijmegen, The Netherlands
| | - Venetia Psomiadou
- Department of Synthetic Organic Chemistry, Radboud University, Toernooiveld 1, Mercator III, 6525 ED, Nijmegen, The Netherlands
| | - Rohit S R Konada
- Department of Biochemistry, University of Texas Southwestern, 5323 Harry Hines Boulevard, Dallas, TX 75390-09185, United States
| | - Nichole J Pedowitz
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, United States
| | - Matthew R Pratt
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, United States
| | - Theresa Kissel
- Department of Rheumatology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Carolien A M Koeleman
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Rayman T N Tjokrodirijo
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Petrus A van Veelen
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Thomas Huizinga
- Department of Rheumatology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Karin A J van Schie
- Department of Rheumatology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Manfred Wuhrer
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Jennifer J Kohler
- Department of Biochemistry, University of Texas Southwestern, 5323 Harry Hines Boulevard, Dallas, TX 75390-09185, United States
| | - Kimberly M Bonger
- Department of Synthetic Organic Chemistry, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Thomas J Boltje
- Department of Synthetic Organic Chemistry, Radboud University, Toernooiveld 1, Mercator III, 6525 ED, Nijmegen, The Netherlands
| | - Reinaldus E M Toes
- Department of Rheumatology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
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13
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Gu H, Fu Y, Yu B, Luo L, Kang D, Xie M, Jing Y, Chen Q, Zhang X, Lai J, Guan F, Forsman H, Shi J, Yang L, Lei J, Du X, Zhang X, Liu C. Ultra-high static magnetic fields cause immunosuppression through disrupting B-cell peripheral differentiation and negatively regulating BCR signaling. MedComm (Beijing) 2023; 4:e379. [PMID: 37789963 PMCID: PMC10542999 DOI: 10.1002/mco2.379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 08/16/2023] [Accepted: 08/24/2023] [Indexed: 10/05/2023] Open
Abstract
To increase the imaging resolution and detection capability, the field strength of static magnetic fields (SMFs) in magnetic resonance imaging (MRI) has significantly increased in the past few decades. However, research on the side effects of high magnetic field is still very inadequate and the effects of SMF above 1 T (Tesla) on B cells have never been reported. Here, we show that 33.0 T ultra-high SMF exposure causes immunosuppression and disrupts B cell differentiation and signaling. 33.0 T SMF treatment resulted in disturbance of B cell peripheral differentiation and antibody secretion and reduced the expression of IgM on B cell membrane, and these might be intensity dependent. In addition, mice exposed to 33.0 T SMF showed inhibition on early activation of B cells, including B cell spreading, B cell receptor clustering and signalosome recruitment, and depression of both positive and negative molecules in the proximal BCR signaling, as well as impaired actin reorganization. Sequencing and gene enrichment analysis showed that SMF stimulation also affects splenic B cells' transcriptome and metabolic pathways. Therefore, in the clinical application of MRI, we should consider the influence of SMF on the immune system and choose the optimal intensity for treatment.
