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Parajuli B, Acharya K, Bach HC, Zhang S, Abrams CF, Chaiken I. Monovalent Lectin Microvirin Utilizes Hydropathic Recognition of HIV-1 Env for Inhibition of Virus Cell Infection. Viruses 2025; 17:82. [PMID: 39861871 PMCID: PMC11768445 DOI: 10.3390/v17010082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2024] [Revised: 01/03/2025] [Accepted: 01/06/2025] [Indexed: 01/30/2025] Open
Abstract
Microvirin is a lectin molecule known to have monovalent interaction with glycoprotein gp120. A previously reported high-resolution structural analysis defines the mannobiose-binding cavity of Microvirin. Nonetheless, structure does not directly define the energetics of binding contributions of protein contact residues. To better understand the nature of the MVN-Env glycan interaction, we used mutagenesis to evaluate the residue contributions to the mannobiose binding site of MVN that are important for Env gp120 glycan binding. MVN binding site amino acid residues were individually replaced by alanine, and the resulting purified recombinant MVN variants were examined for gp120 interaction using competition Enzyme-Linked Immunosorbent Assay (ELISA), biosensor surface plasmon resonance, calorimetry, and virus neutralization assays. Our findings highlight the role of both uncharged polar and non-polar residues in forming a hydropathic recognition site for the monovalent glycan engagement of Microvirin, in marked contrast to the charged residues utilized in the two Cyanovirin-N (CVN) glycan-binding sites.
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Affiliation(s)
- Bibek Parajuli
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA; (K.A.); (H.C.B.); (S.Z.)
| | - Kriti Acharya
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA; (K.A.); (H.C.B.); (S.Z.)
| | - Harry Charles Bach
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA; (K.A.); (H.C.B.); (S.Z.)
| | - Shiyu Zhang
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA; (K.A.); (H.C.B.); (S.Z.)
| | - Cameron F. Abrams
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, PA 19104, USA;
| | - Irwin Chaiken
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA; (K.A.); (H.C.B.); (S.Z.)
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2
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Gupta A, Yadav K, Yadav A, Ahmad R, Srivastava A, Kumar D, Khan MA, Dwivedi UN. Mannose-specific plant and microbial lectins as antiviral agents: A review. Glycoconj J 2024; 41:1-33. [PMID: 38244136 DOI: 10.1007/s10719-023-10142-7] [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: 09/02/2023] [Revised: 10/19/2023] [Accepted: 12/06/2023] [Indexed: 01/22/2024]
Abstract
Lectins are non-immunological carbohydrate-binding proteins classified on the basis of their structure, origin, and sugar specificity. The binding specificity of such proteins with the surface glycan moiety determines their activity and clinical applications. Thus, lectins hold great potential as diagnostic and drug discovery agents and as novel biopharmaceutical products. In recent years, significant advancements have been made in understanding plant and microbial lectins as therapeutic agents against various viral diseases. Among them, mannose-specific lectins have being proven as promising antiviral agents against a variety of viruses, such as HIV, Influenza, Herpes, Ebola, Hepatitis, Severe Acute Respiratory Syndrome Coronavirus-1 (SARS-CoV-1), Middle Eastern Respiratory Syndrome Coronavirus (MERS-CoV) and most recent Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). The binding of mannose-binding lectins (MBLs) from plants and microbes to high-mannose containing N-glycans (which may be simple or complex) of glycoproteins found on the surface of viruses has been found to be highly specific and mainly responsible for their antiviral activity. MBLs target various steps in the viral life cycle, including viral attachment, entry and replication. The present review discusses the brief classification and structure of lectins along with antiviral activity of various mannose-specific lectins from plants and microbial sources and their diagnostic and therapeutic applications against viral diseases.
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Affiliation(s)
- Ankita Gupta
- Department of Biochemistry, University of Lucknow, Lucknow, Uttar Pradesh, India
| | - Kusum Yadav
- Department of Biochemistry, University of Lucknow, Lucknow, Uttar Pradesh, India.
| | - Anurag Yadav
- Department of Microbiology, C.P. College of Agriculture, Sardarkrushinagar Dantiwada Agriculture University, District-Banaskantha, Gujarat, India
| | - Rumana Ahmad
- Department of Biochemistry, Era's Lucknow Medical College and Hospital, Era University, Lucknow, Uttar Pradesh, India.
| | - Aditi Srivastava
- Department of Biochemistry, Era's Lucknow Medical College and Hospital, Era University, Lucknow, Uttar Pradesh, India
| | - Dileep Kumar
- Department of Biochemistry, University of Lucknow, Lucknow, Uttar Pradesh, India
- Department of Biotechnology, Khwaja Moinuddin Chishti Language University, Lucknow, Uttar Pradesh, India
| | - Mohammad Amir Khan
- Department of Biochemistry, Era's Lucknow Medical College and Hospital, Era University, Lucknow, Uttar Pradesh, India
| | - U N Dwivedi
- Department of Biochemistry, University of Lucknow, Lucknow, Uttar Pradesh, India
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3
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Damm D, Kostka K, Weingärtner C, Wagner JT, Rojas-Sánchez L, Gensberger-Reigl S, Sokolova V, Überla K, Epple M, Temchura V. Covalent coupling of HIV-1 glycoprotein trimers to biodegradable calcium phosphate nanoparticles via genetically encoded aldehyde-tags. Acta Biomater 2022; 140:586-600. [PMID: 34968725 DOI: 10.1016/j.actbio.2021.12.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 12/14/2021] [Accepted: 12/20/2021] [Indexed: 01/02/2023]
Abstract
The usage of antigen-functionalized nanoparticles has become a major focus in the field of experimental HIV-1 vaccine research during the last decade. Various molecular mechanisms to couple native-like trimers of the HIV-1 envelope protein (Env) onto nanoparticle surfaces have been reported, but many come with disadvantages regarding the coupling efficiency and stability. In this study, a short amino acid sequence ("aldehyde-tag") was introduced at the C-terminus of a conformationally stabilized native-like Env. The post-translational conversion of a tag-associated cysteine to formylglycine creates a site-specific aldehyde group without alteration of the Env antigenicity. This aldehyde group was further utilized for bioconjugation of Env trimers. We demonstrated that the low acidic environment necessary for this bioconjugation is not affecting the trimer conformation. Furthermore, we developed a two-step coupling method for pH-sensitive nanoparticles. To this end, we conjugated aldehyde-tagged Env with Propargyl-PEG3-aminooxy linker (oxime ligation; Step-one) and coupled these conjugates by copper-catalyzed azide-alkyne cycloaddition (Click reaction; Step-two) to calcium phosphate nanoparticles (CaPs) functionalized with terminal azide groups. CaPs displaying orthogonally arranged Env trimers on their surface (o-CaPs) were superior in activation of Env-specific B-cells (in vitro) and induction of Env-specific antibody responses (in vivo) compared to CaPs with Env trimers coupled in a randomly oriented manner. Taken together, we present a reliable method for the site-specific, covalent coupling of HIV-1 Env native-like trimers to the surface of nanoparticle delivery systems. This method can be broadly applied for functionalization of nanoparticle platforms with conformationally stabilized candidate antigens for both vaccination and diagnostic approaches. STATEMENT OF SIGNIFICANCE: During the last decade antigen-functionalized nanoparticles have become a major focus in the field of experimental HIV-1 vaccines. Rational design led to the production of conformationally stabilized HIV-1 envelope protein (Env) trimers - the only target for the humoral immune system. Various molecular mechanisms to couple Env trimers onto nanoparticle surfaces have been reported, but many come with disadvantages regarding the coupling efficiency and stability. In this paper, we describe a highly selective bio-conjugation of Env trimers to the surface of medically relevant calcium phosphate nanoparticles. This method maintains the native-like protein conformation and has a broad potential application in functionalization of nanoparticle platforms with stabilized candidate antigens (including stabilized spike proteins of coronaviruses) for both vaccination and diagnostic approaches.
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Affiliation(s)
- D Damm
- Institute of Clinical and Molecular Virology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Schlossgarten 4, 91054 Erlangen, Germany
| | - K Kostka
- Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitätsstraße 5-7, 45141 Essen, Germany
| | - C Weingärtner
- Institute of Clinical and Molecular Virology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Schlossgarten 4, 91054 Erlangen, Germany
| | - J T Wagner
- Institute of Clinical and Molecular Virology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Schlossgarten 4, 91054 Erlangen, Germany
| | - L Rojas-Sánchez
- Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitätsstraße 5-7, 45141 Essen, Germany
| | - S Gensberger-Reigl
- Department of Chemistry and Pharmacy, Friedrich-Alexander University Erlangen-Nuremberg, Nikolaus-Fiebiger-Str. 10, 91058 Erlangen, Germany
| | - V Sokolova
- Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitätsstraße 5-7, 45141 Essen, Germany
| | - K Überla
- Institute of Clinical and Molecular Virology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Schlossgarten 4, 91054 Erlangen, Germany
| | - M Epple
- Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitätsstraße 5-7, 45141 Essen, Germany
| | - V Temchura
- Institute of Clinical and Molecular Virology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Schlossgarten 4, 91054 Erlangen, Germany.
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Zhao J, Song E, Huang Y, Yu A, Mechref Y. Variability in the Glycosylation Patterns of gp120 Proteins from Different Human Immunodeficiency Virus Type 1 Isolates Expressed in Different Host Cells. J Proteome Res 2021; 20:4862-4874. [PMID: 34448591 DOI: 10.1021/acs.jproteome.1c00587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The mature HIV-1 envelope (Env) glycoprotein is composed of gp120, the exterior subunit, and gp41, the transmembrane subunit assembled as trimer by noncovalent interaction. There is a great body of literature to prove that gp120 binds to CD4 first, then to the coreceptor. Binding experiments and functional assays have demonstrated that CD4 binding induces conformational changes in gp120 that enable or enhance its interaction with a coreceptor. Previous studies provided different glycomic maps for the HIV-1 gp120. Here, we build on previous work to report that the use of LC-MS/MS, in conjunction with hydrophilic interaction liquid chromatography (HILIC) enrichment to glycosylation sites, associated with the assorted neutralizing or binding events of glycosylation targeted antibodies from different clades or strains. In this study, the microheterogeneity of the glycosylation from 4 different clades of gp120s is deeply investigated. Aberrant glycosylation patterns were detected on gp120 that originated from different clades, viral sequences, and host cells. The results of this study may help provide a better understanding of the mechanism of how the glycans participate in the antibody neutralizing process that targets glycosylation sites.
