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Zhong Q, Xiao X, Qiu Y, Xu Z, Chen C, Chong B, Zhao X, Hai S, Li S, An Z, Dai L. Protein posttranslational modifications in health and diseases: Functions, regulatory mechanisms, and therapeutic implications. MedComm (Beijing) 2023; 4:e261. [PMID: 37143582 PMCID: PMC10152985 DOI: 10.1002/mco2.261] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 03/26/2023] [Accepted: 03/27/2023] [Indexed: 05/06/2023] Open
Abstract
Protein posttranslational modifications (PTMs) refer to the breaking or generation of covalent bonds on the backbones or amino acid side chains of proteins and expand the diversity of proteins, which provides the basis for the emergence of organismal complexity. To date, more than 650 types of protein modifications, such as the most well-known phosphorylation, ubiquitination, glycosylation, methylation, SUMOylation, short-chain and long-chain acylation modifications, redox modifications, and irreversible modifications, have been described, and the inventory is still increasing. By changing the protein conformation, localization, activity, stability, charges, and interactions with other biomolecules, PTMs ultimately alter the phenotypes and biological processes of cells. The homeostasis of protein modifications is important to human health. Abnormal PTMs may cause changes in protein properties and loss of protein functions, which are closely related to the occurrence and development of various diseases. In this review, we systematically introduce the characteristics, regulatory mechanisms, and functions of various PTMs in health and diseases. In addition, the therapeutic prospects in various diseases by targeting PTMs and associated regulatory enzymes are also summarized. This work will deepen the understanding of protein modifications in health and diseases and promote the discovery of diagnostic and prognostic markers and drug targets for diseases.
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Affiliation(s)
- Qian Zhong
- Department of Endocrinology and MetabolismGeneral Practice Ward/International Medical Center WardGeneral Practice Medical Center and National Clinical Research Center for GeriatricsState Key Laboratory of BiotherapyWest China Hospital, Sichuan UniversityChengduChina
| | - Xina Xiao
- Department of Endocrinology and MetabolismGeneral Practice Ward/International Medical Center WardGeneral Practice Medical Center and National Clinical Research Center for GeriatricsState Key Laboratory of BiotherapyWest China Hospital, Sichuan UniversityChengduChina
| | - Yijie Qiu
- Department of Endocrinology and MetabolismGeneral Practice Ward/International Medical Center WardGeneral Practice Medical Center and National Clinical Research Center for GeriatricsState Key Laboratory of BiotherapyWest China Hospital, Sichuan UniversityChengduChina
| | - Zhiqiang Xu
- Department of Endocrinology and MetabolismGeneral Practice Ward/International Medical Center WardGeneral Practice Medical Center and National Clinical Research Center for GeriatricsState Key Laboratory of BiotherapyWest China Hospital, Sichuan UniversityChengduChina
| | - Chunyu Chen
- Department of Endocrinology and MetabolismGeneral Practice Ward/International Medical Center WardGeneral Practice Medical Center and National Clinical Research Center for GeriatricsState Key Laboratory of BiotherapyWest China Hospital, Sichuan UniversityChengduChina
| | - Baochen Chong
- Department of Endocrinology and MetabolismGeneral Practice Ward/International Medical Center WardGeneral Practice Medical Center and National Clinical Research Center for GeriatricsState Key Laboratory of BiotherapyWest China Hospital, Sichuan UniversityChengduChina
| | - Xinjun Zhao
- Department of Endocrinology and MetabolismGeneral Practice Ward/International Medical Center WardGeneral Practice Medical Center and National Clinical Research Center for GeriatricsState Key Laboratory of BiotherapyWest China Hospital, Sichuan UniversityChengduChina
| | - Shan Hai
- Department of Endocrinology and MetabolismGeneral Practice Ward/International Medical Center WardGeneral Practice Medical Center and National Clinical Research Center for GeriatricsState Key Laboratory of BiotherapyWest China Hospital, Sichuan UniversityChengduChina
| | - Shuangqing Li
- Department of Endocrinology and MetabolismGeneral Practice Ward/International Medical Center WardGeneral Practice Medical Center and National Clinical Research Center for GeriatricsState Key Laboratory of BiotherapyWest China Hospital, Sichuan UniversityChengduChina
| | - Zhenmei An
- Department of Endocrinology and MetabolismGeneral Practice Ward/International Medical Center WardGeneral Practice Medical Center and National Clinical Research Center for GeriatricsState Key Laboratory of BiotherapyWest China Hospital, Sichuan UniversityChengduChina
| | - Lunzhi Dai
- Department of Endocrinology and MetabolismGeneral Practice Ward/International Medical Center WardGeneral Practice Medical Center and National Clinical Research Center for GeriatricsState Key Laboratory of BiotherapyWest China Hospital, Sichuan UniversityChengduChina
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Lee SH, No JS, Kim K, Budhathoki S, Park K, Lee GY, Cho S, Kim BH, Cho S, Kim J, Lee J, Cho SH, Kim HC, Klein TA, Uhm CS, Kim WK, Song JW. Novel Paju Apodemus paramyxovirus 1 and 2, harbored by Apodemus agrarius in the Republic of Korea. Virology 2021; 562:40-49. [PMID: 34256243 DOI: 10.1016/j.virol.2021.06.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/29/2021] [Accepted: 06/30/2021] [Indexed: 01/19/2023]
Abstract
Paramyxoviruses harbored by multiple natural reservoirs pose a potential threat to public health. Jeilongvirus has been proposed as a novel paramyxovirus genus found in rodents, bats, and cats. Paramyxovirus RNA was detected in 108/824 (13.1%) Apodemus agrarius captured at 14 trapping sites in the Republic of Korea. We first present two genetically distinct novel paramyxoviruses, Paju Apodemus paramyxovirus 1 (PAPV-1) and 2 (PAPV-2). The disparity between PAPV-1 (19,716 nucleotides) and -2 (17,475 nucleotides) revealed the presence of the SH gene and length of the G gene in the genome organization. The phylogeny of PAPV-1 and -2 belonged to distinct genetic lineages of Jeilongvirus, respectively, even though these viruses were originated from A. agrarius. PAPV-1 infected human epithelial and endothelial cells, facilitating the induction of type I/III interferons, interferon-stimulated genes, and pro-inflammatory cytokines. Therefore, this study provides insights into the molecular epidemiology, genetic diversity, and virus-host interactions of novel rodent-borne paramyxoviruses.
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Affiliation(s)
- Seung-Ho Lee
- Department of Microbiology, Korea University College of Medicine, Seoul, Republic of Korea
| | - Jin Sun No
- Department of Microbiology, Korea University College of Medicine, Seoul, Republic of Korea
| | - Kijin Kim
- Department of Microbiology, Korea University College of Medicine, Seoul, Republic of Korea
| | - Shailesh Budhathoki
- Department of Microbiology, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Kyungmin Park
- Department of Microbiology, Korea University College of Medicine, Seoul, Republic of Korea; BK21 Graduate Program, Department of Biomedical Sciences, Korea University College of Medicine, Seoul, Republic of Korea
| | - Geum-Young Lee
- Department of Microbiology, Korea University College of Medicine, Seoul, Republic of Korea
| | - Seungchan Cho
- Department of Microbiology, Korea University College of Medicine, Seoul, Republic of Korea
| | | | | | - Jongwoo Kim
- Department of Microbiology, Korea University College of Medicine, Seoul, Republic of Korea
| | - Jingyeong Lee
- Department of Microbiology, Korea University College of Medicine, Seoul, Republic of Korea
| | - Seung Hye Cho
- Department of Biomedical Science, College of Natural Sciences, Hallym University, Chuncheon, Republic of Korea
| | - Heung-Chul Kim
- Force Health Protection and Preventive Medicine, Medical Department Activity-Korea/65th, Medical Brigade, Unit 15281, APO AP, 96271-5281, USA
| | - Terry A Klein
- Force Health Protection and Preventive Medicine, Medical Department Activity-Korea/65th, Medical Brigade, Unit 15281, APO AP, 96271-5281, USA
| | - Chang-Sub Uhm
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Won-Keun Kim
- Department of Microbiology, College of Medicine, Hallym University, Chuncheon, Republic of Korea; Institute of Medical Science, College of Medicine, Hallym University, Chuncheon, Republic of Korea.
| | - Jin-Won Song
- Department of Microbiology, Korea University College of Medicine, Seoul, Republic of Korea; BK21 Graduate Program, Department of Biomedical Sciences, Korea University College of Medicine, Seoul, Republic of Korea.