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Affiliation(s)
- Heng Gu
- Department of Pathogen BiologySchool of Basic MedicineTongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious DiseaseHuazhong University of Science and TechnologyWuhanChina
| | - Yufan Fu
- Department of Pathogen BiologySchool of Basic MedicineTongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious DiseaseHuazhong University of Science and TechnologyWuhanChina
| | - Biao Yu
- High Magnetic Field LaboratoryHefei Institutes of Physical ScienceChinese Academy of SciencesHefeiAnhuiChina
| | - Li Luo
- Department of Pathogen BiologySchool of Basic MedicineTongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious DiseaseHuazhong University of Science and TechnologyWuhanChina
| | - Danqing Kang
- Department of Pathogen BiologySchool of Basic MedicineTongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious DiseaseHuazhong University of Science and TechnologyWuhanChina
| | - Miaomiao Xie
- Department of Pathogen BiologySchool of Basic MedicineTongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious DiseaseHuazhong University of Science and TechnologyWuhanChina
| | - Yukai Jing
- Department of Pathogen BiologySchool of Basic MedicineTongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious DiseaseHuazhong University of Science and TechnologyWuhanChina
| | - Qiuyue Chen
- Department of Pathogen BiologySchool of Basic MedicineTongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious DiseaseHuazhong University of Science and TechnologyWuhanChina
| | - Xin Zhang
- GeneMind Biosciences Company LimitedShenzhenChina
| | - Juan Lai
- GeneMind Biosciences Company LimitedShenzhenChina
| | - Fei Guan
- Department of Pathogen BiologySchool of Basic MedicineTongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious DiseaseHuazhong University of Science and TechnologyWuhanChina
| | - Huamei Forsman
- Department of Rheumatology and Inflammation ResearchInstitute of MedicineSahlgrenska AcademyUniversity of GothenburgGoteborgSweden
| | - Junming Shi
- Department of Pathogen BiologySchool of Basic MedicineTongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious DiseaseHuazhong University of Science and TechnologyWuhanChina
| | - Lu Yang
- Department of Pathogen BiologySchool of Basic MedicineTongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious DiseaseHuazhong University of Science and TechnologyWuhanChina
| | - Jiahui Lei
- Department of Pathogen BiologySchool of Basic MedicineTongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious DiseaseHuazhong University of Science and TechnologyWuhanChina
| | - Xingrong Du
- Shanghai Key Laboratory of Metabolic Remodeling and HealthInstitute of Metabolism and Integrative BiologyFudan UniversityShanghaiChina
| | - Xin Zhang
- High Magnetic Field LaboratoryHefei Institutes of Physical ScienceChinese Academy of SciencesHefeiAnhuiChina
- Institutes of Physical Science and Information TechnologyAnhui UniversityHefeiAnhuiChina
| | - Chaohong Liu
- Department of Pathogen BiologySchool of Basic MedicineTongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious DiseaseHuazhong University of Science and TechnologyWuhanChina
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14
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Schoenfeld K, Harwardt J, Habermann J, Elter A, Kolmar H. Conditional activation of an anti-IgM antibody-drug conjugate for precise B cell lymphoma targeting. Front Immunol 2023; 14:1258700. [PMID: 37841262 PMCID: PMC10569071 DOI: 10.3389/fimmu.2023.1258700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 09/07/2023] [Indexed: 10/17/2023] Open
Abstract
Cancerous B cells are almost indistinguishable from their non-malignant counterparts regarding their surface antigen expression. Accordingly, the challenge to be faced consists in elimination of the malignant B cell population while maintaining a functional adaptive immune system. Here, we present an IgM-specific antibody-drug conjugate masked by fusion of the epitope-bearing IgM constant domain. Antibody masking impaired interaction with soluble pentameric as well as cell surface-expressed IgM molecules rendering the antibody cytotoxically inactive. Binding capacity of the anti-IgM antibody drug conjugate was restored upon conditional protease-mediated demasking which consequently enabled target-dependent antibody internalization and subsequent induction of apoptosis in malignant B cells. This easily adaptable approach potentially provides a novel mechanism of clonal B cell lymphoma eradication to the arsenal available for non-Hodgkin's lymphoma treatment.
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Affiliation(s)
- Katrin Schoenfeld
- Institute for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Germany
| | - Julia Harwardt
- Institute for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Germany
| | - Jan Habermann
- Institute for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Germany
| | - Adrian Elter
- Institute for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Germany
| | - Harald Kolmar
- Institute for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Germany
- Centre for Synthetic Biology, Technical University of Darmstadt, Darmstadt, Germany
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15
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Reth M. Discovering immunoreceptor coupling and organization motifs. Front Immunol 2023; 14:1253412. [PMID: 37731510 PMCID: PMC10507400 DOI: 10.3389/fimmu.2023.1253412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 08/11/2023] [Indexed: 09/22/2023] Open
Abstract
The recently determined cryo-EM structures of the T cell antigen receptor (TCR) and B cell antigen receptor (BCR) show in molecular details the interactions of the ligand-binding part with the signaling subunits but they do not reveal the signaling mechanism of these antigen receptors. Without knowing the molecular basis of antigen sensing by these receptors, a rational design of optimal vaccines is not possible. The existence of conserved amino acids (AAs) that are not involved in the subunit interaction suggests that antigen receptors form higher complexes and/or have lateral interactors that control their activity. Here, I describe evolutionary conserved leucine zipper (LZ) motifs within the transmembrane domains (TMD) of antigen and coreceptor components that are likely to be involved in the oligomerization and lateral interaction of antigen receptor complexes on T and B cells. These immunoreceptor coupling and organization motifs (ICOMs) are also found within the TMDs of other important receptor types and viral envelope proteins. This discovery suggests that antigen receptors do not function as isolated entities but rather as part of an ICOM-based interactome that controls their nanoscale organization on resting cells and their dynamic remodeling on activated lymphocytes.