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Affiliation(s)
- Jingfu Zhao
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Ehwang Song
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Yifan Huang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Aiying Yu
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Yehia Mechref
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
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Fadda E. Understanding the Structure and Function of Viral Glycosylation by Molecular Simulations: State-of-the-Art and Recent Case Studies. COMPREHENSIVE GLYCOSCIENCE 2021. [PMCID: PMC7834635 DOI: 10.1016/b978-0-12-819475-1.00056-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Parajuli B, Acharya K, Nangarlia A, Zhang S, Parajuli B, Dick A, Ngo B, Abrams CF, Chaiken I. Identification of a glycan cluster in gp120 essential for irreversible HIV-1 lytic inactivation by a lectin-based recombinantly engineered protein conjugate. Biochem J 2020; 477:4263-4280. [PMID: 33057580 DOI: 10.1042/bcj20200495] [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: 06/23/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 11/17/2022]
Abstract
We previously discovered a class of recombinant lectin conjugates, denoted lectin DLIs ('dual-acting lytic inhibitors') that bind to the HIV-1 envelope (Env) protein trimer and cause both lytic inactivation of HIV-1 virions and cytotoxicity of Env-expressing cells. To facilitate mechanistic investigation of DLI function, we derived the simplified prototype microvirin (MVN)-DLI, containing an MVN domain that binds high-mannose glycans in Env, connected to a DKWASLWNW sequence (denoted 'Trp3') derived from the membrane-associated region of gp41. The relatively much stronger affinity of the lectin component than Trp3 argues that the lectin functions to capture Env to enable Trp3 engagement and consequent Env membrane disruption and virolysis. The relatively simplified engagement pattern of MVN with Env opened up the opportunity, pursued here, to use recombinant glycan knockout gp120 variants to identify the precise Env binding site for MVN that drives DLI engagement and lysis. Using mutagenesis combined with a series of biophysical and virological experiments, we identified a restricted set of residues, N262, N332 and N448, all localized in a cluster on the outer domain of gp120, as the essential epitope for MVN binding. By generating these mutations in the corresponding HIV-1 virus, we established that the engagement of this glycan cluster with the lectin domain of MVN*-DLI is the trigger for DLI-derived virus and cell inactivation. Beyond defining the initial encounter step for lytic inactivation, this study provides a guide to further elucidate DLI mechanism, including the stoichiometry of Env trimer required for function, and downstream DLI optimization.
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Affiliation(s)
- Bibek Parajuli
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Kriti Acharya
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Aakansha Nangarlia
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Shiyu Zhang
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Bijay Parajuli
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Alexej Dick
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Brendon Ngo
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Cameron F Abrams
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, PA 19104, U.S.A
| | - Irwin Chaiken
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
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7
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Galili U. Amplifying immunogenicity of prospective Covid-19 vaccines by glycoengineering the coronavirus glycan-shield to present α-gal epitopes. Vaccine 2020; 38:6487-6499. [PMID: 32907757 PMCID: PMC7437500 DOI: 10.1016/j.vaccine.2020.08.032] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 07/22/2020] [Accepted: 08/12/2020] [Indexed: 12/16/2022]
Abstract
The many carbohydrate chains on Covid-19 coronavirus SARS-CoV-2 and its S-protein form a glycan-shield that masks antigenic peptides and decreases uptake of inactivated virus or S-protein vaccines by APC. Studies on inactivated influenza virus and recombinant gp120 of HIV vaccines indicate that glycoengineering of glycan-shields to present α-gal epitopes (Galα1-3Galβ1-4GlcNAc-R) enables harnessing of the natural anti-Gal antibody for amplifying vaccine efficacy, as evaluated in mice producing anti-Gal. The α-gal epitope is the ligand for the natural anti-Gal antibody which constitutes ~1% of immunoglobulins in humans. Upon administration of vaccines presenting α-gal epitopes, anti-Gal binds to these epitopes at the vaccination site and forms immune complexes with the vaccines. These immune complexes are targeted for extensive uptake by APC as a result of binding of the Fc portion of immunocomplexed anti-Gal to Fc receptors on APC. This anti-Gal mediated effective uptake of vaccines by APC results in 10-200-fold higher anti-viral immune response and in 8-fold higher survival rate following challenge with a lethal dose of live influenza virus, than same vaccines lacking α-gal epitopes. It is suggested that glycoengineering of carbohydrate chains on the glycan-shield of inactivated SARS-CoV-2 or on S-protein vaccines, for presenting α-gal epitopes, will have similar amplifying effects on vaccine efficacy. α-Gal epitope synthesis on coronavirus vaccines can be achieved with recombinant α1,3galactosyltransferase, replication of the virus in cells with high α1,3galactosyltransferase activity as a result of stable transfection of cells with several copies of the α1,3galactosyltransferase gene (GGTA1), or by transduction of host cells with replication defective adenovirus containing this gene. In addition, recombinant S-protein presenting multiple α-gal epitopes on the glycan-shield may be produced in glycoengineered yeast or bacteria expression systems containing the corresponding glycosyltransferases. Prospective Covid-19 vaccines presenting α-gal epitopes may provide better protection than vaccines lacking this epitope because of increased uptake by APC.
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MESH Headings
- Animals
- Antibodies, Viral/biosynthesis
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- Antigens, Viral/metabolism
- Betacoronavirus/drug effects
- Betacoronavirus/immunology
- Betacoronavirus/pathogenicity
- COVID-19
- COVID-19 Vaccines
- Coronavirus Infections/genetics
- Coronavirus Infections/immunology
- Coronavirus Infections/prevention & control
- Coronavirus Infections/virology
- Dendritic Cells/drug effects
- Dendritic Cells/immunology
- Dendritic Cells/virology
- Genetic Engineering
- HIV Core Protein p24/chemistry
- HIV Core Protein p24/genetics
- HIV Core Protein p24/immunology
- HIV Envelope Protein gp120/chemistry
- HIV Envelope Protein gp120/genetics
- HIV Envelope Protein gp120/immunology
- Humans
- Immunogenicity, Vaccine
- Macrophages/drug effects
- Macrophages/immunology
- Macrophages/virology
- Mice
- Pandemics/prevention & control
- Pneumonia, Viral/immunology
- Pneumonia, Viral/prevention & control
- Pneumonia, Viral/virology
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/immunology
- SARS-CoV-2
- Spike Glycoprotein, Coronavirus/genetics
- Spike Glycoprotein, Coronavirus/immunology
- Spike Glycoprotein, Coronavirus/metabolism
- Trisaccharides/chemistry
- Trisaccharides/immunology
- Viral Vaccines/administration & dosage
- Viral Vaccines/biosynthesis
- Viral Vaccines/genetics
- Viral Vaccines/immunology
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Affiliation(s)
- Uri Galili
- Department of Medicine, Rush Medical School, Chicago, IL, USA.
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8
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Ohyama Y, Nakajima K, Renfrow MB, Novak J, Takahashi K. Mass spectrometry for the identification and analysis of highly complex glycosylation of therapeutic or pathogenic proteins. Expert Rev Proteomics 2020; 17:275-296. [PMID: 32406805 DOI: 10.1080/14789450.2020.1769479] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Protein glycosylation influences characteristics such as folding, stability, protein interactions, and solubility. Therefore, glycan moieties of therapeutic proteins and proteins that are likely associated with disease pathogenesis should be analyzed in-depth, including glycan heterogeneity and modification sites. Recent advances in analytical methods and instrumentation have enabled comprehensive characterization of highly complex glycosylated proteins. AREA COVERED The following aspects should be considered when analyzing glycosylated proteins: sample preparation, chromatographic separation, mass spectrometry (MS) and fragmentation methods, and bioinformatics, such as software solutions for data analyses. Notably, analysis of glycoproteins with heavily sialylated glycans or multiple glycosylation sites requires special considerations. Here, we discuss recent methodological advances in MS that provide detailed characterization of heterogeneous glycoproteins. EXPERT OPINION As characterization of complex glycosylated proteins is still analytically challenging, the function or pathophysiological significance of these proteins is not fully understood. To reproducibly produce desired forms of therapeutic glycoproteins or to fully elucidate disease-specific patterns of protein glycosylation, a highly reproducible and robust analytical platform(s) should be established. In addition to advances in MS instrumentation, optimization of analytical and bioinformatics methods and utilization of glycoprotein/glycopeptide standards is desirable. Ultimately, we envision that an automated high-throughput MS analysis will provide additional power to clinical studies and precision medicine.
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Affiliation(s)
- Yukako Ohyama
- Department of Nephrology, Fujita Health University School of Medicine , Toyoake, Japan.,Department of Biomedical Molecular Sciences, Fujita Health University School of Medicine , Toyoake, Japan
| | - Kazuki Nakajima
- Center for Research Promotion and Support, Fujita Health University , Toyoake, Japan
| | - Matthew B Renfrow
- Departments of Biochemistry and Molecular Genetics and Microbiology, University of Alabama at Birmingham , Birmingham, AL, USA
| | - Jan Novak
- Departments of Biochemistry and Molecular Genetics and Microbiology, University of Alabama at Birmingham , Birmingham, AL, USA
| | - Kazuo Takahashi
- Department of Nephrology, Fujita Health University School of Medicine , Toyoake, Japan.,Department of Biomedical Molecular Sciences, Fujita Health University School of Medicine , Toyoake, Japan.,Departments of Biochemistry and Molecular Genetics and Microbiology, University of Alabama at Birmingham , Birmingham, AL, USA
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9
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Cooperation between somatic mutation and germline-encoded residues enables antibody recognition of HIV-1 envelope glycans. PLoS Pathog 2019; 15:e1008165. [PMID: 31841553 PMCID: PMC6936856 DOI: 10.1371/journal.ppat.1008165] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 12/30/2019] [Accepted: 10/29/2019] [Indexed: 11/19/2022] Open
Abstract
Viral glycoproteins are a primary target for host antibody responses. However, glycans on viral glycoproteins can hinder antibody recognition since they are self glycans derived from the host biosynthesis pathway. During natural HIV-1 infection, neutralizing antibodies are made against glycans on HIV-1 envelope glycoprotein (Env). However, such antibodies are rarely elicited with vaccination. Previously, the vaccine-induced, macaque antibody DH501 was isolated and shown to bind to high mannose glycans on HIV-1 Env. Understanding how DH501 underwent affinity maturation to recognize glycans could inform vaccine induction of HIV-1 glycan antibodies. Here, we show that DH501 Env glycan reactivity is mediated by both germline-encoded residues that contact glycans, and somatic mutations that increase antibody paratope flexibility. Only somatic mutations in the heavy chain were required for glycan reactivity. The paratope conformation was fragile as single mutations within the immunoglobulin fold or complementarity determining regions were sufficient for eliminating antibody function. Taken together, the initial germline VHDJH rearrangement generated contact residues capable of binding glycans, and somatic mutations were required to form a flexible paratope with a cavity conducive to HIV-1 envelope glycan binding. The requirement for the presence of most somatic mutations across the heavy chain variable region provides one explanation for the difficulty in inducing anti-Env glycan antibodies with HIV-1 Env vaccination. The viral pathogen HIV-1 uses sugar molecules, called glycans, from the host to densely cover its envelope protein. Most broadly neutralizing HIV-1 antibodies interact with glycans on the HIV-1 envelope protein. For this reason, the vaccine induction of anti-HIV-1 glycan antibodies is a principal goal. Since vaccine-induced anti-HIV-1 glycan antibodies are rare, it has not been determined how antibodies develop during vaccination to recognize HIV-1 glycans. Here, we elucidated the amino acids required for a primate antibody induced by HIV-1 vaccination to interact with HIV envelope glycans. Genetic and functional analyses showed the putative antibody germline nucleotide sequence encoded amino acids that were required for glycan reactivity. Somatic mutation also introduced critical amino acids that were required for glycan recognition. Unusually, the somatic mutations were not required in order to form direct contacts with antigen, but instead functioned to improve antibody flexibility and to form its glycan binding site. These results define the molecular development of a vaccine-induced HIV-1 glycan antibody, providing insight into why vaccines rarely elicit antibodies against the glycans on the HIV-1 outer coat protein.
