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Musunuri S, Weidenbacher PAB, Kim PS. Bringing immunofocusing into focus. NPJ Vaccines 2024; 9:11. [PMID: 38195562 PMCID: PMC10776678 DOI: 10.1038/s41541-023-00792-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 12/07/2023] [Indexed: 01/11/2024] Open
Abstract
Immunofocusing is a strategy to create immunogens that redirect humoral immune responses towards a targeted epitope and away from non-desirable epitopes. Immunofocusing methods often aim to develop "universal" vaccines that provide broad protection against highly variant viruses such as influenza virus, human immunodeficiency virus (HIV-1), and most recently, severe acute respiratory syndrome coronavirus (SARS-CoV-2). We use existing examples to illustrate five main immunofocusing strategies-cross-strain boosting, mosaic display, protein dissection, epitope scaffolding, and epitope masking. We also discuss obstacles for immunofocusing like immune imprinting. A thorough understanding, advancement, and application of the methods we outline here will enable the design of high-resolution vaccines that protect against future viral outbreaks.
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Affiliation(s)
- Sriharshita Musunuri
- Stanford ChEM-H, Stanford University, Stanford, CA, 94305, USA
- Department of Biochemistry, Stanford University, Stanford, CA, 94305, USA
| | - Payton A B Weidenbacher
- Stanford ChEM-H, Stanford University, Stanford, CA, 94305, USA
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Peter S Kim
- Stanford ChEM-H, Stanford University, Stanford, CA, 94305, USA.
- Department of Biochemistry, Stanford University, Stanford, CA, 94305, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA.
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2
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Bruno A, Scrima M, Novellino E, D'Errico G, D'Ursi AM, Limongelli V. The glycan role in the glycopeptide immunogenicity revealed by atomistic simulations and spectroscopic experiments on the multiple sclerosis biomarker CSF114(Glc). Sci Rep 2015; 5:9200. [PMID: 25776265 PMCID: PMC4361856 DOI: 10.1038/srep09200] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/24/2015] [Indexed: 12/22/2022] Open
Abstract
Glycoproteins are often recognized as not-self molecules by antibodies triggering the onset of severe autoimmune diseases such as Multiple Sclerosis (MS). Thus, the development of antigen-mimicking biomarkers represents an attractive strategy for an early diagnosis of the disease. An example is the synthetic glycopeptide CSF114(Glc), which was designed and tested as MS biomarker and whose clinical application was limited by its reduced ability to detect autoantibodies in MS patients. In the attempt to improve the efficacy of CSF114(Glc), we have characterized all the events leading to the final binding of the biomarker to the autoantibody using atomistic simulations, ESR and NMR experiments. The glycosydic moiety plays a primary role in the whole process. In particular, in an environment mimicking that used in the clinical tests the glycopeptide assumes a α-helix structure that is functional for the interaction with the antibody. In this conformation CSF114(Glc) binds the monoclonal antibody mAb8-18C5 similarly to the myelin oligodendrocyte glycoprotein MOG, which is a known MS auto-antigen, thus explaining its diagnostic activity. Our study offers new molecular bases to design more effective biomarkers and provides a most valid protocol to investigate other systems where the environment effect is determinant for the biological activity.