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Affiliation(s)
- Michael Reth
- Department of Molecular Immunology, Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Signaling Research Centers CIBSS and BIOSS, University of Freiburg, Freiburg, Germany
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16
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Bhanja A, Seeley-Fallen MK, Lazzaro M, Upadhyaya A, Song W. N-WASP-dependent branched actin polymerization attenuates B-cell receptor signaling by increasing the molecular density of receptor clusters. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.14.532631. [PMID: 36993351 PMCID: PMC10055065 DOI: 10.1101/2023.03.14.532631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Antigen-induced B-cell receptor (BCR) signaling is critical for initiating and regulating B-cell activation. The actin cytoskeleton plays essential roles in BCR signaling. Upon encountering cell-surface antigens, actin-driven B-cell spreading amplifies signaling, while B-cell contraction following spreading leads to signal attenuation. However, the mechanism by which actin dynamics switch BCR signaling from amplification to attenuation is unknown. Here, we show that Arp2/3-mediated branched actin polymerization is required for B-cell contraction. Contracting B-cells generate centripetally moving actin foci from lamellipodial F-actin networks in the B-cell plasma membrane region contacting antigen-presenting surfaces. Actin polymerization driven by N-WASP, but not WASP, initiates these actin foci and facilitates non-muscle myosin II recruitment to the contact zone, creating actomyosin ring-like structures. Furthermore, B-cell contraction increases BCR molecular density in individual clusters, leading to decreased BCR phosphorylation. Increased BCR molecular density reduced levels of the stimulatory kinase Syk, the inhibitory phosphatase SHIP-1, and their phosphorylated forms in individual BCR clusters. These results suggest that N-WASP-activated Arp2/3, coordinating with myosin, generates centripetally moving foci and contractile actomyosin ring-like structures from lamellipodial networks, enabling contraction. B-cell contraction attenuates BCR signaling by pushing out both stimulatory kinases and inhibitory phosphatases from BCR clusters, providing novel insights into actin-facilitated signal attenuation.
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Affiliation(s)
- Anshuman Bhanja
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Margaret K. Seeley-Fallen
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Michelle Lazzaro
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Arpita Upadhyaya
- Biophysics Program, University of Maryland, College Park, MD, 20742, USA
- Department of Physics, University of Maryland, College Park, MD, 20742, USA
- Institute for Physical Science and Technology, University of Maryland, College Park, MD, 20742, USA
| | - Wenxia Song
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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17
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Rappazzo CG, Fernández-Quintero ML, Mayer A, Wu NC, Greiff V, Guthmiller JJ. Defining and Studying B Cell Receptor and TCR Interactions. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 211:311-322. [PMID: 37459189 PMCID: PMC10495106 DOI: 10.4049/jimmunol.2300136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 04/15/2023] [Indexed: 07/20/2023]
Abstract
BCRs (Abs) and TCRs (or adaptive immune receptors [AIRs]) are the means by which the adaptive immune system recognizes foreign and self-antigens, playing an integral part in host defense, as well as the emergence of autoimmunity. Importantly, the interaction between AIRs and their cognate Ags defies a simple key-in-lock paradigm and is instead a complex many-to-many mapping between an individual's massively diverse AIR repertoire, and a similarly diverse antigenic space. Understanding how adaptive immunity balances specificity with epitopic coverage is a key challenge for the field, and terms such as broad specificity, cross-reactivity, and polyreactivity remain ill-defined and are used inconsistently. In this Immunology Notes and Resources article, a group of experimental, structural, and computational immunologists define commonly used terms associated with AIR binding, describe methodologies to study these binding modes, as well as highlight the implications of these different binding modes for therapeutic design.
