1
|
Xu HC, Pandey P, Ward H, Gorzkiewicz M, Abromavičiūtė D, Tinz C, Müller L, Meyer C, Pandyra AA, Yavas A, Borkhardt A, Esposito I, Lang KS, Lang PA. High-Affinity-Mediated Viral Entry Triggers Innate Affinity Escape Resulting in Type I IFN Resistance and Impaired T Cell Immunity. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 212:1457-1466. [PMID: 38497668 PMCID: PMC11016594 DOI: 10.4049/jimmunol.2300637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 02/23/2024] [Indexed: 03/19/2024]
Abstract
Increased receptor binding affinity may allow viruses to escape from Ab-mediated inhibition. However, how high-affinity receptor binding affects innate immune escape and T cell function is poorly understood. In this study, we used the lymphocytic choriomeningitis virus (LCMV) murine infection model system to create a mutated LCMV exhibiting higher affinity for the entry receptor α-dystroglycan (LCMV-GPH155Y). We show that high-affinity receptor binding results in increased viral entry, which is associated with type I IFN (IFN-I) resistance, whereas initial innate immune activation was not impaired during high-affinity virus infection in mice. Consequently, IFN-I resistance led to defective antiviral T cell immunity, reduced type II IFN, and prolonged viral replication in this murine model system. Taken together, we show that high-affinity receptor binding of viruses can trigger innate affinity escape including resistance to IFN-I resulting in prolonged viral replication.
Collapse
Affiliation(s)
- Haifeng C. Xu
- Department of Molecular Medicine II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Piyush Pandey
- Department of Molecular Medicine II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Harry Ward
- Department of Molecular Medicine II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Michal Gorzkiewicz
- Department of Molecular Medicine II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
- Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Džiuljeta Abromavičiūtė
- Department of Molecular Medicine II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Constanze Tinz
- Department of Molecular Medicine II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Lisa Müller
- Institute of Virology, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Caroline Meyer
- Institute of Virology, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Aleksandra A. Pandyra
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Center of Child and Adolescent Health, Heinrich Heine University, Düsseldorf, Germany
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research, Partner Site Bonn-Cologne, Bonn, Germany
| | - Aslihan Yavas
- Institute of Pathology, Medical Faculty, Heinrich Heine University and University Hospital of Düsseldorf, Düsseldorf, Germany
| | - Arndt Borkhardt
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Center of Child and Adolescent Health, Heinrich Heine University, Düsseldorf, Germany
| | - Irene Esposito
- Institute of Pathology, Medical Faculty, Heinrich Heine University and University Hospital of Düsseldorf, Düsseldorf, Germany
| | - Karl S. Lang
- Institute of Immunology, Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Philipp A. Lang
- Department of Molecular Medicine II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| |
Collapse
|
2
|
Gorzkiewicz M, Cramer J, Xu HC, Lang PA. The role of glycosylation patterns of viral glycoproteins and cell entry receptors in arenavirus infection. Biomed Pharmacother 2023; 166:115196. [PMID: 37586116 DOI: 10.1016/j.biopha.2023.115196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/14/2023] [Accepted: 07/18/2023] [Indexed: 08/18/2023] Open
Abstract
Mammarenaviruses are enveloped RNA viruses that can be associated with rodent-transmitted diseases in humans. Their virions are composed of a nucleocapsid surrounded by a lipid bilayer with glycoprotein (GP) spikes interacting with receptors on target cells. Both the GP and receptors are highly glycosylated, with glycosylation patterns being crucial for virus binding and cell entry, viral tropism, immune responses, or therapy strategies. These effects have been previously described for several different viruses. In case of arenaviruses, they remain insufficiently understood. Thus, it is important to determine the mechanisms of glycosylation of viral proteins and receptors responsible for infection, in order to fully understand the biology of arenaviruses. In this article, we have summarized and critically evaluated the available literature data on the glycosylation of mammarenavirus-associated proteins to facilitate further research in this field.