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Bruxelle JF, Trattnig N, Mureithi MW, Landais E, Pantophlet R. HIV-1 Entry and Prospects for Protecting against Infection. Microorganisms 2021; 9:microorganisms9020228. [PMID: 33499233 PMCID: PMC7911371 DOI: 10.3390/microorganisms9020228] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 12/19/2022] Open
Abstract
Human Immunodeficiency Virus type-1 (HIV-1) establishes a latent viral reservoir soon after infection, which poses a major challenge for drug treatment and curative strategies. Many efforts are therefore focused on blocking infection. To this end, both viral and host factors relevant to the onset of infection need to be considered. Given that HIV-1 is most often transmitted mucosally, strategies designed to protect against infection need to be effective at mucosal portals of entry. These strategies need to contend also with cell-free and cell-associated transmitted/founder (T/F) virus forms; both can initiate and establish infection. This review will discuss how insight from the current model of HIV-1 mucosal transmission and cell entry has highlighted challenges in developing effective strategies to prevent infection. First, we examine key viral and host factors that play a role in transmission and infection. We then discuss preventive strategies based on antibody-mediated protection, with emphasis on targeting T/F viruses and mucosal immunity. Lastly, we review treatment strategies targeting viral entry, with focus on the most clinically advanced entry inhibitors.
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Affiliation(s)
- Jean-François Bruxelle
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- Correspondence: (J.-F.B.); (R.P.)
| | - Nino Trattnig
- Chemical Biology and Drug Discovery, Utrecht University, 3584 CG Utrecht, The Netherlands;
| | - Marianne W. Mureithi
- KAVI—Institute of Clinical Research, College of Health Sciences, University of Nairobi, P.O. Box, Nairobi 19676–00202, Kenya;
| | - Elise Landais
- IAVI Neutralizing Antibody Center, La Jolla, CA 92037, USA;
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA 92037, USA
| | - Ralph Pantophlet
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- Correspondence: (J.-F.B.); (R.P.)
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Zhang XL, Qu H. The Role of Glycosylation in Infectious Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1325:219-237. [PMID: 34495538 DOI: 10.1007/978-3-030-70115-4_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Glycosylation plays an important role in infectious diseases. Many important interactions between pathogens and hosts involve their carbohydrate structures (glycans). Glycan interactions can mediate adhesion, recognition, invasion, and immune evasion of pathogens. To date, changes in many protein N/O-linked glycosylation have been identified as biomarkers for the development of infectious diseases and cancers. In this review, we will discuss the principal findings and the roles of glycosylation of both pathogens and host cells in the context of human important infectious diseases. Understanding the role and mechanism of glycan-lectin interaction between pathogens and hosts may create a new paradigm for discovering novel glycan-based therapies that can lead to eradication or functional cure of pathogens infection.
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Affiliation(s)
- Xiao-Lian Zhang
- State Key Laboratory of Virology, Hubei Province Key Laboratory of Allergy and Immunology, Department of Immunology, Wuhan University School of Basic Medical Sciences, Wuhan, China.
| | - Haoran Qu
- State Key Laboratory of Virology, Hubei Province Key Laboratory of Allergy and Immunology, Department of Immunology, Wuhan University School of Basic Medical Sciences, Wuhan, China
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Narasimhulu VGS, Bellamy-McIntyre AK, Laumaea AE, Lay CS, Harrison DN, King HAD, Drummer HE, Poumbourios P. Distinct functions for the membrane-proximal ectodomain region (MPER) of HIV-1 gp41 in cell-free and cell-cell viral transmission and cell-cell fusion. J Biol Chem 2018; 293:6099-6120. [PMID: 29496992 DOI: 10.1074/jbc.ra117.000537] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 02/21/2018] [Indexed: 11/06/2022] Open
Abstract
HIV-1 is spread by cell-free virions and by cell-cell viral transfer. We asked whether the structure and function of a broad neutralizing antibody (bNAb) epitope, the membrane-proximal ectodomain region (MPER) of the viral gp41 transmembrane glycoprotein, differ in cell-free and cell-cell-transmitted viruses and whether this difference could be related to Ab neutralization sensitivity. Whereas cell-free viruses bearing W666A and I675A substitutions in the MPER lacked infectivity, cell-associated mutant viruses were able to initiate robust spreading infection. Infectivity was restored to cell-free viruses by additional substitutions in the cytoplasmic tail (CT) of gp41 known to disrupt interactions with the viral matrix protein. We observed contrasting effects on cell-free virus infectivity when W666A was introduced to two transmitted/founder isolates, but both mutants could still mediate cell-cell spread. Domain swapping indicated that the disparate W666A phenotypes of the cell-free transmitted/founder viruses are controlled by sequences in variable regions 1, 2, and 4 of gp120. The sequential passaging of an MPER mutant (W672A) in peripheral blood mononuclear cells enabled selection of viral revertants with loss-of-glycan suppressor mutations in variable region 1, suggesting a functional interaction between variable region 1 and the MPER. An MPER-directed bNAb neutralized cell-free virus but not cell-cell viral spread. Our results suggest that the MPER of cell-cell-transmitted virions has a malleable structure that tolerates mutagenic disruption but is not accessible to bNAbs. In cell-free virions, interactions mediated by the CT impose an alternative MPER structure that is less tolerant of mutagenic alteration and is efficiently targeted by bNAbs.
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Affiliation(s)
- Vani G S Narasimhulu
- From the Virus Entry and Vaccines Laboratory, Burnet Institute, Melbourne, Victoria 3004.,the Department of Microbiology and Immunology at the Peter Doherty Institute, University of Melbourne, Parkville, Victoria 3010, and
| | - Anna K Bellamy-McIntyre
- From the Virus Entry and Vaccines Laboratory, Burnet Institute, Melbourne, Victoria 3004.,the Departments of Microbiology and
| | - Annamarie E Laumaea
- From the Virus Entry and Vaccines Laboratory, Burnet Institute, Melbourne, Victoria 3004.,the Department of Microbiology and Immunology at the Peter Doherty Institute, University of Melbourne, Parkville, Victoria 3010, and
| | - Chan-Sien Lay
- Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - David N Harrison
- From the Virus Entry and Vaccines Laboratory, Burnet Institute, Melbourne, Victoria 3004
| | - Hannah A D King
- From the Virus Entry and Vaccines Laboratory, Burnet Institute, Melbourne, Victoria 3004.,the Department of Microbiology and Immunology at the Peter Doherty Institute, University of Melbourne, Parkville, Victoria 3010, and
| | - Heidi E Drummer
- From the Virus Entry and Vaccines Laboratory, Burnet Institute, Melbourne, Victoria 3004.,the Department of Microbiology and Immunology at the Peter Doherty Institute, University of Melbourne, Parkville, Victoria 3010, and.,the Departments of Microbiology and
| | - Pantelis Poumbourios
- From the Virus Entry and Vaccines Laboratory, Burnet Institute, Melbourne, Victoria 3004, .,the Departments of Microbiology and.,Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
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Identification of Novel Structural Determinants in MW965 Env That Regulate the Neutralization Phenotype and Conformational Masking Potential of Primary HIV-1 Isolates. J Virol 2018; 92:JVI.01779-17. [PMID: 29237828 DOI: 10.1128/jvi.01779-17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 11/28/2017] [Indexed: 11/20/2022] Open
Abstract
The subtype C HIV-1 isolate MW965.26 is a highly neutralization-sensitive tier 1a primary isolate that is widely used in vaccine studies, but the basis for the sensitive neutralization phenotype of this isolate is not known. Substituting the MW965.26 V1/V2 domain into a neutralization-sensitive SF162 Env clone resulted in high resistance to standard anti-V3 monoclonal antibodies, demonstrating that this region possesses strong masking activity in a standard Env backbone and indicating that determinants elsewhere in MW965.26 Env are responsible for its unusual neutralization sensitivity. Key determinants for this phenotype were mapped by generating chimeric Envs between MW965.26 Env and a typical resistant Env clone, the consensus C (ConC) clone, and localized to two residues, Cys384 in the C3 domain and Asn502 in the C5 domain. Substituting the sensitizing mutations Y384C and K502N at these positions into several resistant primary Envs resulted in conversion to neutralization-sensitive phenotypes, demonstrating the generalizability of this effect. In contrast to the sensitizing effects of these substitutions on normally masked epitopes, these mutations reduced the sensitivity of VRC01-like epitopes overlapping the CD4-binding domain, while they had no effect on several other classes of broadly neutralizing epitopes, including members of several lineages of V2-dependent quaternary epitopes and representatives of N332 glycan-dependent epitopes (PGT121) and quaternary, cleavage-dependent epitopes centered at the gp41-gp120 interface on intact HIV-1 Env trimers (PGT151). These results identify novel substitutions in gp120 that regulate the expression of alternative conformations of Env and differentially affect the exposure of different classes of epitopes, thereby influencing the neutralization phenotype of primary HIV-1 isolates.IMPORTANCE A better understanding of the mechanisms that determine the wide range of neutralization sensitivity of circulating primary HIV-1 isolates would provide important information about the natural structural and conformational diversity of HIV-1 Env and how this affects the neutralization phenotype. A useful way of studying this is to determine the molecular basis for the unusually high neutralization sensitivities of the limited number of available tier 1a viruses. This study localized the neutralization sensitivity of MW965.26, an extremely sensitive subtype C-derived primary isolate, to two rare substitutions in the C3 and C5 domains and demonstrated that the sequences at these positions differentially affect the presentation of epitopes recognized by different classes of standard and conformation-dependent broadly neutralizing antibodies. These results provide novel insight into how these regions regulate the neutralization phenotype and provide tools for controlling the Env conformation that could have applications both for structural studies and in vaccine design.