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Affiliation(s)
| | | | - Andreas Mayer
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK
| | - Nicholas C. Wu
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Victor Greiff
- Department of Immunology, University of Oslo and Oslo University Hospital, 0372 Oslo, Norway
| | - Jenna J. Guthmiller
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
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18
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Rice MT, Gully BS. The clarifying lens of cryo-electron microscopy in immunoglobulin M biology. Immunol Cell Biol 2023; 101:584-586. [PMID: 37221908 DOI: 10.1111/imcb.12656] [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] [Indexed: 05/25/2023]
Abstract
In this article, we discuss recent advances into the structural analyses of immunoglobulin M complexes, which are enabling comprehensive characterization of these enigmatic antibodies, to reveal central tenets of immunoglobulin M immunobiology and inform their immunotherapeutic use.
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Affiliation(s)
- Michael T Rice
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Benjamin S Gully
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
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19
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Sutton BJ. Multi-faceted immunoglobulin M meets its elusive receptor. Nat Struct Mol Biol 2023:10.1038/s41594-023-01030-7. [PMID: 37433905 DOI: 10.1038/s41594-023-01030-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023]
Affiliation(s)
- Brian J Sutton
- Randall Centre for Cell & Molecular Biophysics, King's College London, London, UK.
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20
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Bhattacharyya P, Christopherson RI, Skarratt KK, Chen JZ, Balle T, Fuller SJ. Combination of High-Resolution Structures for the B Cell Receptor and Co-Receptors Provides an Understanding of Their Interactions with Therapeutic Antibodies. Cancers (Basel) 2023; 15:cancers15112881. [PMID: 37296844 DOI: 10.3390/cancers15112881] [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: 04/19/2023] [Revised: 05/19/2023] [Accepted: 05/19/2023] [Indexed: 06/12/2023] Open
Abstract
B cells are central to the adaptive immune response, providing long lasting immunity after infection. B cell activation is mediated by a cell surface B cell receptor (BCR) following recognition of an antigen. BCR signaling is modulated by several co-receptors including CD22 and a complex that contains CD19 and CD81. Aberrant signaling through the BCR and co-receptors promotes the pathogenesis of several B cell malignancies and autoimmune diseases. Treatment of these diseases has been revolutionized by the development of monoclonal antibodies that bind to B cell surface antigens, including the BCR and its co-receptors. However, malignant B cells can escape targeting by several mechanisms and until recently, rational design of antibodies has been limited by the lack of high-resolution structures of the BCR and its co-receptors. Herein we review recently determined cryo-electron microscopy (cryo-EM) and crystal structures of the BCR, CD22, CD19 and CD81 molecules. These structures provide further understanding of the mechanisms of current antibody therapies and provide scaffolds for development of engineered antibodies for treatment of B cell malignancies and autoimmune diseases.