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10
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Behren S, Westerlind U. Glycopeptides and -Mimetics to Detect, Monitor and Inhibit Bacterial and Viral Infections: Recent Advances and Perspectives. Molecules 2019; 24:E1004. [PMID: 30871155 PMCID: PMC6471658 DOI: 10.3390/molecules24061004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/06/2019] [Accepted: 03/07/2019] [Indexed: 11/17/2022] Open
Abstract
The initial contact of pathogens with host cells is usually mediated by their adhesion to glycan structures present on the cell surface in order to enable infection. Furthermore, glycans play important roles in the modulation of the host immune responses to infection. Understanding the carbohydrate-pathogen interactions are of importance for the development of novel and efficient strategies to either prevent, or interfere with pathogenic infection. Synthetic glycopeptides and mimetics thereof are capable of imitating the multivalent display of carbohydrates at the cell surface, which have become an important objective of research over the last decade. Glycopeptide based constructs may function as vaccines or anti-adhesive agents that interfere with the ability of pathogens to adhere to the host cell glycans and thus possess the potential to improve or replace treatments that suffer from resistance. Additionally, synthetic glycopeptides are used as tools for epitope mapping of antibodies directed against structures present on various pathogens and have become important to improve serodiagnostic methods and to develop novel epitope-based vaccines. This review will provide an overview of the most recent advances in the synthesis and application of glycopeptides and glycopeptide mimetics exhibiting a peptide-like backbone in glycobiology.
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Affiliation(s)
- Sandra Behren
- Department of Chemistry, Umeå University, 90187 Umeå, Sweden.
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11
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Sun L, Ishihara M, Middleton DR, Tiemeyer M, Avci FY. Metabolic labeling of HIV-1 envelope glycoprotein gp120 to elucidate the effect of gp120 glycosylation on antigen uptake. J Biol Chem 2018; 293:15178-15194. [PMID: 30115684 DOI: 10.1074/jbc.ra118.004798] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/12/2018] [Indexed: 12/21/2022] Open
Abstract
The glycan shield on the envelope glycoprotein gp120 of HIV-1 has drawn immense attention as a vulnerable site for broadly neutralizing antibodies and for its significant impact on host adaptive immune response to HIV-1. Glycosylation sites and glycan composition/structure at each site on gp120 along with the interactions of gp120 glycan shield with broadly neutralizing antibodies have been extensively studied. However, a method for directly and selectively tracking gp120 glycans has been lacking. Here, we integrate metabolic labeling and click chemistry technology with recombinant gp120 expression to demonstrate that gp120 glycans could be specifically labeled and directly detected. Selective labeling of gp120 by N-azidoacetylmannosamine (ManNAz) and N-azidoacetylgalactosamine (GalNAz) incorporation into the gp120 glycan shield was characterized by MS of tryptic glycopeptides. By using metabolically labeled gp120, we investigated the impact of gp120 glycosylation on its interaction with host cells and demonstrated that oligomannose enrichment and sialic acid deficiency drastically enhanced gp120 uptake by bone marrow-derived dendritic cells. Collectively, our data reveal an effective labeling and detection method for gp120, serving as a tool for functional characterization of the gp120 glycans and potentially other glycosylated proteins.
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Affiliation(s)
- Lina Sun
- From the Department of Biochemistry and Molecular Biology, Center for Molecular Medicine and
| | - Mayumi Ishihara
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Dustin R Middleton
- From the Department of Biochemistry and Molecular Biology, Center for Molecular Medicine and
| | - Michael Tiemeyer
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Fikri Y Avci
- From the Department of Biochemistry and Molecular Biology, Center for Molecular Medicine and .,Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
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12
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Affiliation(s)
- David J. Harvey
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Biological Sciences and the Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
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13
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Restricted HIV-1 Env glycan engagement by lectin-reengineered DAVEI protein chimera is sufficient for lytic inactivation of the virus. Biochem J 2018; 475:931-957. [PMID: 29343613 DOI: 10.1042/bcj20170662] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Revised: 12/28/2017] [Accepted: 01/17/2018] [Indexed: 12/28/2022]
Abstract
We previously reported a first-generation recombinant DAVEI construct, a dual action virus entry inhibitor composed of cyanovirin-N (CVN) fused to a membrane proximal external region or its derivative peptide Trp3. DAVEI exhibits potent and irreversible inactivation of HIV-1 (human immunodeficiency virus) viruses by dual engagement of gp120 and gp41. However, the promiscuity of CVN to associate with multiple glycosylation sites in gp120 and its multivalency limit current understanding of the molecular arrangement of the DAVEI molecules on trimeric spike. Here, we constructed and investigated the virolytic function of second-generation DAVEI molecules using a simpler lectin, microvirin (MVN). MVN is a monovalent lectin with a single glycan-binding site in gp120, is structurally similar to CVN and exhibits no toxicity or mitogenicity, both of which are liabilities with CVN. We found that, like CVN-DAVEI-L2-3Trp (peptide sequence DKWASLWNW), MVN-DAVEI2-3Trp exploits a similar mechanism of action for inducing HIV-1 lytic inactivation, but by more selective gp120 glycan engagement. By sequence redesign, we significantly increased the potency of MVN-DAVEI2-3Trp protein. Unlike CVN-DAVEI2-3Trp, re-engineered MVN-DAVEI2-3Trp(Q81K/M83R) virolytic activity and its interaction with gp120 were both competed by 2G12 antibody. That the lectin domain in DAVEIs can utilize MVN without loss of virolytic function argues that restricted HIV-1 Env (envelope glycoprotein) glycan engagement is sufficient for virolysis. It also shows that DAVEI lectin multivalent binding with gp120 is not required for virolysis. MVN-DAVEI2-3Trp(Q81K/M83R) provides an improved tool to elucidate productive molecular arrangements of Env-DAVEI enabling virolysis and also opens the way to form DAVEI fusions made up of gp120-binding small molecules linked to Trp3 peptide.
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14
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Behrens AJ, Crispin M. Structural principles controlling HIV envelope glycosylation. Curr Opin Struct Biol 2017; 44:125-133. [PMID: 28363124 DOI: 10.1016/j.sbi.2017.03.008] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/09/2017] [Accepted: 03/14/2017] [Indexed: 12/21/2022]
Abstract
The heavily glycosylated, trimeric HIV-1 envelope (Env) protein is the sole viral protein exposed on the HIV-1 virion surface and is thus a main focus of antibody-mediated vaccine development. Dense glycosylation at the outer domain of Env constrains normal enzymatic processing, stalling the glycans at immature oligomannose-type structures. Furthermore, native trimerization imposes additional steric constraints, which generate an extensive 'trimer-induced mannose patch'. Importantly, the immature glycans present a highly conserved feature of the virus that is targeted by broadly neutralizing antibodies. Quantitative mass spectrometry of glycopeptides together with structures of the trimeric viral-spike define the steric principles controlling processing and provide a detailed map of the glycan shield.
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Affiliation(s)
- Anna-Janina Behrens
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Max Crispin
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK; Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA.
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15
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Farzan N, Vijverberg SJH, Arets HG, Raaijmakers JAM, Maitland-van der Zee AH. Pharmacogenomics of inhaled corticosteroids and leukotriene modifiers: a systematic review. Clin Exp Allergy 2016; 47:271-293. [PMID: 27790783 DOI: 10.1111/cea.12844] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 10/17/2016] [Accepted: 10/20/2016] [Indexed: 01/02/2023]
Abstract
BACKGROUND Pharmacogenetics studies of anti-inflammatory medication of asthma have expanded rapidly in recent decades, but the clinical value of their findings remains limited. OBJECTIVE To perform a systematic review of pharmacogenomics and pharmacogenetics of inhaled corticosteroids (ICS) and leukotriene modifiers (LTMs) in patients with asthma. METHODS Articles published between 1999 and June 2015 were searched using PubMed and EMBASE. Pharmacogenomics/genetics studies of patients with asthma using ICS or LTMs were included if ≥1 of the following outcomes were studied: lung function, exacerbation rates or asthma symptoms. The studies of Single Nucleotide Polymorphisms (SNPs) that had been replicated at least once were assessed in more detail. RESULTS In total, 59 publications were included in the systematic review: 26 addressed LTMs (including two genomewide Genome-Wide association studies [GWAS]) and 33 addressed ICS (including four GWAS). None of the GWAS reported similar results. Furthermore, none of the SNPs assessed in candidate gene studies were identified in a GWAS. No consistent reports were found for candidate gene studies of LTMs. In candidate gene studies of ICS, the most consistent results were found for rs28364072 in FCER2. This SNP was associated with all three outcomes of poor response, and the largest effect was reported with the risk of exacerbations (hazard ratio, 3.95; 95% CI, 1.64-9.51). CONCLUSION AND CLINICAL RELEVANCE There is a lack of replication of genetic variants associated with poor ICS or LTM response. The most consistent results were found for the FCER2 gene [encoding for a low-affinity IgE receptor (CD23)] and poor ICS response. Larger studies with well-phenotyped patients are needed to assess the clinical applicability of ICS and LTM pharmacogenomics/genetics.
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Affiliation(s)
- N Farzan
- Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands.,Department of Respiratory Medicine, Academic Medical Center (AMC), University of Amsterdam, Amsterdam, the Netherlands
| | - S J H Vijverberg
- Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands.,Department of Respiratory Medicine, Academic Medical Center (AMC), University of Amsterdam, Amsterdam, the Netherlands
| | - H G Arets
- Department of Paediatric Pulmonology, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - J A M Raaijmakers
- Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands
| | - A H Maitland-van der Zee
- Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands.,Department of Respiratory Medicine, Academic Medical Center (AMC), University of Amsterdam, Amsterdam, the Netherlands
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16
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HIV-1 Glycan Density Drives the Persistence of the Mannose Patch within an Infected Individual. J Virol 2016; 90:11132-11144. [PMID: 27707925 PMCID: PMC5126371 DOI: 10.1128/jvi.01542-16] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 09/26/2016] [Indexed: 12/15/2022] Open
Abstract
The HIV envelope glycoprotein (Env) is extensively modified with host-derived N-linked glycans. The high density of glycosylation on the viral spike limits enzymatic processing, resulting in numerous underprocessed oligomannose-type glycans. This extensive glycosylation not only shields conserved regions of the protein from the immune system but also acts as a target for anti-HIV broadly neutralizing antibodies (bnAbs). In response to the host immune system, the HIV glycan shield is constantly evolving through mutations affecting both the positions and numbers of potential N-linked glycosylation sites (PNGSs). Here, using longitudinal Env sequences from a clade C-infected individual (CAP256), we measured the impact of the shifting glycan shield during HIV infection on the abundance of oligomannose-type glycans. By analyzing the intrinsic mannose patch from a panel of recombinant CAP256 gp120s displaying high protein sequence variability and changes in PNGS number and positioning, we show that the intrinsic mannose patch persists throughout the course of HIV infection and correlates with the number of PNGSs. This effect of the glycan density on the processing state was also supported by the analysis of a cross-clade panel of recombinant gp120 glycoproteins. Together, these observations underscore the importance of glycan clustering for the generation of carbohydrate epitopes for anti-HIV bnAbs. The persistence of the intrinsic mannose patch over the course of HIV infection further highlights this epitope as an important target for HIV vaccine strategies. IMPORTANCE Development of an HIV vaccine is critical for control of the HIV pandemic, and elicitation of broadly neutralizing antibodies (bnAbs) is likely to be a key component of a successful vaccine response. The HIV envelope glycoprotein (Env) is covered in an array of host-derived N-linked glycans often referred to as the glycan shield. This glycan shield is a target for many of the recently isolated anti-HIV bnAbs and is therefore under constant pressure from the host immune system, leading to changes in both glycan site frequency and location. This study aimed to determine whether these genetic changes impacted the eventual processing of glycans on the HIV Env and the susceptibility of the virus to neutralization. We show that despite this variation in glycan site positioning and frequency over the course of HIV infection, the mannose patch is a conserved feature throughout, making it a stable target for HIV vaccine design.