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Mikulak J, Di Vito C, Zaghi E, Mavilio D. Host Immune Responses in HIV-1 Infection: The Emerging Pathogenic Role of Siglecs and Their Clinical Correlates. Front Immunol 2017; 8:314. [PMID: 28386256 PMCID: PMC5362603 DOI: 10.3389/fimmu.2017.00314] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 03/06/2017] [Indexed: 11/25/2022] Open
Abstract
A better understanding of the mechanisms employed by HIV-1 to escape immune responses still represents one of the major tasks required for the development of novel therapeutic approaches targeting a disease still lacking a definitive cure. Host innate immune responses against HIV-1 are key in the early phases of the infection as they could prevent the development and the establishment of two hallmarks of the infection: chronic inflammation and viral reservoirs. Sialic acid-binding immunoglobulin-like lectins (Siglecs) belong to a family of transmembrane proteins able to dampen host immune responses and set appropriate immune activation thresholds upon ligation with their natural ligands, the sialylated carbohydrates. This immune-modulatory function is also targeted by many pathogens that have evolved to express sialic acids on their surface in order to escape host immune responses. HIV-1 envelope glycoprotein 120 (gp120) is extensively covered by carbohydrates playing active roles in life cycle of the virus. Indeed, besides forming a protecting shield from antibody recognition, this coat of N-linked glycans interferes with the folding of viral glycoproteins and enhances virus infectivity. In particular, the sialic acid residues present on gp120 can bind Siglec-7 on natural killer and monocytes/macrophages and Siglec-1 on monocytes/macrophages and dendritic cells. The interactions between these two members of the Siglec family and the sialylated glycans present on HIV-1 envelope either induce or increase HIV-1 entry in conventional and unconventional target cells, thus contributing to viral dissemination and disease progression. In this review, we address the impact of Siglecs in the pathogenesis of HIV-1 infection and discuss how they could be employed as clinic and therapeutic targets.
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Affiliation(s)
- Joanna Mikulak
- Unit of Clinical and Experimental Immunology, Humanitas Clinical and Research Center, Rozzano, Italy; Istituto di Ricerca Genetica e Biomedica, UOS di Milano, Consiglio Nazionale delle Ricerche (UOS/IRGB/CNR), Rozzano, Italy
| | - Clara Di Vito
- Unit of Clinical and Experimental Immunology, Humanitas Clinical and Research Center , Rozzano , Italy
| | - Elisa Zaghi
- Unit of Clinical and Experimental Immunology, Humanitas Clinical and Research Center , Rozzano , Italy
| | - Domenico Mavilio
- Unit of Clinical and Experimental Immunology, Humanitas Clinical and Research Center, Rozzano, Italy; Department of Medical Biotechnologies and Translational Medicine (BioMeTra), University of Milan, Milan, Italy
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Colson P, Ravaux I, Tamalet C, Glazunova O, Baptiste E, Chabriere E, Wiedemann A, Lacabaratz C, Chefrour M, Picard C, Stein A, Levy Y, Raoult D. HIV infection en route to endogenization: two cases. Clin Microbiol Infect 2014; 20:1280-8. [PMID: 25366539 PMCID: PMC4360783 DOI: 10.1111/1469-0691.12807] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 10/28/2014] [Accepted: 10/28/2014] [Indexed: 12/30/2022]
Abstract
The long-term spontaneous evolution of humans and the human immunodeficiency virus (HIV) is not well characterized; many vertebrate species, including humans, exhibit remnants of other retroviruses in their genomes that question such possible endogenization of HIV. We investigated two HIV-infected patients with no HIV-related disease and no detection with routine tests of plasma HIV RNA or cell-associated HIV DNA. We used Sanger and deep sequencing to retrieve HIV DNA sequences integrated in the human genome and tested the host humoral and cellular immune responses. We noticed that viruses from both patients were inactivated by the high prevalence of the transformation of tryptophan codons into stop codons (25% overall (3-100% per gene) and 24% overall (0-50% per gene)). In contrast, the humoral and/or cellular responses were strong for one patient and moderate for the other, indicating that a productive infection occurred at one stage of the infection. We speculate that the stimulation of APOBEC, the enzyme group that exchanges G for A in viral nucleic acids and is usually inhibited by the HIV protein Vif, has been amplified and made effective from the initial stage of the infection. Furthermore, we propose that a cure for HIV may occur through HIV endogenization in humans, as observed for many other retroviruses in mammals, rather than clearance of all traces of HIV from human cells, which defines viral eradication.
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Affiliation(s)
- P Colson
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), UM63 CNRS 7278 IRD 198 INSERM U1095, Aix-Marseille Université, Marseille, France; Fondation Institut Hospitalo-Universitaire (IHU) MéiterranéInfection, Pôle des Maladies Infectieuses et Tropicales Clinique et Biologique, Fédération de Bactériologie-Hygiène-Virologie, Centre Hospitalo-Universitaire Timone, Assistance Publique-Hôpitaux de Marseille, Marseille, France
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Abstract
UNLABELLED The HIV-1 envelope protein (Env) is heavily glycosylated, with approximately 50% of the Env molecular mass being contributed by N-glycans. HIV-1 Env N-glycans shield the protein backbone and have been shown to play key roles in determining Env structure, surface exposure, and, consequently, antigenicity, infectivity, antibody neutralization, and carbohydrate and receptor binding. Studies of HIV-1 glycosylation have focused mainly on the position of glycosylation, rather than the types of glycans. Also, the role of Env glycan moieties on HIV-1 transmission has not been systematically defined. Using viruses with modified Env glycan content and heterogeneity, we examined the effects of Env glycan moieties on the major events of HIV-1 transmission. Compared to viruses with less oligomannose and more complex Env glycans, viruses with more oligomannose and less complex glycans more efficiently (i) transcytosed across an epithelial cell monolayer, (ii) attached to monocyte-derived macrophages (MDMs), (iii) bound monocyte-derived dendritic cells (MoDCs), and (iv) trans-infected primary lymphocytes via MoDCs. However, viruses with more oligomannose and less complex glycans displayed impaired infectivity in TZMbl cells, MDMs, primary lymphocytes, and fresh human intestinal tissue. Thus, N-linked Env glycans display discordant effects on the major events of HIV-1 transmission, with mature oligosaccharide structures on Env playing a crucial role in HIV-1 infection. Env glycosylation should be taken into consideration in the development of vaccine strategies to interdict HIV-1 transmission. IMPORTANCE HIV-1 Env N-glycans shield the protein backbone and play key roles in determining Env structure and surface exposure, thereby impacting Env antigenicity, infectivity, antibody neutralization, and carbohydrate and receptor binding. Studies of HIV-1 glycosylation have focused mainly on the position of glycosylation, rather than the types of glycans. In the study described in this report, we investigated systematically the role of Env glycan moieties on HIV-1 transmission. We show that N-linked Env glycans display discordant effects on the major events of HIV-1 transmission. These data indicate that Env glycan moieties impact HIV-1 transmission and that modulation of Env glycan moieties offers a potential strategy for the development of therapeutic or prophylactic vaccines against HIV-1.