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Affiliation(s)
- Puja Bhattacharyya
- Sydney Medical School Nepean, Faculty of Medicine and Health, The University of Sydney, Kingswood, NSW 2750, Australia
- Blacktown Hospital, Blacktown, NSW 2148, Australia
| | - Richard I Christopherson
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Kristen K Skarratt
- Sydney Medical School Nepean, Faculty of Medicine and Health, The University of Sydney, Kingswood, NSW 2750, Australia
- Nepean Hospital, Kingswood, NSW 2747, Australia
| | - Jake Z Chen
- Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
- Brain and Mind Centre, The University of Sydney, Camperdown, NSW 2050, Australia
| | - Thomas Balle
- Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
- Brain and Mind Centre, The University of Sydney, Camperdown, NSW 2050, Australia
| | - Stephen J Fuller
- Sydney Medical School Nepean, Faculty of Medicine and Health, The University of Sydney, Kingswood, NSW 2750, Australia
- Nepean Hospital, Kingswood, NSW 2747, Australia
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21
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Chen Q, Menon RP, Masino L, Tolar P, Rosenthal PB. Structural basis for Fc receptor recognition of immunoglobulin M. Nat Struct Mol Biol 2023:10.1038/s41594-023-00985-x. [PMID: 37095205 DOI: 10.1038/s41594-023-00985-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 03/31/2023] [Indexed: 04/26/2023]
Abstract
Immunoglobulin Fc receptors are cell surface transmembrane proteins that bind to the Fc constant region of antibodies and play critical roles in regulating immune responses by activation of immune cells, clearance of immune complexes and regulation of antibody production. FcμR is the immunoglobulin M (IgM) antibody isotype-specific Fc receptor involved in the survival and activation of B cells. Here we reveal eight binding sites for the human FcμR immunoglobulin domain on the IgM pentamer by cryogenic electron microscopy. One of the sites overlaps with the binding site for the polymeric immunoglobulin receptor (pIgR), but a different mode of FcμR binding explains its antibody isotype specificity. Variation in FcμR binding sites and their occupancy reflects the asymmetry of the IgM pentameric core and the versatility of FcμR binding. The complex explains engagement with polymeric serum IgM and the monomeric IgM B-cell receptor (BCR).
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Affiliation(s)
- Qu Chen
- Structural Biology Science Technology Platform, The Francis Crick Institute, London, UK
| | - Rajesh P Menon
- Immune Receptor Activation Laboratory, The Francis Crick Institute, London, UK
| | - Laura Masino
- Structural Biology Science Technology Platform, The Francis Crick Institute, London, UK
| | - Pavel Tolar
- Immune Receptor Activation Laboratory, The Francis Crick Institute, London, UK.
- Institute of Immunity and Transplantation, University College London, London, UK.
| | - Peter B Rosenthal
- Structural Biology of Cells and Viruses Laboratory, The Francis Crick Institute, London, UK.
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22
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Li Y, Shen H, Zhang R, Ji C, Wang Y, Su C, Xiao J. Immunoglobulin M perception by FcμR. Nature 2023; 615:907-912. [PMID: 36949194 DOI: 10.1038/s41586-023-05835-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 02/13/2023] [Indexed: 03/24/2023]
Abstract
Immunoglobulin M (IgM) is the first antibody to emerge during embryonic development and the humoral immune response1. IgM can exist in several distinct forms, including monomeric, membrane-bound IgM within the B cell receptor (BCR) complex, pentameric and hexameric IgM in serum and secretory IgM on the mucosal surface. FcμR, the only IgM-specific receptor in mammals, recognizes different forms of IgM to regulate diverse immune responses2-5. However, the underlying molecular mechanisms remain unknown. Here we delineate the structural basis of the FcμR-IgM interaction by crystallography and cryo-electron microscopy. We show that two FcμR molecules interact with a Fcμ-Cμ4 dimer, suggesting that FcμR can bind to membrane-bound IgM with a 2:1 stoichiometry. Further analyses reveal that FcμR-binding sites are accessible in the context of IgM BCR. By contrast, pentameric IgM can recruit four FcμR molecules to bind on the same side and thereby facilitate the formation of an FcμR oligomer. One of these FcμR molecules occupies the binding site of the secretory component. Nevertheless, four FcμR molecules bind to the other side of secretory component-containing secretory IgM, consistent with the function of FcμR in the retrotransport of secretory IgM. These results reveal intricate mechanisms of IgM perception by FcμR.
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Affiliation(s)
- Yaxin Li
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, P. R. China
| | - Hao Shen
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, P. R. China
| | - Ruixue Zhang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, P. R. China
| | - Chenggong Ji
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, P. R. China
| | - Yuxin Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, P. R. China
| | - Chen Su
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, P. R. China
| | - Junyu Xiao
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, P. R. China.
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, P. R. China.
- Changping Laboratory, Beijing, P. R. China.