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17
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Dahlin A, Litonjua A, Irvin CG, Peters SP, Lima JJ, Kubo M, Tamari M, Tantisira KG. Genome-wide association study of leukotriene modifier response in asthma. THE PHARMACOGENOMICS JOURNAL 2016; 16:151-7. [PMID: 26031901 PMCID: PMC4668236 DOI: 10.1038/tpj.2015.34] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 11/19/2014] [Accepted: 01/28/2015] [Indexed: 01/08/2023]
Abstract
Heterogeneous therapeutic responses to leukotriene modifiers (LTMs) are likely due to variation in patient genetics. Although prior candidate gene studies implicated multiple pharmacogenetic loci, to date, no genome-wide association study (GWAS) of LTM response was reported. In this study, DNA and phenotypic information from two placebo-controlled trials (total N=526) of zileuton response were interrogated. Using a gene-environment (G × E) GWAS model, we evaluated 12-week change in forced expiratory volume in 1 second (ΔFEV1) following LTM treatment. The top 50 single-nucleotide polymorphism associations were replicated in an independent zileuton treatment cohort, and two additional cohorts of montelukast response. In a combined analysis (discovery+replication), rs12436663 in MRPP3 achieved genome-wide significance (P=6.28 × 10(-08)); homozygous rs12436663 carriers showed a significant reduction in mean ΔFEV1 following zileuton treatment. In addition, rs517020 in GLT1D1 was associated with worsening responses to both montelukast and zileuton (combined P=1.25 × 10(-07)). These findings implicate previously unreported loci in determining therapeutic responsiveness to LTMs.
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Affiliation(s)
- A Dahlin
- Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - A Litonjua
- Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - C G Irvin
- Department of Medicine, University of Vermont, Burlington, VT, USA
| | - S P Peters
- Center for Genomics and Personalized Medicine Research, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - J J Lima
- Center for Pharmacogenomics and Translational Research, Nemours Children's Clinic, Jacksonville, FL, USA
| | - M Kubo
- Center for Integrative Medical Sciences, Riken, Yokohama, Japan
| | - M Tamari
- Center for Integrative Medical Sciences, Riken, Yokohama, Japan
| | - K G Tantisira
- Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
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18
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Doores KJ. The HIV glycan shield as a target for broadly neutralizing antibodies. FEBS J 2015; 282:4679-91. [PMID: 26411545 PMCID: PMC4950053 DOI: 10.1111/febs.13530] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 09/21/2015] [Accepted: 09/23/2015] [Indexed: 11/30/2022]
Abstract
The HIV envelope glycoprotein (Env) is the sole target for HIV broadly neutralizing antibodies (bnAbs). HIV Env is one of the most heavily glycosylated proteins known, with approximately half of its mass consisting of host-derived N-linked glycans. The high density of glycans creates a shield that impedes antibody recognition but, critically, some of the most potent and broadly active bnAbs have evolved to recognize epitopes formed by these glycans. Although the virus hijacks the host protein synthesis and glycosylation machinery to generate glycosylated HIV Env, studies have shown that HIV Env glycosylation diverges from that typically observed on host-derived glycoproteins. In particular, the high density of glycans leads to a nonself motif of underprocessed oligomannose-type glycans that forms the target of some of the most broad and potent HIV bnAbs. This review discusses the changing perception of the HIV glycan shield, and summarizes the protein-directed and cell-directed factors controlling HIV Env glycosylation that impact on HIV bnAb recognition and HIV vaccine design strategies.
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Affiliation(s)
- Katie J Doores
- Department of Infectious Diseases, Faculty of Life Sciences and Medicine, King's College London, Guy's Hospital, UK
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19
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Clark GF. The role of glycans in immune evasion: the human fetoembryonic defence system hypothesis revisited. Mol Hum Reprod 2014; 20:185-99. [PMID: 24043694 PMCID: PMC3925329 DOI: 10.1093/molehr/gat064] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 08/15/2013] [Accepted: 09/03/2013] [Indexed: 02/06/2023] Open
Abstract
Emerging data suggest that mechanisms to evade the human immune system may be shared by the conceptus, tumour cells, persistent pathogens and viruses. It is therefore timely to revisit the human fetoembryonic defense system (Hu-FEDS) hypothesis that was proposed in two papers in the 1990s. The initial paper suggested that glycoconjugates expressed in the human reproductive system inhibited immune responses directed against gametes and the developing human by employing their carbohydrate sequences as functional groups. These glycoconjugates were proposed to block specific binding interactions and interact with lectins linked to signal transduction pathways that modulated immune cell functions. The second article suggested that aggressive tumour cells and persistent pathogens (HIV, H. pylori, schistosomes) either mimicked or acquired the same carbohydrate functional groups employed in this system to evade immune responses. This subterfuge enabled these pathogens and tumour cells to couple their survival to the human reproductive imperative. The Hu-FEDS model has been repeatedly tested since its inception. Data relevant to this model have also been obtained in other studies. Herein, the Hu-FEDS hypothesis is revisited in the context of these more recent findings. Far more supportive evidence for this model now exists than when it was first proposed, and many of the original predictions have been validated. This type of subterfuge by pathogens and tumour cells likely applies to all sexually reproducing metazoans that must protect their gametes from immune responses. Intervention in these pathological states will likely remain problematic until this system of immune evasion is fully understood and appreciated.
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Affiliation(s)
- Gary F. Clark
- Department of Obstetrics, Gynecology and Women's Health, Division of Reproductive and Perinatal Research and Division of Reproductive Medicine and Fertility, University of Missouri School of Medicine, Columbia, MO 65211, USA
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20
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Pancera M, Shahzad-Ul-Hussan S, Doria-Rose NA, McLellan JS, Bailer RT, Dai K, Loesgen S, Louder MK, Staupe RP, Yang Y, Zhang B, Parks R, Eudailey J, Lloyd KE, Blinn J, Alam SM, Haynes BF, Amin MN, Wang LX, Burton DR, Koff WC, Nabel GJ, Mascola JR, Bewley CA, Kwong PD. Structural basis for diverse N-glycan recognition by HIV-1-neutralizing V1-V2-directed antibody PG16. Nat Struct Mol Biol 2013; 20:804-13. [PMID: 23708607 PMCID: PMC4046252 DOI: 10.1038/nsmb.2600] [Citation(s) in RCA: 236] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 05/02/2013] [Indexed: 11/08/2022]
Abstract
HIV-1 uses a diverse N-linked-glycan shield to evade recognition by antibody. Select human antibodies, such as the clonally related PG9 and PG16, recognize glycopeptide epitopes in the HIV-1 V1-V2 region and penetrate this shield, but their ability to accommodate diverse glycans is unclear. Here we report the structure of antibody PG16 bound to a scaffolded V1-V2, showing an epitope comprising both high mannose-type and complex-type N-linked glycans. We combined structure, NMR and mutagenesis analyses to characterize glycan recognition by PG9 and PG16. Three PG16-specific residues, arginine, serine and histidine (RSH), were critical for binding sialic acid on complex-type glycans, and introduction of these residues into PG9 produced a chimeric antibody with enhanced HIV-1 neutralization. Although HIV-1-glycan diversity facilitates evasion, antibody somatic diversity can overcome this and can provide clues to guide the design of modified antibodies with enhanced neutralization.
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Affiliation(s)
- Marie Pancera
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, US National Institutes of Health, Bethesda, Maryland, USA
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21
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Lech PJ, Tobin GJ, Bushnell R, Gutschenritter E, Pham LD, Nace R, Verhoeyen E, Cosset FL, Muller CP, Russell SJ, Nara PL. Epitope dampening monotypic measles virus hemagglutinin glycoprotein results in resistance to cocktail of monoclonal antibodies. PLoS One 2013; 8:e52306. [PMID: 23300970 PMCID: PMC3536790 DOI: 10.1371/journal.pone.0052306] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 11/16/2012] [Indexed: 12/21/2022] Open
Abstract
The measles virus (MV) is serologically monotypic. Life-long immunity is conferred by a single attack of measles or following vaccination with the MV vaccine. This is contrary to viruses such as influenza, which readily develop resistance to the immune system and recur. A better understanding of factors that restrain MV to one serotype may allow us to predict if MV will remain monotypic in the future and influence the design of novel MV vaccines and therapeutics. MV hemagglutinin (H) glycoprotein, binds to cellular receptors and subsequently triggers the fusion (F) glycoprotein to fuse the virus into the cell. H is also the major target for neutralizing antibodies. To explore if MV remains monotypic due to a lack of plasticity of the H glycoprotein, we used the technology of Immune Dampening to generate viruses with rationally designed N-linked glycosylation sites and mutations in different epitopes and screened for viruses that escaped monoclonal antibodies (mAbs). We then combined rationally designed mutations with naturally selected mutations to generate a virus resistant to a cocktail of neutralizing mAbs targeting four different epitopes simultaneously. Two epitopes were protected by engineered N-linked glycosylations and two epitopes acquired escape mutations via two consecutive rounds of artificial selection in the presence of mAbs. Three of these epitopes were targeted by mAbs known to interfere with receptor binding. Results demonstrate that, within the epitopes analyzed, H can tolerate mutations in different residues and additional N-linked glycosylations to escape mAbs. Understanding the degree of change that H can tolerate is important as we follow its evolution in a host whose immunity is vaccine induced by genotype A strains instead of multiple genetically distinct wild-type MVs.
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Affiliation(s)
- Patrycja J Lech
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, United States of America.