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Affiliation(s)
- Agostino Bruno
- Department of Pharmacy, University of Naples "Federico II", via D. Montesano 49, I-80131 Naples, Italy
| | - Mario Scrima
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano, Italy
| | - Ettore Novellino
- Department of Pharmacy, University of Naples "Federico II", via D. Montesano 49, I-80131 Naples, Italy
| | - Gerardino D'Errico
- Dipartimento di Scienze Chimiche, Università di Napoli "Federico II", Complesso di Monte Sant'Angelo, via Cinthia, 80126 Naples, Italy
| | - Anna Maria D'Ursi
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano, Italy
| | - Vittorio Limongelli
- 1] Department of Pharmacy, University of Naples "Federico II", via D. Montesano 49, I-80131 Naples, Italy [2] Università della Svizzera Italiana (USI), Faculty of Informatics, Institute of Computational Science, via G. Buffi 13, CH-6900 Lugano, Switzerland
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3
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Apellániz B, Nieva JL. The Use of Liposomes to Shape Epitope Structure and Modulate Immunogenic Responses of Peptide Vaccines Against HIV MPER. PEPTIDE AND PROTEIN VACCINES 2015; 99:15-54. [DOI: 10.1016/bs.apcsb.2015.03.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Kim AS, Leaman DP, Zwick MB. Antibody to gp41 MPER alters functional properties of HIV-1 Env without complete neutralization. PLoS Pathog 2014; 10:e1004271. [PMID: 25058619 PMCID: PMC4110039 DOI: 10.1371/journal.ppat.1004271] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 06/11/2014] [Indexed: 01/08/2023] Open
Abstract
Human antibody 10E8 targets the conserved membrane proximal external region (MPER) of envelope glycoprotein (Env) subunit gp41 and neutralizes HIV-1 with exceptional potency. Remarkably, HIV-1 containing mutations that reportedly knockout 10E8 binding to linear MPER peptides are partially neutralized by 10E8, producing a local plateau in the dose response curve. Here, we found that virus partially neutralized by 10E8 becomes significantly less neutralization sensitive to various MPER antibodies and to soluble CD4 while becoming significantly more sensitive to antibodies and fusion inhibitors against the heptad repeats of gp41. Thus, 10E8 modulates sensitivity of Env to ligands both pre- and post-receptor engagement without complete neutralization. Partial neutralization by 10E8 was influenced at least in part by perturbing Env glycosylation. With unliganded Env, 10E8 bound with lower apparent affinity and lower subunit occupancy to MPER mutant compared to wild type trimers. However, 10E8 decreased functional stability of wild type Env while it had an opposite, stabilizing effect on MPER mutant Envs. Clade C isolates with natural MPER polymorphisms also showed partial neutralization by 10E8 with altered sensitivity to various gp41-targeted ligands. Our findings suggest a novel mechanism of virus neutralization by demonstrating how antibody binding to the base of a trimeric spike cross talks with adjacent subunits to modulate Env structure and function. The ability of an antibody to stabilize, destabilize, partially neutralize as well as alter neutralization sensitivity of a virion spike pre- and post-receptor engagement may have implications for immunotherapy and vaccine design.
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Affiliation(s)
- Arthur S. Kim
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Daniel P. Leaman
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Michael B. Zwick
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
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Co-expression of foreign proteins tethered to HIV-1 envelope glycoprotein on the cell surface by introducing an intervening second membrane-spanning domain. PLoS One 2014; 9:e96790. [PMID: 24804933 PMCID: PMC4013048 DOI: 10.1371/journal.pone.0096790] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 04/11/2014] [Indexed: 11/19/2022] Open
Abstract
The envelope glycoprotein (Env) of human immunodeficiency virus type I (HIV-1) mediates membrane fusion. To analyze the mechanism of HIV-1 Env-mediated membrane fusion, it is desirable to determine the expression level of Env on the cell surface. However, the quantification of Env by immunological staining is often hampered by the diversity of HIV-1 Env and limited availability of universal antibodies that recognize different Envs with equal efficiency. To overcome this problem, here we linked a tag protein called HaloTag at the C-terminus of HIV-1 Env. To relocate HaloTag to the cell surface, we introduced a second membrane-spanning domain (MSD) between Env and HaloTag. The MSD of transmembrane protease serine 11D, a type II transmembrane protein, successfully relocated HaloTag to the cell surface. The surface level of Env can be estimated indirectly by staining HaloTag with a specific membrane-impermeable fluorescent ligand. This tagging did not compromise the fusogenicity of Env drastically. Furthermore, fusogenicity of Env was preserved even after the labeling with the ligands. We have also found that an additional foreign peptide or protein such as C34 or neutralizing single-chain variable fragment (scFv) can be linked to the C-terminus of the HaloTag protein. Using these constructs, we were able to determine the required length of C34 and critical residues of neutralizing scFv for blocking membrane fusion, respectively.