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Raska M, Czernekova L, Moldoveanu Z, Zachova K, Elliott MC, Novak Z, Hall S, Hoelscher M, Maboko L, Brown R, Smith PD, Mestecky J, Novak J. Differential glycosylation of envelope gp120 is associated with differential recognition of HIV-1 by virus-specific antibodies and cell infection. AIDS Res Ther 2014; 11:23. [PMID: 25120578 PMCID: PMC4130436 DOI: 10.1186/1742-6405-11-23] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 07/26/2014] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND HIV-1 entry into host cells is mediated by interactions between the virus envelope glycoprotein (gp120/gp41) and host-cell receptors. N-glycans represent approximately 50% of the molecular mass of gp120 and serve as potential antigenic determinants and/or as a shield against immune recognition. We previously reported that N-glycosylation of recombinant gp120 varied, depending on the producer cells, and the glycosylation variability affected gp120 recognition by serum antibodies from persons infected with HIV-1 subtype B. However, the impact of gp120 differential glycosylation on recognition by broadly neutralizing monoclonal antibodies or by polyclonal antibodies of individuals infected with other HIV-1 subtypes is unknown. METHODS Recombinant multimerizing gp120 antigens were expressed in different cells, HEK 293T, T-cell, rhabdomyosarcoma, hepatocellular carcinoma, and Chinese hamster ovary cell lines. Binding of broadly neutralizing monoclonal antibodies and polyclonal antibodies from sera of subtype A/C HIV-1-infected subjects with individual gp120 glycoforms was assessed by ELISA. In addition, immunodetection was performed using Western and dot blot assays. Recombinant gp120 glycoforms were tested for inhibition of infection of reporter cells by SF162 and YU.2 Env-pseudotyped R5 viruses. RESULTS We demonstrated, using ELISA, that gp120 glycans sterically adjacent to the V3 loop only moderately contribute to differential recognition of a short apex motif GPGRA and GPGR by monoclonal antibodies F425 B4e8 and 447-52D, respectively. The binding of antibodies recognizing longer peptide motifs overlapping with GPGR epitope (268 D4, 257 D4, 19b) was significantly altered. Recognition of gp120 glycoforms by monoclonal antibodies specific for other than V3-loop epitopes was significantly affected by cell types used for gp120 expression. These epitopes included CD4-binding site (VRC03, VRC01, b12), discontinuous epitope involving V1/V2 loop with the associated glycans (PG9, PG16), and an epitope including V3-base-, N332 oligomannose-, and surrounding glycans-containing epitope (PGT 121). Moreover, the different gp120 glycoforms variably inhibited HIV-1 infection of reporter cells. CONCLUSION Our data support the hypothesis that the glycosylation machinery of different cells shapes gp120 glycosylation and, consequently, impacts envelope recognition by specific antibodies as well as the interaction of HIV-1 gp120 with cellular receptors. These findings underscore the importance of selection of appropriately glycosylated HIV-1 envelope as a vaccine antigen.
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Andrianov AM, Kornoushenko YV, Kashyn IA, Kisel MA, Tuzikov AV. In silico design of novel broad anti-HIV-1 agents based on glycosphingolipid β-galactosylceramide, a high-affinity receptor for the envelope gp120 V3 loop. J Biomol Struct Dyn 2014; 33:1051-66. [PMID: 24942968 DOI: 10.1080/07391102.2014.926832] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Novel anti-Human immunodeficiency virus (HIV)-1 agents targeting the V3 loop of envelope protein gp120 were designed by computer modeling based on glycosphingolipid β-galactosylceramide (β-GalCer), which is an alternative receptor allowing HIV-1 entry into CD4-negative cells of neural and colonic origin. Models of these β-GalCer analogs bound to the V3 loops from five various HIV-1 variants were generated by molecular docking and their stability was estimated by molecular dynamics (MDs) and binding free energy simulations. Specific binding to the V3 loop was accomplished primarily by non-conventional XH…π interactions between CH/OH sugar groups of the glycolipids and the conserved V3 residues with π-conjugated side chains. The designed compounds were found to block the tip and/or the base of the V3 loop, which form invariant structural motifs that contain residues critical for cell tropism. With the MDs calculations, the docked models of the complexes of the β-GalCer analogs with V3 are energetically stable in all of the cases of interest and exhibit low values of free energy of their formation. Based on the data obtained, these compounds are considered as promising basic structures for the rational design of novel, potent, and broad-spectrum anti-HIV-1 therapeutics.
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Affiliation(s)
- Alexander M Andrianov
- a Institute of Bioorganic Chemistry , National Academy of Sciences of Belarus , Kuprevich Street 5/2, Minsk 220141 , Republic of Belarus
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A virus-envelope paired competitive assay to study entry efficiency of human immunodeficiency virus type 1 in vitro. J Virol Methods 2014; 205:91-8. [PMID: 24859049 DOI: 10.1016/j.jviromet.2014.05.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 05/09/2014] [Accepted: 05/13/2014] [Indexed: 10/25/2022]
Abstract
The efficiency of the human immunodeficiency virus type-1 (HIV-1) to enter cells is defined primarily by amino acid exchanges in the external glycoprotein gp120 and in, especially its highly variable V3 loop region. To study entry efficiency of HIV-1 a competitive viral entry assay was developed, to be comprised of infectious virus as well as soluble gp120 (sgp120) as an entry competitor. Entry of viruses using the coreceptor CXCR4 was reduced by adding CXCR4-tropic sgp120 (X4-sgp120) SF2 or LAV expressed in the baculovirus system or by adding X4-sgp120 from NL-952 and NL-V3A virus mutants produced in a HeLa-P4 cell culture expression system. Adding X4-sgp120 into a CCR5-specific infection assay revealed that X4-sgp120 enhanced the infection of CCR5-tropic virus. Furthermore, the role of the V3 loop N-glycan g15 on entry efficiency was studied using virus mutants and sgp120 with different N-glycosylation and different coreceptor usage. These experiments showed that viral entry of R5-tropic viruses lacking the N-glycan g15 within the V3 loop was inhibited by CCR5-tropic sgp120 harboring the g15 N-glycan. Altogether, the data demonstrate that HIV-1 entry efficiency can be studied easily by using sgp120 as an internal control or by using autologous or heterologous sgp120-virus pairs.
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13
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Loss of a conserved N-linked glycosylation site in the simian immunodeficiency virus envelope glycoprotein V2 region enhances macrophage tropism by increasing CD4-independent cell-to-cell transmission. J Virol 2014; 88:5014-28. [PMID: 24554659 DOI: 10.1128/jvi.02785-13] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
UNLABELLED Human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) strains differ in their capacity to replicate in macrophages, but mechanisms underlying these differences are not fully understood. Here, we identify a highly conserved N-linked glycosylation site (N173 in SIV, corresponding to N160 in HIV) in the V2 region of the SIV envelope glycoprotein (Env) as a novel determinant of macrophage tropism and characterize mechanisms underlying this phenotype. Loss of the N173 glycosylation site in the non-macrophage-tropic SIVmac239 by introducing an N173Q mutation enhanced viral replication and multinucleated giant cell formation upon infection of rhesus macrophages, while the addition of N173 to SIVmac251 had the opposite effect. The removal of N173 in SIVmac239 enhanced CD4-independent cell-to-cell transmission to CCR5-expressing cells. SIVmac239 with N173Q mediated CD4-independent cell-cell fusion but could not infect CD4-negative cells in single-round infections. Thus, CD4-independent phenotypes were detected only in the context of cell-to-cell contact. Similar results were obtained in SIVmac251 with and without N173. N173 decreased the neutralization sensitivity of SIVmac251 but had no effect on the neutralization sensitivity of SIVmac239. The N173Q mutation had no effect on SIVmac239 binding to CD4 in Biacore assays, coimmunoprecipitation assays, and enzyme-linked immunosorbent assays (ELISAs). These findings suggest that the loss of the N173 N-linked glycosylation site increases SIVmac239 replication in macrophages by enhancing CD4-independent cell-to-cell virus transmission through CCR5-mediated fusion. This mechanism may facilitate the escape of macrophage-tropic viruses from neutralizing antibodies while promoting spreading infection by these viruses in vivo. IMPORTANCE In this study, we identify a genetic determinant in the viral envelope (N173) that increases replication and spreading infection of SIV strains in macrophages by enhancing cell-to-cell virus transmission. This effect is explained by a novel mechanism involving increased cell-to-cell fusion in the absence of CD4, the primary receptor that normally mediates virus entry. The same genetic determinant also affects the sensitivity of these viruses to inhibition by neutralizing antibodies. Most macrophage-tropic HIV/SIV strains are known to be neutralization sensitive. Together, these findings suggest that this efficient mode of virus transmission may facilitate the escape of macrophage-tropic viruses from neutralizing antibodies while promoting spreading infection by these viruses to cells expressing little or no CD4 in vivo.