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22
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Kong L, Julien JP, Calarese D, Scanlan C, Lee HK, Rudd P, Wong CH, Dwek RA, Burton DR, Wilson IA. Toward a Carbohydrate-Based HIV-1 Vaccine. ACTA ACUST UNITED AC 2012. [DOI: 10.1021/bk-2012-1102.ch007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Affiliation(s)
- Leopold Kong
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037
- The Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Jean-Philippe Julien
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037
- The Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Daniel Calarese
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037
- The Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Christopher Scanlan
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037
- The Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Hing-Ken Lee
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037
- The Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Pauline Rudd
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037
- The Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Chi-Huey Wong
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037
- The Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Raymond A. Dwek
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037
- The Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Dennis R. Burton
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037
- The Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Ian A. Wilson
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037
- The Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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23
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Nachmias D, Sklan EH, Ehrlich M, Bacharach E. Human immunodeficiency virus type 1 envelope proteins traffic toward virion assembly sites via a TBC1D20/Rab1-regulated pathway. Retrovirology 2012; 9:7. [PMID: 22260459 PMCID: PMC3283470 DOI: 10.1186/1742-4690-9-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 01/19/2012] [Indexed: 01/08/2023] Open
Abstract
Background The cellular activity of many factors and pathways is required to execute the complex replication cycle of the human immunodeficiency virus type 1 (HIV-1). To reveal these cellular components, several extensive RNAi screens have been performed, listing numerous 'HIV-dependency factors'. However, only a small overlap between these lists exists, calling for further evaluation of the relevance of specific factors to HIV-1 replication and for the identification of additional cellular candidates. TBC1D20, the GTPase-activating protein (GAP) of Rab1, regulates endoplasmic reticulum (ER) to Golgi trafficking, was not identified in any of these screens, and its involvement in HIV-1 replication cycle is tested here. Findings Excessive TBC1D20 activity perturbs the early trafficking of HIV-1 envelope protein through the secretory pathway. Overexpression of TBC1D20 hampered envelope processing and reduced its association with detergent-resistant membranes, entailing a reduction in infectivity of HIV-1 virion like particles (VLPs). Conclusions These findings add TBC1D20 to the network of host factors regulating HIV replication cycle.
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Affiliation(s)
- Dikla Nachmias
- Department of Cell Research and Immunology, The George S, Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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24
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High-mannose glycan-dependent epitopes are frequently targeted in broad neutralizing antibody responses during human immunodeficiency virus type 1 infection. J Virol 2011; 86:2153-64. [PMID: 22156525 DOI: 10.1128/jvi.06201-11] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Broad and potent neutralizing antibody (BNAb) responses are rare in people infected by human immunodeficiency virus type 1 (HIV-1). Clearly defining the nature of BNAb epitopes on HIV-1 envelope glycoproteins (Envs) targeted in vivo is critical for future directions of anti-HIV-1 vaccine development. Conventional techniques are successful in defining neutralizing epitopes in a small number of individual subjects but fail in studying large groups of subjects. Two independent methods were employed to investigate the nature of NAb epitopes targeted in 9 subjects, identified by the NIAID Center for HIV/AIDS Vaccine Immunology (CHAVI) 001 and 008 clinical teams, known to make a strong BNAb response. Neutralizing activity from 8/9 subjects was enhanced by enriching high-mannose N-linked glycan (HM-glycan) of HIV-1 glycoproteins on neutralization target viruses and was sensitive to specific glycan deletion mutations of HIV-1 glycoproteins, indicating that HM-glycan-dependent epitopes are targeted by BNAb responses in these subjects. This discovery adds to accumulating evidence supporting the hypothesis that glycans are important targets on HIV-1 glycoproteins for BNAb responses in vivo, providing an important lead for future directions in developing NAb-based anti-HIV-1 vaccines.
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25
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Host-soluble galectin-1 promotes HIV-1 replication through a direct interaction with glycans of viral gp120 and host CD4. J Virol 2011; 85:11742-51. [PMID: 21880749 DOI: 10.1128/jvi.05351-11] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sexual transmission of HIV-1 requires virus adsorption to a target cell, typically a CD4(+) T lymphocyte residing in the lamina propria, beneath the epithelium. To escape the mucosal clearance system and reach its target cells, HIV-1 has evolved strategies to circumvent deleterious host factors. Galectin-1, a soluble lectin found in the underlayers of the epithelium, increases HIV-1 infectivity by accelerating its binding to susceptible cells. By comparison, galectin-3, a family member expressed by epithelial cells and part of the mucosal clearance system, does not perform similarly. We show here that galectin-1 directly binds to HIV-1 in a β-galactoside-dependent fashion through recognition of clusters of N-linked glycans on the viral envelope gp120. Unexpectedly, this preferential binding of galectin-1 does not rely on the primary sequence of any particular glycans. Instead, glycan clustering arising from the tertiary structure of gp120 hinders its binding by galectin-3. Increased polyvalency of a specific ligand epitope is a common strategy for glycans to increase their avidity for lectins. In this peculiar occurrence, glycan clustering is instead exploited to prevent binding of gp120 by galectin-3, which would lead to a biological dead-end for the virus. Our data also suggest that galectin-1 binds preferentially to CD4, the host receptor for gp120. Together, these results suggest that HIV-1 exploits galectin-1 to enhance gp120-CD4 interactions, thereby promoting virus attachment and infection events. Since viral adhesion is a rate-limiting step for HIV-1 entry, modulation of the gp120 interaction with galectin-1 could thus represent a novel approach for the prevention of HIV-1 transmission.
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26
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Shahzad-ul-Hussan S, Gustchina E, Ghirlando R, Clore GM, Bewley CA. Solution structure of the monovalent lectin microvirin in complex with Man(alpha)(1-2)Man provides a basis for anti-HIV activity with low toxicity. J Biol Chem 2011; 286:20788-96. [PMID: 21471192 PMCID: PMC3121468 DOI: 10.1074/jbc.m111.232678] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 03/23/2011] [Indexed: 11/06/2022] Open
Abstract
Lectins that bind surface envelope glycoprotein gp120 of HIV with high avidity can potently inhibit viral entry. Yet properties such as multivalency that facilitate strong interactions can also cause nonspecific binding and toxicity. The cyanobacterial lectin microvirin (MVN) is unusual as it potently inhibits HIV-1 with negligible toxicity compared with cyanovirin-N (CVN), its well studied antiviral homolog. To understand the structural and mechanistic basis for these differences, we solved the solution structure of MVN free and in complex with its ligand Manα(1-2)Man, and we compared specificity and time windows of inhibition with CVN and Manα(1-2)Man-specific mAb 2G12. We show by NMR and analytical ultracentrifugation that MVN is monomeric in solution, and we demonstrate by NMR that Manα(1-2)Man-terminating carbohydrates interact with a single carbohydrate-binding site. Synchronized infectivity assays show that 2G12, MVN, and CVN inhibit entry with distinct kinetics. Despite shared specificity for Manα(1-2)Man termini, combinations of the inhibitors are synergistic suggesting they recognize discrete glycans and/or dynamic glycan conformations on gp120. Entry assays employing amphotropic viruses show that MVN is inactive, whereas CVN potently inhibits both. In addition to demonstrating that HIV-1 can be inhibited through monovalent interactions, given the similarity of the carbohydrate-binding site common to MVN and CVN, these data suggest that gp120 behaves as a clustered glycan epitope and that multivalent-protein interactions achievable with CVN but not MVN are required for inhibition of some viruses.
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Affiliation(s)
| | | | - Rodolfo Ghirlando
- the Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
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27
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Characterization of glycosylation profiles of HIV-1 transmitted/founder envelopes by mass spectrometry. J Virol 2011; 85:8270-84. [PMID: 21653661 DOI: 10.1128/jvi.05053-11] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The analysis of HIV-1 envelope carbohydrates is critical to understanding their roles in HIV-1 transmission as well as in binding of envelope to HIV-1 antibodies. However, direct analysis of protein glycosylation by glycopeptide-based mass mapping approaches involves structural simplification of proteins with the use of a protease followed by an isolation and/or enrichment step before mass analysis. The successful completion of glycosylation analysis is still a major analytical challenge due to the complexity of samples, wide dynamic range of glycopeptide concentrations, and glycosylation heterogeneity. Here, we use a novel experimental workflow that includes an up-front complete or partial enzymatic deglycosylation step before trypsin digestion to characterize the glycosylation patterns and maximize the glycosylation coverage of two recombinant HIV-1 transmitted/founder envelope oligomers derived from clade B and C viruses isolated from acute infection and expressed in 293T cells. Our results show that both transmitted/founder Envs had similar degrees of glycosylation site occupancy as well as similar glycan profiles. Compared to 293T-derived recombinant Envs from viruses isolated from chronic HIV-1, transmitted/founder Envs displayed marked differences in their glycosylation site occupancies and in their amounts of complex glycans. Our analysis reveals that the glycosylation patterns of transmitted/founder Envs from two different clades (B and C) are more similar to each other than they are to the glycosylation patterns of chronic HIV-1 Envs derived from their own clades.
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28
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Enzyme digests eliminate nonfunctional Env from HIV-1 particle surfaces, leaving native Env trimers intact and viral infectivity unaffected. J Virol 2011; 85:5825-39. [PMID: 21471242 DOI: 10.1128/jvi.00154-11] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HIV-1 viruses and virus-like particles (VLPs) bear nonnative "junk" forms of envelope (Env) glycoprotein that may undermine the development of antibody responses against functional gp120/gp41 trimers, thereby blunting the ability of particles to elicit neutralizing antibodies. Here, we sought to better understand the nature of junk Env with a view to devising strategies for its removal. Initial studies revealed that native trimers were surprisingly stable in the face of harsh conditions, suggesting that junk Env is unlikely to arise by trimer dissociation or gp120 shedding. Furthermore, the limited gp120 shedding that occurs immediately after synthesis of primary HIV-1 isolate Envs is not caused by aberrant cleavage at the tandem gp120/gp41 cleavage sites, which were found to cleave in a codependent manner. A major VLP contaminant was found to consist of an early, monomeric form of gp160 that is glycosylated in the endoplasmic reticulum (gp160ER) and then bypasses protein maturation and traffics directly into particles. gp160ER was found to bind two copies of monoclonal antibody (MAb) 2G12, consistent with its exclusively high-mannose glycan profile. These findings prompted us to evaluate enzyme digests as a way to remove aberrant Env. Remarkably, sequential glycosidase-protease digests led to a complete or near-complete removal of junk Env from many viral strains, leaving trimers and viral infectivity largely intact. "Trimer VLPs" may be useful neutralizing antibody immunogens.
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29
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Pashov A, Garimalla S, Monzavi-Karbassi B, Kieber-Emmons T. Carbohydrate targets in HIV vaccine research: lessons from failures. Immunotherapy 2011; 1:777-94. [PMID: 20636023 DOI: 10.2217/imt.09.44] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Learning from the successes of other vaccines that enhance natural and existing protective responses to pathogens, the current effort in HIV vaccine research is directed toward inducing cytotoxic responses. Nevertheless, antibodies are fundamental players in vaccine development and are still considered in the context of passive specific immunotherapy of HIV, especially since several broadly neutralizing monoclonals are available. Special interest is directed toward antibodies binding to the glycan array on gp120 since they have the potential of broader reactivity and cross-clade neutralizing capacity. Humoral responses to carbohydrate antigens have proven effective against other pathogens, why not HIV? The variability of the epitope targets on HIV may not be the only problem to developing active or passive immunotherapeutic strategies. The dynamics of the infected immune system leads to ambiguous effects of most of the effector mechanisms calling for new approaches; some may already be available, while others are in the making.