Collapse
Affiliation(s)
- Michal Gorzkiewicz
- Department of Molecular Medicine II, Medical Faculty, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany; Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, 141/143 Pomorska St., 90-236 Lodz, Poland.
| | - Jonathan Cramer
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Haifeng C Xu
- Department of Molecular Medicine II, Medical Faculty, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Philipp A Lang
- Department of Molecular Medicine II, Medical Faculty, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
| |
Collapse
|
3
|
Pseudotyped Viruses for Lyssavirus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1407:191-208. [PMID: 36920698 DOI: 10.1007/978-981-99-0113-5_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Lyssaviruses, which belong to the family Rhabdoviridae, are enveloped and bullet-shaped ssRNA viruses with genetic diversity. All members of Lyssavirus genus are known to infect warm-blooded animals and cause the fatal disease rabies. The rabies virus (RABV) in lyssavirus is the major pathogen to cause fatal rabies. The pseudotyped RABV is constructed to study the biological functions of G protein and evaluation of anti-RABV products including vaccine-induced antisera, rabies immunoglobulins (RIG), neutralizing mAbs, and other antiviral inhibitors. In this chapter, we focus on RABV as a representative and describe the construction of RABV G protein bearing pseudotyped virus and its applications. Other non-RABV lyssaviruses are also included.
Collapse
|
4
|
Stachura P, Stencel O, Lu Z, Borkhardt A, Pandyra AA. Arenaviruses: Old viruses present new solutions for cancer therapy. Front Immunol 2023; 14:1110522. [PMID: 37033933 PMCID: PMC10079900 DOI: 10.3389/fimmu.2023.1110522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 03/13/2023] [Indexed: 04/11/2023] Open
Abstract
Viral-based cancer therapies have tremendous potential, especially in the context of treating poorly infiltrated cold tumors. However, in tumors with intact anti-viral interferon (IFN) pathways, while some oncolytic viruses induce strong innate and adaptive immune responses, they are neutralized before exerting their therapeutic effect. Arenaviruses, particularly the lymphocytic choriomeningitis virus (LCMV) is a noncytopathic virus with preferential cancer tropism and evolutionary mechanisms to escape the immune system for longer and to block early clearance. These escape mechanisms include inhibition of the MAVS dependent IFN pathway and spike protein antigen masking. Regarding its potential for cancer treatment, LCMV is therefore able to elicit long-term responses within the tumor microenvironment (TME), boost anti-tumor immune responses and polarize poorly infiltrating tumors towards a hot phenotype. Other arenaviruses including the attenuated Junin virus vaccine also have anti-tumor effects. Furthermore, the LCMV and Pichinde arenaviruses are currently being used to create vector-based vaccines with attenuated but replicating virus. This review focuses on highlighting the potential of arenaviruses as anti-cancer therapies. This includes providing a molecular understanding of its tropism as well as highlighting past and present preclinical and clinical applications of noncytophatic arenavirus therapies and their potential in bridging the gap in the treatment of cancers weakly responsive or unresponsive to oncolytic viruses. In summary, arenaviruses represent promising new therapies to broaden the arsenal of anti-tumor therapies for generating an immunogenic tumor microenvironment.