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Andrianov AM, Kashyn IA, Tuzikov AV. Discovery of novel anti-HIV-1 agents based on a broadly neutralizing antibody against the envelope gp120 V3 loop: a computational study. J Biomol Struct Dyn 2013; 32:1993-2004. [DOI: 10.1080/07391102.2013.848825] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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15
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Mathematical models: a key to understanding HIV envelope interactions? J Immunol Methods 2013; 398-399:1-18. [PMID: 24041473 DOI: 10.1016/j.jim.2013.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 07/17/2013] [Accepted: 09/02/2013] [Indexed: 11/23/2022]
Abstract
The spikes of the human immunodeficiency virus (HIV) mediate viral entry and are the most important targets for neutralizing antibodies. Each spike consists of three identical subunits. The role of the spike's subunits in antibody binding is not fully understood. One experimental approach to analyze trimer function uses assays with mixed envelope trimer expressing cells or viruses. As these experiments do not allow direct observation of subunit functions, mathematical models are required to interpret them. Here we describe a modeling framework to study (i) the interaction of the V1V2 loop with epitopes on the V3 loop and (ii) the composition of quaternary epitopes. In a first step we identify which trimers can form in these assays and how they function under antibody binding. We then derive the behavior of an average trimer. We contrast two experimental reporting systems and list their advantages and disadvantages. In these experiments trimer formation might not be perfectly random and we show how these effects can be tested. As we still lack a potent vaccine against HIV, and this vaccine surely has to stimulate the production of neutralizing antibodies, mixed trimer approaches in combination with mathematical models will help to identify vulnerable sites of the HIV spike.
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Andrianov AM, Kornoushenko YV, Anishchenko IV, Eremin VF, Tuzikov AV. Structural analysis of the envelope gp120 V3 loop for some HIV-1 variants circulating in the countries of Eastern Europe. J Biomol Struct Dyn 2013; 31:665-83. [DOI: 10.1080/07391102.2012.706455] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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17
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Wilhelm D, Behnken HN, Meyer B. Glycosylation Assists Binding of HIV Protein gp120 to Human CD4 Receptor. Chembiochem 2012; 13:524-7. [DOI: 10.1002/cbic.201100740] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Indexed: 11/10/2022]
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Kumar R, Visciano ML, Li H, Hioe C. Targeting a Neutralizing Epitope of HIV Envelope Gp120 by Immune Complex Vaccine. ACTA ACUST UNITED AC 2012; S8. [PMID: 22891160 DOI: 10.4172/2155-6113.s8-002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
There are formidable challenges in developing HIV vaccines that elicit potent neutralizing antibodies against a broad array of HIV-1 isolates. The key targets for these neutralizing antibodies are the viral envelope antigens gp120 and gp41. Although broadly reactive neutralizing epitopes on gp120 and gp41 have been mapped and studied extensively, these epitopes are poorly immunogenic. Indeed, various vaccine candidates tested in preclinical and clinical trials do not generate antibodies against these epitopes. Hence, novel immunogen designs to augment the immunogenicity of these neutralizing epitopes are wanted. In this review, a unique immunogen design strategy that exploits immune complexes of gp120 and selected anti-gp120 monoclonal antibodies (mAb) to elicit neutralizing antibodies against cross-reactive V3 epitopes is discussed. The ability of these complexes to stimulate neutralizing antibodies is dictated by fine specificity and affinity of mAbs used to form the complexes, indicating the contribution of Fab-mediated activity, rather than conventional Fc-mediated enhancement. Further improvement of V3 immunogenicity is attainable by forming immune complexes with gp120 mutants lacking site-specific N-linked glycans. The increased V3 immunogenicity on the mutated gp120/mAb complexes correlates with enhancement of in vitro antibody recognition (antigenicity) and proteolytic resistance of V3 epitopes when presented on the complexes. These insights should provide guidelines for the development of more potent immunogens that target not only the prototypic V3 epitopes but also other broadly reactive epitopes on the HIV envelope.
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Affiliation(s)
- Rajnish Kumar
- New York University School of Medicine, Department of Pathology, New York, NY 10016, USA
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Bialuk I, Whitney S, Andresen V, Florese RH, Nacsa J, Cecchinato V, Valeri VW, Heraud JM, Gordon S, Parks RW, Montefiori DC, Venzon D, Demberg T, Guroff MR, Landucci G, Forthal DN, Franchini G. Vaccine induced antibodies to the first variable loop of human immunodeficiency virus type 1 gp120, mediate antibody-dependent virus inhibition in macaques. Vaccine 2011; 30:78-94. [PMID: 22037204 DOI: 10.1016/j.vaccine.2011.10.040] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 10/11/2011] [Accepted: 10/17/2011] [Indexed: 12/21/2022]
Abstract
The role of antibodies directed against the hyper variable envelope region V1 of human immunodeficiency virus type 1 (HIV-1), has not been thoroughly studied. We show that a vaccine able to elicit strain-specific non-neutralizing antibodies to this region of gp120 is associated with control of highly pathogenic chimeric SHIV(89.6P) replication in rhesus macaques. The vaccinated animal that had the highest titers of antibodies to the amino terminus portion of V1, prior to challenge, had secondary antibody responses that mediated cell killing by antibody-dependent cellular cytotoxicity (ADCC), as early as 2 weeks after infection and inhibited viral replication by antibody-dependent cell-mediated virus inhibition (ADCVI), by 4 weeks after infection. There was a significant inverse correlation between virus level and binding antibody titers to the envelope protein, (R=-0.83, p=0.015), and ADCVI (R=-0.84 p=0.044). Genotyping of plasma virus demonstrated in vivo selection of three SHIV(89.6P) variants with changes in potential N-linked glycosylation sites in V1. We found a significant inverse correlation between virus levels and titers of antibodies that mediated ADCVI against all the identified V1 virus variants. A significant inverse correlation was also found between neutralizing antibody titers to SHIV(89.6) and virus levels (R=-0.72 p=0.0050). However, passive inoculation of purified immunoglobulin from animal M316, the macaque that best controlled virus, to a naïve macaque, resulted in a low serum neutralizing antibodies and low ADCVI activity that failed to protect from SHIV(89.6P) challenge. Collectively, while our data suggest that anti-envelope antibodies with neutralizing and non-neutralizing Fc(R-dependent activities may be important in the control of SHIV replication, they also demonstrate that low levels of these antibodies alone are not sufficient to protect from infection.
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Affiliation(s)
- Izabela Bialuk
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, MD 20892, USA
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Zou Z, Chastain A, Moir S, Ford J, Trandem K, Martinelli E, Cicala C, Crocker P, Arthos J, Sun PD. Siglecs facilitate HIV-1 infection of macrophages through adhesion with viral sialic acids. PLoS One 2011; 6:e24559. [PMID: 21931755 PMCID: PMC3169630 DOI: 10.1371/journal.pone.0024559] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 08/14/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Human immunodeficiency virus type 1 (HIV-1) infects macrophages effectively, despite relatively low levels of cell surface-expressed CD4. Although HIV-1 infections are defined by viral tropisms according to chemokine receptor usage (R5 and X4), variations in infection are common within both R5- and X4-tropic viruses, indicating additional factors may contribute to viral tropism. METHODOLOGY AND PRINCIPAL FINDINGS Using both solution and cell surface binding experiments, we showed that R5- and X4-tropic HIV-1 gp120 proteins recognized a family of I-type lectin receptors, the Sialic acid-binding immunoglobulin-like lectins (Siglec). The recognition was through envelope-associated sialic acids that promoted viral adhesion to macrophages. The sialic acid-mediated viral-host interaction facilitated both R5-tropic pseudovirus and HIV-1(BaL) infection of macrophages. The high affinity Siglec-1 contributed the most to HIV-1 infection and the variation in Siglec-1 expression on primary macrophages from different donors was associated statistically with sialic acid-facilitated viral infection. Furthermore, envelope-associated sialoglycan variations on various strains of R5-tropic viruses also affected infection. CONCLUSIONS AND SIGNIFICANCE OF THE FINDINGS Our study showed that sialic acids on the viral envelope facilitated HIV-1 infection of macrophages through interacting with Siglec receptors, and the expression of Siglec-1 correlated with viral sialic acid-mediated host attachment. This glycan-mediated viral adhesion underscores the importance of viral sialic acids in HIV infection and pathogenesis, and suggests a novel class of antiviral compounds targeting Siglec receptors.