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Peptide entry inhibitors of enveloped viruses: the importance of interfacial hydrophobicity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2180-97. [PMID: 24780375 PMCID: PMC7094693 DOI: 10.1016/j.bbamem.2014.04.015] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 04/08/2014] [Accepted: 04/17/2014] [Indexed: 12/16/2022]
Abstract
There are many peptides known that inhibit the entry of enveloped viruses into cells, including one peptide that is successfully being used in the clinic as a drug. In this review, we discuss the discovery, antiviral activity and mechanism of action of such peptides. While peptide entry inhibitors have been discovered by a wide variety of approaches (structure-based, accidental, intentional, rational and brute force) we show here that they share a common physical chemical property: they are at least somewhat hydrophobic and/or amphipathic and have a propensity to interact with membrane interfaces. We propose that this propensity drives a shared mechanism of action for many peptide entry inhibitors, involving direct interactions with viral and cellular membranes, as well as interactions with the complex hydrophobic protein/lipid interfaces that are exposed, at least transiently, during virus-cell fusion. By interacting simultaneously with the membrane interfaces and other critical hydrophobic surfaces, we hypothesize that peptide entry inhibitors can act by changing the physical chemistry of the membranes, and the fusion protein interfaces bridging them, and by doing so interfere with the fusion of cellular and viral membranes. Based on this idea, we propose that an approach that focuses on the interfacial hydrophobicity of putative entry inhibitors could lead to the efficient discovery of novel, broad-spectrum viral entry inhibitors. This article is part of a Special Issue entitled: Interfacially Active Peptides and Proteins. Guest Editors: William C. Wimley and Kalina Hristova.
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Apellániz B, Huarte N, Largo E, Nieva JL. The three lives of viral fusion peptides. Chem Phys Lipids 2014; 181:40-55. [PMID: 24704587 PMCID: PMC4061400 DOI: 10.1016/j.chemphyslip.2014.03.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 03/19/2014] [Accepted: 03/20/2014] [Indexed: 02/07/2023]
Abstract
The presence of a fusion peptide (FP) is a hallmark of viral fusion glycoproteins. Structure–function relationships underlying FP conservation remain greatly unknown. FPs establish interactions satisfying their folding within pre-fusion glycoproteins. Upon fusion activation FPs insert into and restructure target membranes. FPs can finally combine with transmembrane domains to form integral membrane bundles.
Fusion peptides comprise conserved hydrophobic domains absolutely required for the fusogenic activity of glycoproteins from divergent virus families. After 30 years of intensive research efforts, the structures and functions underlying their high degree of sequence conservation are not fully elucidated. The long-hydrophobic viral fusion peptide (VFP) sequences are structurally constrained to access three successive states after biogenesis. Firstly, the VFP sequence must fulfill the set of native interactions required for (meta) stable folding within the globular ectodomains of glycoprotein complexes. Secondly, at the onset of the fusion process, they get transferred into the target cell membrane and adopt specific conformations therein. According to commonly accepted mechanistic models, membrane-bound states of the VFP might promote the lipid bilayer remodeling required for virus-cell membrane merger. Finally, at least in some instances, several VFPs co-assemble with transmembrane anchors into membrane integral helical bundles, following a locking movement hypothetically coupled to fusion-pore expansion. Here we review different aspects of the three major states of the VFPs, including the functional assistance by other membrane-transferring glycoprotein regions, and discuss briefly their potential as targets for clinical intervention.
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Affiliation(s)
- Beatriz Apellániz
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - Nerea Huarte
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - Eneko Largo
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - José L Nieva
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain.
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Serrano S, Araujo A, Apellániz B, Bryson S, Carravilla P, de la Arada I, Huarte N, Rujas E, Pai EF, Arrondo JLR, Domene C, Jiménez MA, Nieva JL. Structure and immunogenicity of a peptide vaccine, including the complete HIV-1 gp41 2F5 epitope: implications for antibody recognition mechanism and immunogen design. J Biol Chem 2014; 289:6565-6580. [PMID: 24429284 DOI: 10.1074/jbc.m113.527747] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The membrane-proximal external region (MPER) of gp41 harbors the epitope recognized by the broadly neutralizing anti-HIV 2F5 antibody, a research focus in HIV-1 vaccine development. In this work, we analyze the structure and immunogenic properties of MPERp, a peptide vaccine that includes the following: (i) the complete sequence protected from proteolysis by the 2F5 paratope; (ii) downstream residues postulated to establish weak contacts with the CDR-H3 loop of the antibody, which are believed to be crucial for neutralization; and (iii) an aromatic rich anchor to the membrane interface. MPERp structures solved in dodecylphosphocholine micelles and 25% 1,1,1,3,3,3-hexafluoro-2-propanol (v/v) confirmed folding of the complete 2F5 epitope within continuous kinked helices. Infrared spectroscopy (IR) measurements demonstrated the retention of main helical conformations in immunogenic formulations based on alum, Freund's adjuvant, or two different types of liposomes. Binding to membrane-inserted MPERp, IR, molecular dynamics simulations, and characterization of the immune responses further suggested that packed helical bundles partially inserted into the lipid bilayer, rather than monomeric helices adsorbed to the membrane interface, could encompass effective MPER peptide vaccines. Together, our data constitute a proof-of-concept to support MPER-based peptides in combination with liposomes as stand-alone immunogens and suggest new approaches for structure-aided MPER vaccine development.