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23
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Thomas C, Tampé R. Structure and mechanism of immunoreceptors: New horizons in T cell and B cell receptor biology and beyond. Curr Opin Struct Biol 2023; 80:102570. [PMID: 36940642 DOI: 10.1016/j.sbi.2023.102570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 01/15/2023] [Accepted: 02/07/2023] [Indexed: 03/23/2023]
Abstract
Immunoreceptors, also named non-catalytic tyrosine-phosphorylated receptors, are a large class of leukocyte cell-surface proteins critically involved in innate and adaptive immune responses. Their most characteristic defining feature is a shared signal transduction machinery where binding events of cell surface-anchored ligands to the small extracellular receptor domains are translated into phosphorylation of conserved tyrosine-containing cytosolic sequence motifs initiating downstream signal transduction cascades. Despite their central importance to immunology, the molecular mechanism of how ligand binding activates the receptors and results in robust intracellular signaling has remained enigmatic. Recent breakthroughs in our understanding of the architecture and triggering mechanism of immunoreceptors come from cryogenic electron microscopy studies of the B cell and T cell antigen receptors.
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Affiliation(s)
- Christoph Thomas
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt/Main, Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt/Main, Germany.
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24
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Zhu KF, Yuan C, Du YM, Sun KL, Zhang XK, Vogel H, Jia XD, Gao YZ, Zhang QF, Wang DP, Zhang HW. Applications and prospects of cryo-EM in drug discovery. Mil Med Res 2023; 10:10. [PMID: 36872349 PMCID: PMC9986049 DOI: 10.1186/s40779-023-00446-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 02/14/2023] [Indexed: 03/07/2023] Open
Abstract
Drug discovery is a crucial part of human healthcare and has dramatically benefited human lifespan and life quality in recent centuries, however, it is usually time- and effort-consuming. Structural biology has been demonstrated as a powerful tool to accelerate drug development. Among different techniques, cryo-electron microscopy (cryo-EM) is emerging as the mainstream of structure determination of biomacromolecules in the past decade and has received increasing attention from the pharmaceutical industry. Although cryo-EM still has limitations in resolution, speed and throughput, a growing number of innovative drugs are being developed with the help of cryo-EM. Here, we aim to provide an overview of how cryo-EM techniques are applied to facilitate drug discovery. The development and typical workflow of cryo-EM technique will be briefly introduced, followed by its specific applications in structure-based drug design, fragment-based drug discovery, proteolysis targeting chimeras, antibody drug development and drug repurposing. Besides cryo-EM, drug discovery innovation usually involves other state-of-the-art techniques such as artificial intelligence (AI), which is increasingly active in diverse areas. The combination of cryo-EM and AI provides an opportunity to minimize limitations of cryo-EM such as automation, throughput and interpretation of medium-resolution maps, and tends to be the new direction of future development of cryo-EM. The rapid development of cryo-EM will make it as an indispensable part of modern drug discovery.