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Affiliation(s)
- Zhongcheng Zou
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Ashley Chastain
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Susan Moir
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jennifer Ford
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Kathryn Trandem
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Elena Martinelli
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Claudia Cicala
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Paul Crocker
- Cell Biology and Immunology, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - James Arthos
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Peter D. Sun
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
- * E-mail:
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Characterization of structural features and diversity of variable-region determinants of related quaternary epitopes recognized by human and rhesus macaque monoclonal antibodies possessing unusually potent neutralizing activities. J Virol 2011; 85:10730-40. [PMID: 21835798 DOI: 10.1128/jvi.00365-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
A series of potently neutralizing monoclonal antibodies (MAbs) that target quaternary epitopes on the native Env trimer have recently been described. A common feature shared by these antibodies is the critical involvement of sites in both the V2 and V3 variable domains in antibody recognition. In this study the gp120 variable-region determinants were mapped for eight rhesus macaque monoclonal antibodies (RhMAbs) possessing potently neutralizing activity specific for a quaternary target in SF162 Env and compared to those originally identified for human MAb 2909. These studies showed that determinants for the epitopes defined by the RhMAbs differed in both the V2 (positions 160, 167, and 169) and V3 (positions 313 and 315) regions from 2909, and in a number of cases, from each other. Attempts to reconstitute expression of these epitopes on the cell surface by cotransfecting Envs containing either the V2 or the V3 determinant of the epitope were not successful, suggesting that these epitopes were expressed on individual protomers in a trimer-dependent manner. Several of the V2 positions found to be critical for expression of these quaternary epitopes also significantly affected exposure and neutralization sensitivity of targets in the V3 and CD4-binding domains. These results demonstrated a considerable diversity in the fine structure of this class of epitopes and further suggested a potentially important relationship between the expression of such quaternary epitopes and V1/V2-mediated masking of immunodominant epitopes.
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Andrianov AM. Human immunodeficiency virus-1 gp120 V3 loop for anti-acquired immune deficiency syndrome drug discovery: computer-aided approaches to the problem solving. Expert Opin Drug Discov 2011; 6:419-35. [DOI: 10.1517/17460441.2011.560603] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Alexander M Andrianov
- Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, Kuprevich Street 5/2, 220141 Minsk, Republic of Belarus +375 17 2678263 ; +375 17 2241214 ;
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Lynch RM, Rong R, Boliar S, Sethi A, Li B, Mulenga J, Allen S, Robinson JE, Gnanakaran S, Derdeyn CA. The B cell response is redundant and highly focused on V1V2 during early subtype C infection in a Zambian seroconverter. J Virol 2011; 85:905-15. [PMID: 20980495 PMCID: PMC3020014 DOI: 10.1128/jvi.02006-10] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 10/21/2010] [Indexed: 12/13/2022] Open
Abstract
High-titer autologous neutralizing antibody responses have been demonstrated during early subtype C human immunodeficiency virus type 1 (HIV-1) infection. However, characterization of this response against autologous virus at the monoclonal antibody (MAb) level has only recently begun to be elucidated. Here we describe five monoclonal antibodies derived from a subtype C-infected seroconverter and their neutralizing activities against pseudoviruses that carry envelope glycoproteins from 48 days (0 month), 2 months, and 8 months after the estimated time of infection. Sequence analysis indicated that the MAbs arose from three distinct B cell clones, and their pattern of neutralization compared to that in patient plasma suggested that they circulated between 2 and 8 months after infection. Neutralization by MAbs representative of each B cell clone was mapped to two residues: position 134 in V1 and position 189 in V2. Mutational analysis revealed cooperative effects between glycans and residues at these two positions, arguing that they contribute to a single epitope. Analysis of the cognate gp120 sequence through homology modeling places this potential epitope near the interface between the V1 and V2 loops. Additionally, the escape mutation R189S in V2, which conferred resistance against all three MAbs, had no detrimental effect on virus replication in vitro. Taken together, our data demonstrate that independent B cells repeatedly targeted a single structure in V1V2 during early infection. Despite this assault, a single amino acid change was sufficient to confer complete escape with minimal impact on replication fitness.
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Affiliation(s)
- Rebecca M Lynch
- Emory Vaccine Center, Emory University, 954 Gatewood Rd., Atlanta, GA 30329, USA
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Abstract
We have used cryoelectron tomography of vitreous-ice-embedded HIV-1 virions to compare the envelope (Env) spikes of a wild-type strain with those of a mutant strain in which the V1/V2 loop has been deleted. Deletion of V1/V2 results in a spike with far more structural heterogeneity than is observed in the wild type, likely reflecting greatly enhanced gp120 protomer flexibility. A major difference between the two forms is a pronounced loss of mass from the "peak" of the native Env spike. The apparent loss of contact among three gp120 protomers likely accounts for the more open structure, heterogeneity in configuration, and previous observations that broadly neutralizing epitopes and reactive sites on other structural elements are more exposed in such constructs.
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Rao RSP, Wollenweber B. Subtle evolutionary changes in the distribution of N-glycosylation sequons in the HIV-1 envelope glycoprotein 120. Int J Biol Sci 2010; 6:407-18. [PMID: 20714439 PMCID: PMC2920574 DOI: 10.7150/ijbs.6.407] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 07/14/2010] [Indexed: 01/09/2023] Open
Abstract
Many viruses are known to undergo rapid evolutionary changes under selective pressures. The HIV-1 envelope glycoprotein 120 (gp120) shows extreme selection for NXS/T sequons, the potential sites of N-glycosylation. Although the average number of sequons in gp120 appears to be relatively stable in the recent past, even slight changes in the distribution of sequons may potentially play crucial roles in protein interaction and viral infection. This study tracked the prevalence and distribution of NXS/T sequons in gp120 over a period of 29 years (from 1981 to 2009). The gp120 showed location specific distribution of sequons with higher density in the outer domain of the molecule. The NXT sequon density decreased in the outer domain (despite the increase in the sequon specific amino acid threonine), but increased in the inner domain. By contrast, the NXS sequon density increased specifically in the outer domain. Related changes were also seen in the distribution probabilities of sequons in two domains. The results indicate that the gp120, chiefly in subtype B, is redistributing NXS/T sequons within the molecule with specific selection for NXS sequons. The subtle evolution of sequons in gp120 may have implications in viral resistance and infection.
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Affiliation(s)
- R Shyama Prasad Rao
- Aarhus University, Department of Genetics and Biotechnology, Slagelse 4200, Denmark.
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Envelope glycans of immunodeficiency virions are almost entirely oligomannose antigens. Proc Natl Acad Sci U S A 2010; 107:13800-5. [PMID: 20643940 DOI: 10.1073/pnas.1006498107] [Citation(s) in RCA: 279] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The envelope spike of HIV is one of the most highly N-glycosylated structures found in nature. However, despite extensive research revealing essential functional roles in infection and immune evasion, the chemical structures of the glycans on the native viral envelope glycoprotein gp120--as opposed to recombinantly generated gp120--have not been described. Here, we report on the identity of the N-linked glycans from primary isolates of HIV-1 (clades A, B, and C) and from the simian immunodeficiency virus. MS analysis reveals a remarkably simple and highly conserved virus-specific glycan profile almost entirely devoid of medial Golgi-mediated processing. In stark contrast to recombinant gp120, which shows extensive exposure to cellular glycosylation enzymes (>70% complex type glycans), the native envelope shows barely detectable processing beyond the biosynthetic intermediate Man5GlcNAc2 (<2% complex type glycans). This oligomannose (Man5-9GlcNAc2) profile is conserved across primary isolates and geographically divergent clades but is not reflected in the current generation of gp120 antigens used for vaccine trials. In the context of vaccine design, we also note that Manalpha1-->2Man-terminating glycans (Man6-9GlcNAc2) of the type recognized by the broadly neutralizing anti-HIV antibody 2G12 are 3-fold more abundant on the native envelope than on the recombinant monomer and are also found on isolates not neutralized by 2G12. The Manalpha1-->2Man residues of gp120 therefore provide a vaccine target that is physically larger and antigenically more conserved than the 2G12 epitope itself. This study revises and extends our understanding of the glycan shield of HIV with implications for AIDS vaccine design.