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Affiliation(s)
- Anastas Pashov
- Department of Pathology & Winthrop P Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, 4301 West Markham St, #824 Little Rock, AR 72205, USA
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30
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Kong L, Sheppard NC, Stewart-Jones GBE, Robson CL, Chen H, Xu X, Krashias G, Bonomelli C, Scanlan CN, Kwong PD, Jeffs SA, Jones IM, Sattentau QJ. Expression-system-dependent modulation of HIV-1 envelope glycoprotein antigenicity and immunogenicity. J Mol Biol 2010; 403:131-147. [PMID: 20800070 PMCID: PMC2950005 DOI: 10.1016/j.jmb.2010.08.033] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2010] [Revised: 08/13/2010] [Accepted: 08/17/2010] [Indexed: 12/19/2022]
Abstract
Recombinant expression systems differ in the type of glycosylation they impart on expressed antigens such as the human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins, potentially affecting their biological properties. We performed head-to-head antigenic, immunogenic and molecular profiling of two distantly related Env surface (gp120) antigens produced in different systems: (a) mammalian (293 FreeStyle cells; 293F) cells in the presence of kifunensine, which impart only high-mannose glycans; (b) insect cells (Spodoptera frugiperda, Sf9), which confer mainly paucimannosidic glycans; (c) Sf9 cells recombinant for mammalian glycosylation enzymes (Sf9 Mimic), which impart high-mannose, hybrid and complex glycans without sialic acid; and (d) 293F cells, which impart high-mannose, hybrid and complex glycans with sialic acid. Molecular models revealed a significant difference in gp120 glycan coverage between the Sf9-derived and wild-type mammalian-cell-derived material that is predicted to affect ligand binding sites proximal to glycans. Modeling of solvent-exposed surface electrostatic potentials showed that sialic acid imparts a significant negative surface charge that may influence gp120 antigenicity and immunogenicity. Gp120 expressed in systems that do not incorporate sialic acid displayed increased ligand binding to the CD4 binding and CD4-induced sites compared to those expressed in the system that do, and imparted other more subtle differences in antigenicity in a gp120 subtype-specific manner. Non-sialic-acid-containing gp120 was significantly more immunogenic than the sialylated version when administered in two different adjuvants, and induced higher titers of antibodies competing for CD4 binding site ligand-gp120 interaction. These findings suggest that non-sialic-acid-imparting systems yield gp120 immunogens with modified antigenic and immunogenic properties, considerations that should be considered when selecting expression systems for glycosylated antigens to be used for structure-function studies and for vaccine use.
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Affiliation(s)
- Leopold Kong
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK; Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Neil C Sheppard
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Guillaume B E Stewart-Jones
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Headington, Oxford, OX3 7BN, UK
| | - Cynthia L Robson
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Hongying Chen
- School of Biological Sciences, University of Reading, Reading RG6 6UR, UK
| | - Xiaodong Xu
- School of Biological Sciences, University of Reading, Reading RG6 6UR, UK
| | - George Krashias
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Camille Bonomelli
- Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Christopher N Scanlan
- Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Simon A Jeffs
- Wright-Fleming Institute, Division of Medicine, Imperial College London, Norfolk Place, London, W2 1PG, UK
| | - Ian M Jones
- School of Biological Sciences, University of Reading, Reading RG6 6UR, UK
| | - Quentin J Sattentau
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK.
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31
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Preparation of glycopolymer hollow particles by sacrificial dissolution of colloidal templates. Colloids Surf A Physicochem Eng Asp 2010. [DOI: 10.1016/j.colsurfa.2010.08.030] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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32
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Raska M, Takahashi K, Czernekova L, Zachova K, Hall S, Moldoveanu Z, Elliott MC, Wilson L, Brown R, Jancova D, Barnes S, Vrbkova J, Tomana M, Smith PD, Mestecky J, Renfrow MB, Novak J. Glycosylation patterns of HIV-1 gp120 depend on the type of expressing cells and affect antibody recognition. J Biol Chem 2010; 285:20860-9. [PMID: 20439465 PMCID: PMC2898351 DOI: 10.1074/jbc.m109.085472] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 04/28/2010] [Indexed: 01/18/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) entry is mediated by the interaction between a variably glycosylated envelope glycoprotein (gp120) and host-cell receptors. Approximately half of the molecular mass of gp120 is contributed by N-glycans, which serve as potential epitopes and may shield gp120 from immune recognition. The role of gp120 glycans in the host immune response to HIV-1 has not been comprehensively studied at the molecular level. We developed a new approach to characterize cell-specific gp120 glycosylation, the regulation of glycosylation, and the effect of variable glycosylation on antibody reactivity. A model oligomeric gp120 was expressed in different cell types, including cell lines that represent host-infected cells or cells used to produce gp120 for vaccination purposes. N-Glycosylation of gp120 varied, depending on the cell type used for its expression and the metabolic manipulation during expression. The resultant glycosylation included changes in the ratio of high-mannose to complex N-glycans, terminal decoration, and branching. Differential glycosylation of gp120 affected envelope recognition by polyclonal antibodies from the sera of HIV-1-infected subjects. These results indicate that gp120 glycans contribute to antibody reactivity and should be considered in HIV-1 vaccine design.
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Affiliation(s)
- Milan Raska
- From the Departments of Immunology and
- the Departments of Microbiology
| | | | | | | | | | | | | | | | | | | | | | - Jana Vrbkova
- Mathematical Analysis and Applications of Mathematics, Palacky University in Olomouc, Olomouc 77100, Czech Republic
| | | | - Phillip D. Smith
- Medicine, and
- the Veterans Affairs Medical Center, Birmingham, Alabama 35205, and
| | - Jiri Mestecky
- the Departments of Microbiology
- Medicine, and
- the Institute of Microbiology and Immunology, First Faculty of Medicine, Charles University, Prague, Czech Republic 12108
| | - Matthew B. Renfrow
- Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama 35294
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33
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Binley JM, Ban YEA, Crooks ET, Eggink D, Osawa K, Schief WR, Sanders RW. Role of complex carbohydrates in human immunodeficiency virus type 1 infection and resistance to antibody neutralization. J Virol 2010; 84:5637-55. [PMID: 20335257 PMCID: PMC2876609 DOI: 10.1128/jvi.00105-10] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Accepted: 03/15/2010] [Indexed: 11/20/2022] Open
Abstract
Complex N-glycans flank the receptor binding sites of the outer domain of HIV-1 gp120, ostensibly forming a protective "fence" against antibodies. Here, we investigated the effects of rebuilding this fence with smaller glycoforms by expressing HIV-1 pseudovirions from a primary isolate in a human cell line lacking N-acetylglucosamine transferase I (GnTI), the enzyme that initiates the conversion of oligomannose N-glycans into complex N-glycans. Thus, complex glycans, including those that surround the receptor binding sites, are replaced by fully trimmed oligomannose stumps. Conversely, the untrimmed oligomannoses of the silent domain of gp120 are likely to remain unchanged. For comparison, we produced a mutant virus lacking a complex N-glycan of the V3 loop (N301Q). Both variants exhibited increased sensitivities to V3 loop-specific monoclonal antibodies (MAbs) and soluble CD4. The N301Q virus was also sensitive to "nonneutralizing" MAbs targeting the primary and secondary receptor binding sites. Endoglycosidase H treatment resulted in the removal of outer domain glycans from the GnTI- but not the parent Env trimers, and this was associated with a rapid and complete loss in infectivity. Nevertheless, the glycan-depleted trimers could still bind to soluble receptor and coreceptor analogs, suggesting a block in post-receptor binding conformational changes necessary for fusion. Collectively, our data show that the antennae of complex N-glycans serve to protect the V3 loop and CD4 binding site, while N-glycan stems regulate native trimer conformation, such that their removal can lead to global changes in neutralization sensitivity and, in extreme cases, an inability to complete the conformational rearrangements necessary for infection.
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Affiliation(s)
- James M Binley
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121, USA.
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34
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Two N-linked glycosylation sites in the V2 and C2 regions of human immunodeficiency virus type 1 CRF01_AE envelope glycoprotein gp120 regulate viral neutralization susceptibility to the human monoclonal antibody specific for the CD4 binding domain. J Virol 2010; 84:4311-20. [PMID: 20164234 DOI: 10.1128/jvi.02619-09] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
A recombinant human monoclonal antibody, IgG1 b12 (b12), recognizes a conformational epitope on human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) gp120 that overlaps the CD4 binding domain. Although b12 is able to broadly neutralize HIV-1 subtype B, C, and D viruses, many HIV-1 CRF01_AE viruses are resistant to b12-mediated neutralization. In this report, we examined the molecular mechanisms underlying the low neutralization susceptibility of CRF01_AE viruses to b12, using recently established CRF01_AE Env recombinant viruses. Our results showed that two potential N-linked glycosylation (PNLG) sites in the V2 and C2 regions of Env gp120 played an important role in regulating the susceptibility of CRF01_AE Env to b12. The locations of these PNLG sites correspond to amino acid positions 186 and 197 in HXB2 Env gp120; thus, they are designated N186 and N197 in this study. Removal of N186 significantly conferred the b12 susceptibility of 2 resistant CRF01_AE Env clones, 65CC4 and 107CC2, while the introduction of N186 reduced the b12 susceptibility of a susceptible CRF01_AE Env clone, 65CC1. In addition, removal of both N186 and N197 conferred the b12 susceptibility of 3 resistant CRF01_AE Env clones, 45PB1, 62PL1, and 101PL1, whereas the removal of either N186 or N197 was not sufficient to confer the b12 susceptibility of these CRF01_AE Env clones. Finally, removal of N197 conferred the b12 susceptibility of 2 resistant CRF01_AE Env clones lacking N186, 55PL1 and 102CC2. Taken together, we propose that two PNLG sites, N186 and N197, in Env gp120 are important determinants of the b12 resistance of CRF01_AE viruses.
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Martínez-Avila O, Hijazi K, Marradi M, Clavel C, Campion C, Kelly C, Penadés S. Gold manno-glyconanoparticles: multivalent systems to block HIV-1 gp120 binding to the lectin DC-SIGN. Chemistry 2010; 15:9874-88. [PMID: 19681073 DOI: 10.1002/chem.200900923] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The HIV envelope glycoprotein gp120 takes advantage of the high-mannose clusters on its surface to target the C-type lectin dendritic cell-specific intracellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) on dendritic cells. Mimicking the cluster presentation of oligomannosides on the virus surface is a strategy for designing carbohydrate-based antiviral agents. Bio-inspired by the cluster presentation of gp120, we have designed and prepared a small library of multivalent water-soluble gold glyconanoparticles (manno-GNPs) presenting truncated (oligo)mannosides of the high-mannose undecasaccharide Man(9)GlcNAc(2) and have tested them as inhibitors of DC-SIGN binding to gp120. These glyconanoparticles are ligands for DC-SIGN, which also interacts in the early steps of infection with a large number of pathogens through specific recognition of associated glycans. (Oligo)mannosides endowed with different spacers ending in thiol groups, which enable attachment of the glycoconjugates to the gold surface, have been prepared. manno-GNPs with different spacers and variable density of mannose (oligo)saccharides have been obtained and characterized. Surface plasmon resonance (SPR) experiments with selected manno-GNPs have been performed to study their inhibition potency towards DC-SIGN binding to gp120. The tested manno-GNPs completely inhibit the binding from the micro- to the nanomolar range, while the corresponding monovalent mannosides require millimolar concentrations. manno-GNPs containing the disaccharide Manalpha1-2Manalpha are the best inhibitors, showing more than 20 000-fold increased activity (100 % inhibition at 115 nM) compared to the corresponding monomeric disaccharide (100 % inhibition at 2.2 mM). Furthermore, increasing the density of dimannoside on the gold platform from 50 to 100 % does not improve the level of inhibition.