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Affiliation(s)
- Soraya Serrano
- Institute of Physical Chemistry "Rocasolano," Consejo Superior de Investigaciones Científicas (IQFR-CSIC), Serrano 119, E-28006 Madrid, Spain
| | - Aitziber Araujo
- Biophysics Unit, Consejo Superior de Investigaciones Científicas and University of the Basque Country (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P. O. Box 644, 48080 Bilbao, Spain
| | - Beatriz Apellániz
- Biophysics Unit, Consejo Superior de Investigaciones Científicas and University of the Basque Country (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P. O. Box 644, 48080 Bilbao, Spain
| | - Steve Bryson
- Departments of Biochemistry, Medical Biophysics, and Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada; The Campbell Family Institute for Cancer Research, Ontario Cancer Institute/University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Pablo Carravilla
- Biophysics Unit, Consejo Superior de Investigaciones Científicas and University of the Basque Country (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P. O. Box 644, 48080 Bilbao, Spain
| | - Igor de la Arada
- Biophysics Unit, Consejo Superior de Investigaciones Científicas and University of the Basque Country (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P. O. Box 644, 48080 Bilbao, Spain
| | - Nerea Huarte
- Biophysics Unit, Consejo Superior de Investigaciones Científicas and University of the Basque Country (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P. O. Box 644, 48080 Bilbao, Spain
| | - Edurne Rujas
- Biophysics Unit, Consejo Superior de Investigaciones Científicas and University of the Basque Country (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P. O. Box 644, 48080 Bilbao, Spain
| | - Emil F Pai
- Departments of Biochemistry, Medical Biophysics, and Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada; The Campbell Family Institute for Cancer Research, Ontario Cancer Institute/University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - José L R Arrondo
- Biophysics Unit, Consejo Superior de Investigaciones Científicas and University of the Basque Country (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P. O. Box 644, 48080 Bilbao, Spain
| | - Carmen Domene
- Chemistry Research Laboratory, Mansfield Road, University of Oxford, Oxford OX1 3TA, United Kingdom; Department of Chemistry, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom
| | - María Angeles Jiménez
- Institute of Physical Chemistry "Rocasolano," Consejo Superior de Investigaciones Científicas (IQFR-CSIC), Serrano 119, E-28006 Madrid, Spain.
| | - José L Nieva
- Biophysics Unit, Consejo Superior de Investigaciones Científicas and University of the Basque Country (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P. O. Box 644, 48080 Bilbao, Spain.
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Crespillo S, Casares S, Mateo PL, Conejero-Lara F. Thermodynamic analysis of the binding of 2F5 (Fab and immunoglobulin G forms) to its gp41 epitope reveals a strong influence of the immunoglobulin Fc region on affinity. J Biol Chem 2013; 289:594-9. [PMID: 24302742 DOI: 10.1074/jbc.c113.524439] [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] [Indexed: 12/26/2022] Open
Abstract
Immunotherapies and vaccines based on the induction of broadly neutralizing monoclonal antibodies (bNAbs) have become outstanding strategies against HIV-1. Diverse bNAbs recognizing different regions of the HIV-1 envelope have been identified and extensively studied. However, there is little information about the thermodynamics of binding of these bNAbs and their epitopes. We used isothermal titration calorimetry to characterize thermodynamically the interactions between bNAb2F5 (in both the IgG and Fab forms) and its functional and core epitope peptides. We found that these interactions are enthalpically driven and opposed by a negative entropy change. The highest affinity was found for 2F5 IgG for its functional epitope, indicating that additional interactions involving residues flanking the core epitope contribute strongly to higher affinity. In addition, the strong influence of the Fc region on the binding affinity suggests long-range allosteric effects within IgG. Our results provide useful information for developing new therapeutics against HIV-1 and, in a broader scope, contribute to a better understanding of antigen-antibody recognition.
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Affiliation(s)
- Sara Crespillo
- From the Departamento de Química Física e Instituto de Biotecnología, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
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