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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: 114] [Impact Index Per Article: 8.1] [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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François KO, Balzarini J. Potential of carbohydrate-binding agents as therapeutics against enveloped viruses. Med Res Rev 2010; 32:349-87. [PMID: 20577974 PMCID: PMC7168447 DOI: 10.1002/med.20216] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Twenty‐seven years after the discovery of HIV as the cause of AIDS more than 25 drugs directed against four different viral targets (i.e. reverse transcriptase, protease, integrase, envelope gp41) and one cellular target (i.e. CCR5 co‐receptor) are available for treatment. However, the search for an efficient vaccine is still ongoing. One of the main problems is the presence of a continuously evolving dense carbohydrate shield, consisting of N‐linked glycans that surrounds the virion and protects it against efficient recognition and persistent neutralization by the immune system. However, several lectins from the innate immune system specifically bind to these glycans in an attempt to process the virus antigens to provoke an immune response. Across a wide variety of different species in nature lectins can be found that can interact with the glycosylated envelope of HIV‐1 and can block the infection of susceptible cells by the virus. In this review, we will give an overview of the lectins from non‐mammalian origin that are endowed with antiviral properties and discuss the complex interactions between lectins of the innate immune system and HIV‐1. Also, attention will be given to different carbohydrate‐related modalities that can be exploited for antiviral chemotherapy. © 2010 Wiley Periodicals, Inc. Med Res Rev
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Affiliation(s)
- K O François
- Rega Institute for Medical Research, K. U. Leuven, B-3000 Leuven, Belgium
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Raska M, Novak J. Involvement of Envelope-Glycoprotein Glycans in HIV-1 Biology and Infection. Arch Immunol Ther Exp (Warsz) 2010; 58:191-208. [DOI: 10.1007/s00005-010-0072-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 11/30/2009] [Indexed: 01/24/2023]
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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 DOI: 10.1021/pr9002728] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [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, USA
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Li H, Xu CF, Blais S, Wan Q, Zhang HT, Landry SJ, Hioe CE. Proximal glycans outside of the epitopes regulate the presentation of HIV-1 envelope gp120 helper epitopes. THE JOURNAL OF IMMUNOLOGY 2009; 182:6369-78. [PMID: 19414790 DOI: 10.4049/jimmunol.0804287] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Glycosylation of HIV-1 envelope gp120 determines not only the proper structure, but also the immune responses against this Ag. Although glycans may be part of specific epitopes or shield other epitopes from T cells and Abs, this study provides evidence for a different immunomodulatory function of glycans associated with gp120 residues N230 and N448. These glycans are required for efficient MHC class II-restricted presentation of nearby CD4 T cell epitopes, even though they are not part of the epitopes. The glycans do not affect CD4 T cell recognition of more distant epitopes and are not essential for the proper folding and function of gp120. Data on CD4 T cell recognition of N448 mutants combined with proteolysis analyses and surface electrostatic potential calculation around residue N448 support the notion that N448 glycan near the epitope's C terminus renders the site to be surface accessible and allows its efficient processing. In contrast, the N230 glycan contributes to the nearby epitope presentation at a step other than the proteolytic processing of the epitope. Hence, N-glycans can determine CD4 T cell recognition of nearby gp120 epitopes by regulating the different steps in the MHC class II processing and presentation pathway after APCs acquire the intact gp120 Ag exogenously. Modifications of amino acids bearing glycans at the C termini of gp120 helper epitopes may prove to be a useful strategy for enhancing the immunogenicity of HIV-1 envelope gp120.
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Affiliation(s)
- Hualin Li
- Department of Veterans Affairs, New York Harbor Healthcare System, New York, NY, USA
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Granados-González V, Piedrahita LD, Martínez M, Genin C, Riffard S, Urcuqui-Inchima S. [Role of the HIV-1 gp120 V1/V2 domains in the induction of neutralizing antibodies]. Enferm Infecc Microbiol Clin 2009; 27:523-30. [PMID: 19409660 DOI: 10.1016/j.eimc.2008.02.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Accepted: 02/11/2008] [Indexed: 11/25/2022]
Abstract
The development of a preventive vaccine against human immunodeficiency virus type-1 (HIV-1) provides hope for control of the pandemic over the coming years. Nevertheless, it is clear that one of the greatest difficulties in achieving this vaccine is the high mutation rate of the virus, which enables it to evade the host's immune response. The production of neutralizing antibodies (NAb) against the HIV-1 envelope proteins is believed to play an important role in controlling the infection and in providing effective protection following vaccination. Several studies have shown that the V1/V2 domain of the HIV-1 gp120 envelope protein is involved in viral tropism during infection, in masking conserved neutralizing epitopes, in the conformational changes occurring after coreceptor binding, and in NAb induction. Nonetheless, this domain has been poorly investigated. However, because the V1/V2 domain is highly glycosylated, numerous studies have determined the influence of carbohydrates on NAb production. The present review focuses on the importance of NAb directed against epitopes of the variable regions, mainly V1/V2, their importance in protecting against HIV-1 infection, and the role these regions play in evading the immune response. Lastly, we will discuss the importance of NAb in the search for an effective vaccine against HIV-1.
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Affiliation(s)
- Viviana Granados-González
- Groupe Immunité des Muqueuses et Agents Pathogènes, University of Saint Etienne, Saint Etienne, Francia.
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Samleerat T, Thenin S, Jourdain G, Ngo-Giang-Huong N, Moreau A, Leechanachai P, Ithisuknanth J, Pagdi K, Wannarit P, Sangsawang S, Lallemant M, Barin F, Braibant M. Maternal neutralizing antibodies against a CRF01_AE primary isolate are associated with a low rate of intrapartum HIV-1 transmission. Virology 2009; 387:388-94. [PMID: 19303619 DOI: 10.1016/j.virol.2009.02.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Revised: 02/09/2009] [Accepted: 02/18/2009] [Indexed: 02/01/2023]
Abstract
Mother-to-child transmission (MTCT) of HIV-1 provides a model for studying the role of passively acquired antibodies in preventing HIV infection. We determined the titers of neutralizing antibodies (NAbs) against six primary isolates of clades B and CRF01_AE in sera from 45 transmitting and 45 nontransmitting mothers matched for the main independent factors associated with MTCT in Thailand. A lower risk of MTCT, particularly for intrapartum transmission, was associated only with higher NAb titers against the CRF01_AE strain, MBA. The envelope glycoprotein of this strain showed an unusually long V2 domain of 63 amino acids, encoding six potential N-linked glycosylation sites. We provided experimental data indicating that the extended V2 domain contributed to the higher level of resistance to neutralization by mothers' sera in this strain. Taken together the data suggest that some primary isolates with specific properties may be useful indicators for identifying protective antibodies.
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Polzer S, Müller H, Schreiber M. Effects of mutations on HIV-1 infectivity and neutralization involving the conserved NNNT amino acid sequence in the gp120 V3 loop. FEBS Lett 2009; 583:1201-6. [DOI: 10.1016/j.febslet.2009.03.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Revised: 02/25/2009] [Accepted: 03/09/2009] [Indexed: 01/04/2023]
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Auwerx J, François KO, Covens K, Van Laethem K, Balzarini J. Glycan deletions in the HIV-1 gp120 V1/V2 domain compromise viral infectivity, sensitize the mutant virus strains to carbohydrate-binding agents and represent a specific target for therapeutic intervention. Virology 2008; 382:10-9. [PMID: 18930512 DOI: 10.1016/j.virol.2008.09.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 07/24/2008] [Accepted: 09/08/2008] [Indexed: 01/17/2023]
Abstract
Carbohydrate-binding agents (CBAs), such as the mannose-specific Hippeastrum hybrid agglutinin (HHA) and the GlcNAc-specific Urtica dioica agglutinin (UDA), frequently select for glycan deletions in all different domains of HIV-1 gp120, except in the V1/V2 domain. To reveal the underlying mechanisms, a broad variety of 31 different virus strains containing one or several N-glycan deletions in V1/V2 of the gp120 of the X4-tropic HIV-1(NL4.3) were constructed by chimeric virus technology. No co-receptor switch to CCR5 was observed for any of the replication-competent mutant virus strains. With a few exceptions, the more glycans were deleted in the gp120 V1/V2 domain, the more the replication capacity of the mutant viruses became compromised. None of the mutant virus strains showed a markedly decreased sensitivity to the inhibitory activity of HHA and UDA. Instead, an up to 2- to 10-fold higher sensitivity to the inhibitory activity of these CBAs was observed. Our data may provide an explanation why glycan deletions in the gp120 V1/V2 domain rarely occur under CBA pressure and confirm the important functional role of the glycans in the HIV-1 gp120 V1/V2 domain. The gp120 V1/V2 loop glycans of HIV-1 should therefore be considered as a hot spot and novel target for specific therapeutic drug intervention.