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Affiliation(s)
- Olga Martínez-Avila
- Laboratory of GlycoNanotechnology, Biofunctional Nanomaterial Unit, CIC biomaGUNE and CIBER-BBN, Parque Tecnológico, San Sebastián, Spain
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36
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Tian Y, Zhang H. Glycoproteomics and clinical applications. Proteomics Clin Appl 2009; 4:124-32. [PMID: 21137038 DOI: 10.1002/prca.200900161] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 10/27/2009] [Accepted: 11/05/2009] [Indexed: 11/11/2022]
Abstract
Glycosylation is the most structurally complicated and diverse type of protein modifications. Protein glycosylation has long been recognized to play fundamental roles in many biological processes, as well as in disease genesis and progression. Glycoproteomics focuses on characterization of proteins modified by carbohydrates. Glycoproteomic studies normally include strategies to enrich glycoproteins containing particular carbohydrate structures from protein mixtures followed by quantitative proteomic analysis. These glycoproteomic studies determine which proteins are glycosylated, the glycosylation sites, the carbohydrate structures, as well as the abundance and function of the glycoproteins in different biological and pathological processes. Here we review the recent development in methods used in glycoproteomic analysis. These techniques are essential in elucidation of the relationships between protein glycosylation and disease states. We also review the clinical applications of different glycoproteomic methods.
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Affiliation(s)
- Yuan Tian
- Department of Pathology, Johns Hopkins University, Baltimore, MD, USA
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37
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Kim YG, Moon S, Kuritzkes DR, Demirci U. Quantum dot-based HIV capture and imaging in a microfluidic channel. Biosens Bioelectron 2009; 25:253-8. [PMID: 19665685 PMCID: PMC2746625 DOI: 10.1016/j.bios.2009.06.023] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 06/01/2009] [Accepted: 06/11/2009] [Indexed: 11/30/2022]
Abstract
Globally, over 33.2 million people who mostly live in developing countries with limited access to the appropriate medical care suffer from the human immunodeficiency virus (HIV) infection. We developed an on-chip HIV capture and imaging method using quantum dots (Qdots) from fingerprick volume (10 microl) of unprocessed HIV-infected patient whole blood in anti-gp120 antibody-immobilized microfluidic chip. Two-color Qdots (Qdot525 and Qdot655 streptavidin conjugates) were used to identify the captured HIV by simultaneous labeling the envelope gp120 glycoprotein and its high-mannose glycans. This dual-stain imaging technique using Qdots provides a new and effective tool for accurate identification of HIV particles from patient whole blood without any pre-processing. This on-chip HIV capture and imaging platform creates new avenues for point-of-care diagnostics and monitoring applications of infectious diseases.
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Affiliation(s)
- Yun-Gon Kim
- Bio-Acoustic MEMS in Medicine Laboratory, Center for Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139
| | - Sangjun Moon
- Bio-Acoustic MEMS in Medicine Laboratory, Center for Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139
| | - Daniel R. Kuritzkes
- Section of Retroviral Therapeutics, Brigham and Women's Hospital, Boston, MA 02115
| | - Utkan Demirci
- Bio-Acoustic MEMS in Medicine Laboratory, Center for Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139
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38
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Go EP, Chang Q, Liao HX, Sutherland LL, Alam SM, Haynes BF, Desaire H. Glycosylation site-specific analysis of clade C HIV-1 envelope proteins. J Proteome Res 2009; 8:4231-42. [PMID: 19610667 PMCID: PMC2756219 DOI: 10.1021/pr9002728] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The extensive glycosylation of HIV-1 envelope proteins (Envs), gp120/gp41, is known to play an important role in evasion of host immune response by masking key neutralization epitopes and presenting the Env glycosylation as "self" to the host immune system. The Env glycosylation is mostly conserved but continues to evolve to modulate viral infectivity. Thus, profiling Env glycosylation and distinguishing interclade and intraclade glycosylation variations are necessary components in unraveling the effects of glycosylation on Env's immunogenicity. Here, we describe a mass spectrometry-based approach to characterize the glycosylation profiles of two rVV-expressed clade C Envs by identifying the glycan motifs on each glycosylation site and determining the degree of glycosylation site occupancy. One Env is a wild-type Env, while the other is a synthetic "consensus" Env (C.CON). The observed differences in the glycosylation profiles between the two clade C Envs show that C.CON has more unutilized sites and high levels of high mannose glycans; these features mimic the glycosylation profile of a Group M consensus immunogen, CON-S. Our results also reveal a clade-specific glycosylation pattern. Discerning interclade and intraclade glycosylation variations could provide valuable information in understanding the molecular differences among the different HIV-1 clades and in designing new Env-based immunogens.
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Affiliation(s)
- Eden P. Go
- Department of Chemistry, University of Kansas, Lawrence, KS, 66045
| | - Qing Chang
- Department of Chemistry, University of Kansas, Lawrence, KS, 66045
| | - Hua-Xin Liao
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 22270
| | - Laura L. Sutherland
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 22270
| | - S. Munir Alam
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 22270
| | - Barton F. Haynes
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 22270
| | - Heather Desaire
- Department of Chemistry, University of Kansas, Lawrence, KS, 66045
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Surface modification of polymer latex particles by AGET ATRP of a styrene derivative bearing a lactose residue. Colloids Surf B Biointerfaces 2009; 71:194-9. [DOI: 10.1016/j.colsurfb.2009.02.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Accepted: 02/10/2009] [Indexed: 11/20/2022]
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Abstract
Galectins, which were first characterized in the mid-1970s, were assigned a role in the recognition of endogenous ('self') carbohydrate ligands in embryogenesis, development and immune regulation. Recently, however, galectins have been shown to bind glycans on the surface of potentially pathogenic microorganisms, and function as recognition and effector factors in innate immunity. Some parasites subvert the recognition roles of the vector or host galectins to ensure successful attachment or invasion. This Review discusses the role of galectins in microbial infection, with particular emphasis on adaptations of pathogens to evasion or subversion of host galectin-mediated immune responses.
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Affiliation(s)
- Gerardo R Vasta
- University of Maryland Biotechnology Institute, Center of Marine Biotechnology, Columbus Center, Baltimore, 21202, USA.
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41
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Krishnamoorthy L, Bess JW, Preston AB, Nagashima K, Mahal LK. HIV-1 and microvesicles from T cells share a common glycome, arguing for a common origin. Nat Chem Biol 2009; 5:244-50. [PMID: 19234452 PMCID: PMC2713040 DOI: 10.1038/nchembio.151] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Accepted: 02/03/2009] [Indexed: 01/17/2023]
Abstract
HIV-1 is a master at deceiving the immune system and usurping host biosynthetic machinery. Although HIV-1 is coated with host-derived glycoproteins, only glycosylation of viral gp120 has been described. Here we use lectin microarray technology to analyze the glycome of intact HIV-1 virions. We show that the glycan coat of human T cell line-derived HIV-1 matches that of native immunomodulatory microvesicles. The carbohydrate composition of both virus and microvesicles is cell-line dependent, which suggests a mechanism to rapidly camouflage the virus within the host. In addition, binding of both virus and microvesicles to antiviral lectins is enriched over the host cell, raising concern about targeting these glycans for therapeutics. This work also sheds light on the binding of HIV-1 to galectin-1, an important human immune lectin. Overall, our work strongly supports the theory that HIV-1 co-opts the exocytic pathway of microvesicles, thus potentially explaining why eliciting a protective antiviral immune response is difficult.
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Affiliation(s)
- Lakshmi Krishnamoorthy
- Department of Chemistry and Biochemistry, Center for Systems and Synthetic Biology and Institute for Cellular and Molecular Biology, University of Texas at Austin, 1 University Station, A5300, Austin, TX 78712-0265
| | - Julian W. Bess
- AIDS Vaccine Program, SAIC-Frederick, Inc., National Cancer Institute at-Frederick, Frederick, MD 21702-1201
| | - Alex B. Preston
- Department of Chemistry and Biochemistry, Center for Systems and Synthetic Biology and Institute for Cellular and Molecular Biology, University of Texas at Austin, 1 University Station, A5300, Austin, TX 78712-0265
| | - Kunio Nagashima
- Image Analysis Lab, SAIC-Frederick, Inc., National Cancer Institute at-Frederick, Frederick, MD 21702-1201
| | - Lara K. Mahal
- Department of Chemistry and Biochemistry, Center for Systems and Synthetic Biology and Institute for Cellular and Molecular Biology, University of Texas at Austin, 1 University Station, A5300, Austin, TX 78712-0265
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42
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Graham DRM, Mitsak MJ, Elliott ST, Chen D, Whelan SA, Hart GW, Van Eyk JE. Two-dimensional gel-based approaches for the assessment of N-Linked and O-GlcNAc glycosylation in human and simian immunodeficiency viruses. Proteomics 2008; 8:4919-30. [PMID: 19072736 PMCID: PMC2785494 DOI: 10.1002/pmic.200800608] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The glycosylation state of envelope glycoproteins in human and simian immunodeficiency viruses (HIV/SIV) is critical to viral infectivity and tropism, viral protein processing, and in virus evasion of the immune system. Using a rapid fluorescent 2-D gel-based method coupled with enzymatic pre-treatment of virus with PNGase F (Peptide: N-Glycosidase F) and fluorescent 2-D gels or 2-D gel Western blotting, we show significant differences in the glycosylation patterns of two SIV strains widely used in animal models of HIV disease and vaccine studies. We also demonstrate the modification of a host protein important in HIV biology (HLA-DR) by O-GlcNAc. Further, this experimental pipeline allows for the identification of the modified protein and the site of N-linked glycosylation by fluorescent 2-DE coupled with MS and the qualitative and semi-quantitative assessment of viral glycosylation. The method is fully compatible with downstream glycomics analysis. This approach will permit correlation of virus glycosylation status with pathological severity and may serve as a rapid screen of viruses from physiological samples for further study by more advanced MS methodology.
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Affiliation(s)
- David R M Graham
- Department of Medicine, Division of Cardiology, The JHU Bayview Proteomics Center, The Johns Hopkins University, Baltimore, MD 21224, USA.