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Affiliation(s)
- Kong-Fu Zhu
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, 518055 Guangdong China
| | - Chuang Yuan
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University, Beijing, 100191 China
| | - Yong-Ming Du
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105 USA
| | - Kai-Lei Sun
- Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Hong Kong, 999077 China
| | - Xiao-Kang Zhang
- Interdisciplinary Center for Brain Information, the Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055 Guangdong China
- Faculty of Life and Health Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055 Guangdong China
- Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055 Guangdong China
| | - Horst Vogel
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055 Guangdong China
| | - Xu-Dong Jia
- State Key Lab for Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275 China
| | - Yuan-Zhu Gao
- Cryo-EM Facility Center, Southern University of Science and Technology, Shenzhen, 518055 Guangdong China
| | - Qin-Fen Zhang
- State Key Lab for Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275 China
| | - Da-Ping Wang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, 518055 Guangdong China
- Department of Orthopedics, Shenzhen Intelligent Orthopaedics and Biomedical Innovation Platform, Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Shenzhen Second People’s Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, 518000 Guangdong China
| | - Hua-Wei Zhang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, 518055 Guangdong China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, 518055 Guangdong China
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25
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Crowley AR, Mehlenbacher MR, Sajadi MM, DeVico AL, Lewis GK, Ackerman ME. Evidence of variable human Fcγ receptor-Fc affinities across differentially-complexed IgG. MAbs 2023; 15:2231128. [PMID: 37405954 PMCID: PMC10324447 DOI: 10.1080/19420862.2023.2231128] [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: 12/12/2022] [Revised: 06/16/2023] [Accepted: 06/26/2023] [Indexed: 07/07/2023] Open
Abstract
Antibody-mediated effector functions are widely considered to unfold according to an associative model of IgG-Fcγ receptor (FcγR) interactions. The associative model presupposes that Fc receptors cannot discriminate antigen-bound IgG from free IgG in solution and have equivalent affinities for each. Therefore, the clustering of Fcγ receptors (FcγR) in the cell membrane, cross-activation of intracellular signaling domains, and the formation of the immune synapse are all the result of avid interactions between the Fc region of IgG and FcγRs that collectively overcome the individually weak, transient interactions between binding partners. Antibody allostery, specifically conformational allostery, is a competing model in which antigen-bound antibody molecules undergo a physical rearrangement that causes them to stand out from the background of free IgG by virtue of greater FcγR affinity. Various evidence exists in support of this model of antibody allostery, but it remains controversial. We report observations from multiplexed, label-free kinetic experiments in which the affinity values of FcγR were characterized for covalently immobilized, captured, and antigen-bound IgG. Across the strategies tested, receptors had greater affinity for the antigen-bound mode of IgG presentation. This phenomenon was observed across multiple FcγRs and generalized to multiple antigens, antibody specificities, and subclasses. Furthermore, the thermodynamic signatures of FcγR binding to free or immune-complexed IgG in solution differed when measured by an orthogonal label-free method, but the failure to recapitulate the trend in overall affinity leaves open questions as to what additional factors may be at play.
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Affiliation(s)
- Andrew R. Crowley
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Dartmouth College, Hanover, NH, USA
| | | | - Mohammad M. Sajadi
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, USA
- Baltimore VA Medical Center, VA Maryland Health Care System, Baltimore, USA
| | - Anthony L. DeVico
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, USA
| | - George K. Lewis
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, USA
| | - Margaret E. Ackerman
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Dartmouth College, Hanover, NH, USA
- Department of Chemistry, Dartmouth College, Hanover, NH, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
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26
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Han F, Chen Y, Zhu Y, Huang Z. Antigen receptor structure and signaling. Adv Immunol 2023; 157:1-28. [PMID: 37061286 DOI: 10.1016/bs.ai.2023.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2023]
Abstract
The key to mounting an immune response is that the host cells must be coordinated to generate an appropriate immune response against the pathogenic invaders. Antigen receptors recognize specific molecular structures and recruit adaptors through their effector domains, triggering trans-membrane transduction signaling pathway to exert immune response. The T cell antigen receptor (TCR) and B cell antigen receptor (BCR) are the primary determinant of immune responses to antigens. Their structure determines the mode of signaling and signal transduction determines cell fate, leading to changes at the molecular and cellular level. Studies of antigen receptor structure and signaling revealed the basis of immune response triggering, providing clues to antigen receptor priming and a foundation for the rational design of immunotherapies. In recent years, the increased research on the structure of antigen receptors has greatly contributed to the understanding of immune response, different immune-related diseases and even tumors. In this review, we describe in detail the current view and advances of the antigen structure and signaling.
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Affiliation(s)
- Fang Han
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Yan Chen
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Yuwei Zhu
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Zhiwei Huang
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin, China.