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Affiliation(s)
- Joeri Auwerx
- Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, K.U.Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium
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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: 124] [Impact Index Per Article: 7.8] [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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Granados-Gonzalez V, Claret J, Berlier W, Vincent N, Urcuqui-Inchima S, Lucht F, Defontaine C, Pinter A, Genin C, Riffard S. Opposite immune reactivity of serum IgG and secretory IgA to conformational recombinant proteins mimicking V1/V2 domains of three different HIV type 1 subtypes depending on glycosylation. AIDS Res Hum Retroviruses 2008; 24:289-99. [PMID: 18260782 DOI: 10.1089/aid.2007.0187] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The V1/V2 domain of the HIV-1 gp120 envelope protein has been shown to contribute to viral cell tropism during infection and also to viral recognition by neutralizing monoclonal antibodies. However, this domain has been poorly investigated. Carbohydrates have been demonstrated to dramatically influence immune reactivity of antisera to viral glycoprotein antigens. In this study, DNA sequences coding for V1/V2 domains from HIV-1 primary isolates of three subtypes (A, B, and C) were subcloned into a secretion vector and used to transfect CHO cells that are able to achieve the glycosylation of proteins. The structure of purified recombinant V1/V2 proteins was tested using two anti-V1/V2 monoclonal antibodies directed against either a linear or a conformational and glycosylation-dependent epitope (8.22.2 and 697-D). Serum or saliva of 14/82 seropositive patients with anti-V1/V2 reactivity demonstrated good recognition of the recombinant proteins. Deglycosylation of the recombinant proteins was found to increase the reactivity of the serum IgG to the clade A and C but not to clade B V1/V2 domain demonstrating that the recognition of glycosylation sites by serum IgG is clade dependent. When considering SIgA from parotid saliva, deglycosylation of all recombinant proteins tested decreased the reactivity, suggesting that glycosylation plays an important role in the recognition of V1/V2 domain target epitopes by this class of antibodies. In conclusion, these results suggest the influence of carbohydrate moieties on the specificity of the antibodies to the V1/V2 domain produced during HIV infection and the potential importance of viral glycans in vaccine responses after mucosal administration.
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Affiliation(s)
- Viviana Granados-Gonzalez
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Julien Claret
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Willy Berlier
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Nadine Vincent
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | | | - Frederic Lucht
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Christiane Defontaine
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Abraham Pinter
- Laboratory of Retroviral Virology, Public Health Research Institute, Newark, New Jersey
| | - Christian Genin
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Serge Riffard
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
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Brass AL, Dykxhoorn DM, Benita Y, Yan N, Engelman A, Xavier RJ, Lieberman J, Elledge SJ. Identification of host proteins required for HIV infection through a functional genomic screen. Science 2008; 319:921-6. [PMID: 18187620 DOI: 10.1126/science.1152725] [Citation(s) in RCA: 1109] [Impact Index Per Article: 69.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
HIV-1 exploits multiple host proteins during infection. We performed a large-scale small interfering RNA screen to identify host factors required by HIV-1 and identified more than 250 HIV-dependency factors (HDFs). These proteins participate in a broad array of cellular functions and implicate new pathways in the viral life cycle. Further analysis revealed previously unknown roles for retrograde Golgi transport proteins (Rab6 and Vps53) in viral entry, a karyopherin (TNPO3) in viral integration, and the Mediator complex (Med28) in viral transcription. Transcriptional analysis revealed that HDF genes were enriched for high expression in immune cells, suggesting that viruses evolve in host cells that optimally perform the functions required for their life cycle. This effort illustrates the power with which RNA interference and forward genetics can be used to expose the dependencies of human pathogens such as HIV, and in so doing identify potential targets for therapy.
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Affiliation(s)
- Abraham L Brass
- Department of Genetics, Center for Genetics and Genomics, Brigham and Women's Hospital, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
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39
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Vigerust DJ. Pathobiology of virus glycosylation: implications to disease and prospects for treatment. Future Virol 2007. [DOI: 10.2217/17460794.2.6.615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Changes to the overall glycosylation profile of viral glycoproteins have been shown to be advantageous to virus survival and virulence. Many human viral pathogens rely on specific oligosaccharides to evade detection by the host immune system. Viruses such as HIV, Hendra, SARS-CoV, influenza, respiratory syncytial virus, hepatitis and West Nile virus rely on N-linked and O-Linked glycosylation for critical functions such as entry into host cells, proteolytic processing and protein trafficking. Recent findings demonstrate the importance of glycosylation to viral virulence, infectivity and immune evasion in several virus families impacting on human health. This review considers the role of glycosylation in viral infection and will detail several potential therapies for these important human pathogens and emerging infections.
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Affiliation(s)
- David J Vigerust
- Vanderbilt University Medical Center, Department of Pediatrics, Program in Vaccine Sciences, 1161 21st Avenue South, T-0107 MCN (Mailing), T-2219 MCN (Lab), Nashville, TN 37232-2007, USA
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40
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Meng Z, Xing H, He X, Ma L, Xu W, Shao Y. Genetic characterization of three newly isolated CRF07_BC near full-length genomes in China. AIDS Res Hum Retroviruses 2007; 23:1049-54. [PMID: 17725423 DOI: 10.1089/aid.2007.0058] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Though HIV-1 CRF07_BC rapidly spread in China, there have been few reports about this subtype since its first genetic characterization nearly 10 years ago. It was urgent and necessary to know the current gene variation of circulating CRF07_BC strains. Xinjiang was the main region for the CRF07_BC epidemic and also an ideal region for research on the viral gene evolution. The strains of Ulumuqi and Yili in Xinjiang were isolated, cloned, and sequenced in this study. Analyses of phylogenetic, potential CTL epitopes and N-glycosites were preformed simultaneously. New CRF07_BC isolates showed higher genetic diversity and more potential N-glycosites than old isolates. It was interesting that although the env and nef genes are highly variable, highly conserved potential CTL epitopes and N-glycosites were found in deduced gp120 V3 and Nef product of all CRF07_BC isolates. The analysis of the sequences provides some valuable information on the investigation of the epidemiology and on vaccine development.
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Affiliation(s)
- Zhefeng Meng
- Division of Virology and Immunology, State Key Laboratory for Infectious Disease Control and Prevention, National Center for AIDS/STD Control and Prevention, China CDC, Beijing 100050, PR China
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Vigerust DJ, Shepherd VL. Virus glycosylation: role in virulence and immune interactions. Trends Microbiol 2007; 15:211-8. [PMID: 17398101 PMCID: PMC7127133 DOI: 10.1016/j.tim.2007.03.003] [Citation(s) in RCA: 427] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Revised: 03/02/2007] [Accepted: 03/19/2007] [Indexed: 12/22/2022]
Abstract
The study of N-linked glycosylation as it relates to virus biology has become an area of intense interest in recent years due to its ability to impart various advantages to virus survival and virulence. HIV and influenza, two clear threats to human health, have been shown to rely on expression of specific oligosaccharides to evade detection by the host immune system. Additionally, other viruses such as Hendra, SARS-CoV, influenza, hepatitis and West Nile rely on N-linked glycosylation for crucial functions such as entry into host cells, proteolytic processing and protein trafficking. This review focuses on recent findings on the importance of glycosylation to viral virulence and immune evasion for several prominent human pathogens.
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Affiliation(s)
- David J Vigerust
- Department of Pediatrics, Program in Vaccine Sciences, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Roux KH, Taylor KA. AIDS virus envelope spike structure. Curr Opin Struct Biol 2007; 17:244-52. [PMID: 17395457 DOI: 10.1016/j.sbi.2007.03.008] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Revised: 02/26/2007] [Accepted: 03/16/2007] [Indexed: 11/30/2022]
Abstract
The envelope (Env) spikes on HIV-1 and closely related SIV define the viral tropism, mediate the fusion process and are the prime target of the humoral response. Despite intensive efforts, Env has been slow to reveal its structural and functional secrets. Three gp120 subunits comprise the 'head' of Env and three gp41 subunits comprise the 'stalk' and other membrane-associated elements. The recent description of the core structure of unliganded (untriggered) gp120, compared to earlier CD4-liganded atomic structures, reveals dramatic conformational reorganization of the components and suggests a mechanism for the initiation of fusion. The structure of the key V3 loop, both in isolation and in association with the liganded core, helps define its role in fusion and as a prime target of neutralizing antibodies. Additional details are emerging regarding the structure of gp41 as it transitions from the preliganded configuration to the fusion intermediate (fusion-active or prehairpin intermediate) configuration, although much remains speculative. Recent advances in cryoelectron tomography are giving us the first glimpses of the overall three-dimensional structure of Env, which, when fitted with the available component atomic structures, provides new insights into the organization of the structural elements within the trimeric spike.
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Affiliation(s)
- Kenneth H Roux
- Department of Biological Science and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4370, USA.
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