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43
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Identification of the LWYIK motif located in the human immunodeficiency virus type 1 transmembrane gp41 protein as a distinct determinant for viral infection. J Virol 2008; 83:870-83. [PMID: 18987155 DOI: 10.1128/jvi.01088-08] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The highly conserved LWYIK motif located immediately proximal to the membrane-spanning domain of the gp41 transmembrane protein of human immunodeficiency virus type 1 has been proposed as being important for the surface envelope (Env) glycoprotein's association with lipid rafts and gp41-mediated membrane fusion. Here we employed substitution and deletion mutagenesis to understand the role of this motif in the virus life cycle. None of the mutants examined affected the synthesis, precursor processing, CD4 binding, oligomerization, or cell surface expression of the Env, nor did they alter Env incorporation into the virus. All of the mutants, particularly the DeltaYI, DeltaIK, and DeltaLWYIK mutants, in which the indicated residues were deleted, exhibited greatly reduced one-cycle viral replication and the Env trans-complementation ability. All of these deletion mutant proteins were still localized in the lipid rafts. With the exception of the Trp-to-Ala (WA) mutant, which exhibited reduced viral infectivity albeit with normal membrane fusion, all mutants displayed loss of some or almost all of the membrane fusion ability. Although these deletion mutants partially inhibited in trans wild-type (WT) Env-mediated fusion, they were more effective in dominantly interfering with WT Env-mediated viral entry when coexpressed with the WT Env, implying a role of this motif in postfusion events as well. Both T20 and L43L peptides derived from the two gp41 extracellular C- and N-terminal alpha-helical heptad repeats, respectively, inhibited WT and DeltaLWYIK Env-mediated viral entry with comparable efficacies. Biotin-tagged T20 effectively captured both the fusion-active, prehairpin intermediates of WT and mutant gp41 upon CD4 activation. Env without the deletion of the LWYIK motif still effectively mediated lipid mixing but inhibited content mixing. Our study demonstrates that the immediate membrane-proximal LWYIK motif acts as a unique and distinct determinant located in the gp41 C-terminal ectodomain by promoting enlargement of fusion pores and postfusion activities.
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Irungu J, Go EP, Zhang Y, Dalpathado DS, Liao HX, Haynes BF, Desaire H. Comparison of HPLC/ESI-FTICR MS versus MALDI-TOF/TOF MS for glycopeptide analysis of a highly glycosylated HIV envelope glycoprotein. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2008; 19:1209-20. [PMID: 18565761 PMCID: PMC3706080 DOI: 10.1016/j.jasms.2008.05.010] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2008] [Revised: 05/14/2008] [Accepted: 05/16/2008] [Indexed: 05/11/2023]
Abstract
Defining the structures and locations of the glycans attached on secreted proteins and virus envelope proteins is important in understanding how glycosylation affects their biological properties. Glycopeptide mass spectrometry (MS)-based analysis is a very powerful, emerging approach to characterize glycoproteins, in which glycosylation sites and the corresponding glycan structures are elucidated in a single MS experiment. However, to date there is not a consensus regarding which mass spectrometric platform provides the best glycosylation coverage information. Herein, we employ two of the most widely used MS approaches, online high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC/ESI-MS) and offline HPLC followed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), to determine which of the two approaches provides the best glycosylation coverage information of a complex glycoprotein, the group M consensus HIV-1 envelope, CON-S gp140DeltaCFI, which has 31 potential glycosylation sites. Our results highlight differences in the informational content obtained between the two methods such as the overall number of glycosylation sites detected, the numbers of N-linked glycans present at each site, and the type of confirmatory information obtained about the glycopeptide using MS/MS experiments. The two approaches are quite complementary, both in their coverage of glycopeptides and in the information they provide in MS/MS experiments. The information in this study contributes to the field of mass spectrometry by demonstrating the strengths and limitations of two widely used MS platforms in glycoprotein analysis.
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Affiliation(s)
- Janet Irungu
- Department of Chemistry, University of Kansas, 1251 Wescoe Hall Drive, Lawrence, KS 66045, USA
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45
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Go EP, Irungu J, Zhang Y, Dalpathado DS, Liao HX, Sutherland LL, Alam SM, Haynes BF, Desaire H. Glycosylation site-specific analysis of HIV envelope proteins (JR-FL and CON-S) reveals major differences in glycosylation site occupancy, glycoform profiles, and antigenic epitopes' accessibility. J Proteome Res 2008; 7:1660-74. [PMID: 18330979 DOI: 10.1021/pr7006957] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The HIV-1 envelope (Env) is a key determinant in mediating viral entry and fusion to host cells and is a major target for HIV vaccine development. While Env is typically about 50% glycan by mass, glycosylation sites are known to evolve, with some glycosylation profiles presumably being more effective at facilitating neutralization escape than others. Thus, characterizing glycosylation patterns of Env and native virions and correlating glycosylation profiles with infectivity and Env immunogenicity are necessary first steps in designing effective immunogens. Herein, we describe a mass spectrometry-based strategy to determine HIV-1 Env glycosylation patterns and have compared two mammalian cell expressed recombinant Env immunogens, one a limited immunogen and one that induces cross-clade neutralizing antibodies. We have used a glycopeptide-based mass mapping approach to identify and characterize Env's glycosylation patterns by elucidating which sites are utilized and what type of glycan motif is present at each glycosylation site. Our results show that the immunogens displayed different degrees of glycosylation as well as a different characteristic set of glycan motifs. Thus, these techniques can be used to (1) define glycosylation profiles of recombinant Env proteins and Env on mature virions, (2) define specific carbohydrate moieties at each glycosylation site, and (3) determine the role of certain carbohydrates in HIV-1 infectivity and in modulation of Env immunogenicity.
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Affiliation(s)
- Eden P Go
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA
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46
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47
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Scanlan CN, Offer J, Zitzmann N, Dwek RA. Exploiting the defensive sugars of HIV-1 for drug and vaccine design. Nature 2007; 446:1038-45. [PMID: 17460665 DOI: 10.1038/nature05818] [Citation(s) in RCA: 208] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The sustained effort towards developing an antibody vaccine against HIV/AIDS has provided much of our understanding of viral immunology. It is generally accepted that one of the main barriers to antibody neutralization of HIV is the array of protective structural carbohydrates that covers the antigens on the virus's surface. Intriguingly, however, recent findings suggest that these carbohydrates, which have evolved to protect HIV and promote its transmission, are also attractive therapeutic targets.
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Affiliation(s)
- Christopher N Scanlan
- Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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48
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Fukase K, Nakayama H, Kurosawa M, Ikegaki T, Kanoh T, Hase S, Kusumoto S. Functional Fluorescence Labeling of Carbohydrates and Its Use for Preparation of Neoglycoconjugates. J Carbohydr Chem 2006. [DOI: 10.1080/07328309408011676] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Koichi Fukase
- a Department of Chemistry, Faculty of Science , Osaka University , Toyonaka , Osaka , 560 , Japan
| | - Hideo Nakayama
- a Department of Chemistry, Faculty of Science , Osaka University , Toyonaka , Osaka , 560 , Japan
| | - Motohiro Kurosawa
- a Department of Chemistry, Faculty of Science , Osaka University , Toyonaka , Osaka , 560 , Japan
| | - Toshiki Ikegaki
- a Department of Chemistry, Faculty of Science , Osaka University , Toyonaka , Osaka , 560 , Japan
| | - Takeshi Kanoh
- a Department of Chemistry, Faculty of Science , Osaka University , Toyonaka , Osaka , 560 , Japan
| | - Sumihiro Hase
- a Department of Chemistry, Faculty of Science , Osaka University , Toyonaka , Osaka , 560 , Japan
| | - Shoichi Kusumoto
- a Department of Chemistry, Faculty of Science , Osaka University , Toyonaka , Osaka , 560 , Japan
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49
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Abdel-Motal U, Wang S, Lu S, Wigglesworth K, Galili U. Increased immunogenicity of human immunodeficiency virus gp120 engineered to express Galalpha1-3Galbeta1-4GlcNAc-R epitopes. J Virol 2006; 80:6943-51. [PMID: 16809300 PMCID: PMC1489031 DOI: 10.1128/jvi.00310-06] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The glycan shield comprised of multiple carbohydrate chains on the human immunodeficiency virus (HIV) envelope glycoprotein gp120 helps the virus to evade neutralizing antibodies. The present study describes a novel method for increasing immunogenicity of gp120 vaccine by enzymatic replacement of sialic acid on these carbohydrate chains with Galalpha1-3Galbeta1-4GlcNAc-R (alpha-gal) epitopes. These epitopes are ligands for the natural anti-Gal antibody constituting approximately 1% of immunoglobulin G in humans. We hypothesize that vaccination with gp120 expressing alpha-gal epitopes (gp120(alphagal)) results in in vivo formation of immune complexes with anti-Gal, which targets vaccines for effective uptake by antigen-presenting cells (APC), due to interaction between the Fc portion of the antibody and Fcgamma receptors on APC. This in turn results in effective transport of the vaccine to lymph nodes and effective processing and presentation of gp120 immunogenic peptides by APC for eliciting a strong anti-gp120 immune response. This hypothesis was tested in alpha-1,3-galactosyltransferase knockout mice, which produce anti-Gal. Mice immunized with gp120(alphagal) produced anti-gp120 antibodies in titers that were >100-fold higher than those measured in mice immunized with comparable amounts of gp120 and effectively neutralized HIV. T-cell response, measured by ELISPOT, was much higher in mice immunized with gp120(alphagal) than in mice immunized with gp120. It is suggested that gp120(alphagal) can serve as a platform for anti-Gal-mediated targeting of additional vaccinating HIV proteins fused to gp120(alphagal), thereby creating effective prophylactic vaccines.
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Affiliation(s)
- Ussama Abdel-Motal
- Department of Medicine, University of Massachusetts Medical School, 364 Plantation Street, LRB, Worcester, 01605, USA
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50
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Pashov AD, Plaxco J, Kaveri SV, Monzavi-Karbassi B, Harn D, Kieber-Emmons T. Multiple antigenic mimotopes of HIV carbohydrate antigens: relating structure and antigenicity. J Biol Chem 2006; 281:29675-83. [PMID: 16899462 DOI: 10.1074/jbc.m604137200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Carbohydrate mimetic peptides are designable, and they can carry T-cell epitopes and circumvent tolerance. A mimic-based human immunodeficiency virus (HIV) vaccine can be a viable alternative to carbohydrate-based antigens if the diversity of epitopes found on gp120 can be recapitulated. To improve existing mimics, an attempt was made to study the structural correlates of the observed polyspecificity of carbohydrate mimetic peptides based on the Y(P/R)Y motif in more detail. A carbohydrate mimetic peptide, D002 (RGGLCYCRYRYCVCVGR), bound a number of lectins with different specificities. Although this peptide reacted strongly with both lotus and concanavalin A (ConA) lectins, it bound to lotus stronger than ConA. By varying the central motif RYRY, five versions were produced in multiple antigen peptide format, and their avidity for lotus and ConA lectins was tested by surface plasmon resonance. Although the kinetic parameters were similar, the version based on the sequence YPYRY had an optimal affinity for both lectins as well as improved avidity for wheat germ agglutinin and phytohemagglutinin. Thus, as far as lectin specificity is concerned, YPYRY had improved multiple antigenic properties. Both RYRY and YPYRY precipitated antibodies from human IgG for intravenous use that bound to gp120 in vitro and immunoprecipitated gp120 from transfected CHO-PI cells. Thus, Y(P/R)Y motifs mimic multiple carbohydrate epitopes, many of which are found on HIV, and preimmune human IgG antibodies that bind to HIV carbohydrates cross-react to a comparable extent with both RYRY and YPYRY carbohydrate mimetic peptides.
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Affiliation(s)
- Anastas D Pashov
- Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
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