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27
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Dong Y, Pi X, Bartels-Burgahn F, Saltukoglu D, Liang Z, Yang J, Alt FW, Reth M, Wu H. Structural principles of B cell antigen receptor assembly. Nature 2022; 612:156-161. [PMID: 36228656 PMCID: PMC10499536 DOI: 10.1038/s41586-022-05412-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 10/05/2022] [Indexed: 12/15/2022]
Abstract
The B cell antigen receptor (BCR) is composed of a membrane-bound class M, D, G, E or A immunoglobulin for antigen recognition1-3 and a disulfide-linked Igα (also known as CD79A) and Igβ (also known as CD79B) heterodimer (Igα/β) that functions as the signalling entity through intracellular immunoreceptor tyrosine-based activation motifs (ITAMs)4,5. The organizing principle of the BCR remains unknown. Here we report cryo-electron microscopy structures of mouse full-length IgM BCR and its Fab-deleted form. At the ectodomain (ECD), the Igα/β heterodimer mainly uses Igα to associate with Cµ3 and Cµ4 domains of one heavy chain (µHC) while leaving the other heavy chain (µHC') unbound. The transmembrane domain (TMD) helices of µHC and µHC' interact with those of the Igα/β heterodimer to form a tight four-helix bundle. The asymmetry at the TMD prevents the recruitment of two Igα/β heterodimers. Notably, the connecting peptide between the ECD and TMD of µHC intervenes in between those of Igα and Igβ to guide TMD assembly through charge complementarity. Weaker but distinct density for the Igβ ITAM nestles next to the TMD, suggesting potential autoinhibition of ITAM phosphorylation. Interfacial analyses suggest that all BCR classes utilize a general organizational architecture. Our studies provide a structural platform for understanding B cell signalling and designing rational therapies against BCR-mediated diseases.
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Affiliation(s)
- Ying Dong
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Xiong Pi
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Frauke Bartels-Burgahn
- Signaling Research Centers BIOSS and CIBSS, Freiburg, Germany
- Department of Molecular Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Deniz Saltukoglu
- Signaling Research Centers BIOSS and CIBSS, Freiburg, Germany
- Department of Molecular Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Zhuoyi Liang
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- HHMI, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Jianying Yang
- Signaling Research Centers BIOSS and CIBSS, Freiburg, Germany
- Department of Molecular Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Frederick W Alt
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- HHMI, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Michael Reth
- Signaling Research Centers BIOSS and CIBSS, Freiburg, Germany.
- Department of Molecular Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany.
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.
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28
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Chen Q, Menon R, Calder LJ, Tolar P, Rosenthal PB. Cryomicroscopy reveals the structural basis for a flexible hinge motion in the immunoglobulin M pentamer. Nat Commun 2022; 13:6314. [PMID: 36274064 PMCID: PMC9588798 DOI: 10.1038/s41467-022-34090-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 10/12/2022] [Indexed: 12/25/2022] Open
Abstract
Immunoglobulin M (IgM) is the most ancient of the five isotypes of immunoglobulin (Ig) molecules and serves as the first line of defence against pathogens. Here, we use cryo-EM to image the structure of the human full-length IgM pentamer, revealing antigen binding domains flexibly attached to the asymmetric and rigid core formed by the Cμ4 and Cμ3 constant regions and the J-chain. A hinge is located at the Cμ3/Cμ2 domain interface, allowing Fabs and Cμ2 to pivot as a unit both in-plane and out-of-plane. This motion is different from that observed in IgG and IgA, where the two Fab arms are able to swing independently. A biased orientation of one pair of Fab arms results from asymmetry in the constant domain (Cμ3) at the IgM subunit interacting most extensively with the J-chain. This may influence the multi-valent binding to surface-associated antigens and complement pathway activation. By comparison, the structure of the Fc fragment in the IgM monomer is similar to that of the pentamer, but is more dynamic in the Cμ4 domain.
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Affiliation(s)
- Qu Chen
- grid.451388.30000 0004 1795 1830Structural Biology Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT UK
| | - Rajesh Menon
- grid.451388.30000 0004 1795 1830Immune Receptor Activation Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT UK
| | - Lesley J. Calder
- grid.451388.30000 0004 1795 1830Structural Biology of Cells and Viruses Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT UK
| | - Pavel Tolar
- Immune Receptor Activation Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK. .,Institute of Immunity and Transplantation, University College London, Rowland Hill Street, London, NW3 2PP, UK.
| | - Peter B. Rosenthal
- grid.451388.30000 0004 1795 1830Structural Biology of Cells and Viruses Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT UK
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