Collapse
Affiliation(s)
- Paweł Stachura
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
- Department of Molecular Medicine II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Olivia Stencel
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Zhe Lu
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Arndt Borkhardt
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Aleksandra A. Pandyra
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
- *Correspondence: Aleksandra A. Pandyra,
| |
Collapse
|
5
|
Enriquez AS, Buck TK, Li H, Norris MJ, Moon-Walker A, Zandonatti MA, Harkins SS, Robinson JE, Branco LM, Garry RF, Saphire EO, Hastie KM. Delineating the mechanism of anti-Lassa virus GPC-A neutralizing antibodies. Cell Rep 2022; 39:110841. [PMID: 35613585 PMCID: PMC9258627 DOI: 10.1016/j.celrep.2022.110841] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 03/16/2022] [Accepted: 04/28/2022] [Indexed: 12/16/2022] Open
Abstract
Lassa virus (LASV) is the etiologic agent of Lassa Fever, a hemorrhagic disease that is endemic to West Africa. During LASV infection, LASV glycoprotein (GP) engages with multiple host receptors for cell entry. Neutralizing antibodies against GP are rare and principally target quaternary epitopes displayed only on the metastable, pre-fusion conformation of GP. Currently, the structural features of the neutralizing GPC-A antibody competition group are understudied. Structures of two GPC-A antibodies presented here demonstrate that they bind the side of the pre-fusion GP trimer, bridging the GP1 and GP2 subunits. Complementary biochemical analyses indicate that antibody 25.10C, which is broadly specific, neutralizes by inhibiting binding of the endosomal receptor LAMP1 and also by blocking membrane fusion. The other GPC-A antibody, 36.1F, which is lineage-specific, prevents LAMP1 association only. These data illuminate a site of vulnerability on LASV GP and will guide efforts to elicit broadly reactive therapeutics and vaccines. Enriquez et al. present two structures of GPC-A antibody Fab fragments bound to Lassa virus glycoprotein. Complementary biochemical analyses illuminate mechanistic differences between pan-Lassa 25.10C and lineage-specific 36.1F. 25.10C inhibits two steps of Lassa virus infection, LAMP1 binding and membrane fusion, while 36.1F only blocks LAMP1.
Collapse
Affiliation(s)
| | - Tierra K Buck
- La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | - Haoyang Li
- La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | | | - Alex Moon-Walker
- La Jolla Institute for Immunology, La Jolla, CA 92037, USA; Program in Virology, Harvard University, Boston, MA 02115, USA; Department of Molecular Microbiology, Washington University in Saint Louis, St. Louis, MO 63130, USA
| | | | | | - James E Robinson
- Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | | | - Robert F Garry
- Zalgen Labs, LLC, Germantown, MD 20876, USA; Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | | | | |
Collapse
|
6
|
Mantlo EK, Maruyama J, Manning JT, Wanninger TG, Huang C, Smith JN, Patterson M, Paessler S, Koma T. Machupo Virus with Mutations in the Transmembrane Domain and Glycosylation Sites of the Glycoprotein Is Attenuated and Immunogenic in Animal Models of Bolivian Hemorrhagic Fever. J Virol 2022; 96:e0020922. [PMID: 35343792 PMCID: PMC9044957 DOI: 10.1128/jvi.00209-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 02/15/2022] [Indexed: 12/28/2022] Open
Abstract
Several highly pathogenic mammarenaviruses cause severe hemorrhagic and neurologic disease in humans for which vaccines and antivirals are limited or unavailable. New World (NW) mammarenavirus Machupo virus (MACV) infection causes Bolivian hemorrhagic fever in humans. We previously reported that the disruption of specific N-linked glycan sites on the glycoprotein (GPC) partially attenuates MACV in an interferon alpha/beta and gamma (IFN-α/β and -γ) receptor knockout (R-/-) mouse model. However, some capability to induce neurological pathology still remained. The highly pathogenic Junin virus (JUNV) is another NW arenavirus closely related to MACV. An F427I substitution in the GPC transmembrane domain (TMD) rendered JUNV attenuated in a lethal mouse model after intracranial inoculation. In this study, we rationally designed and rescued a MACV containing mutations at two glycosylation sites and the corresponding F438I substitution in the GPC TMD. The MACV mutant is fully attenuated in IFN-α/β and -γ R-/- mice and outbred guinea pigs. Furthermore, inoculation with this mutant MACV completely protected guinea pigs from wild-type MACV lethal challenge. Last, we found the GPC TMD F438I substitution greatly impaired MACV growth in neuronal cell lines of mouse and human origins. Our results highlight the critical roles of the glycans and the TMD on the GPC in arenavirus virulence, which provide insight into the rational design of potential vaccine candidates for highly pathogenic arenaviruses. IMPORTANCE For arenaviruses, the only vaccine available is the live attenuated Candid#1 vaccine, a JUNV vaccine approved in Argentina. We and others have found that the glycans on GPC and the F427 residue in the GPC TMD are important for virulence of JUNV. Nevertheless, mutating either of them is not sufficient for full and stable attenuation of JUNV. Using reverse genetics, we disrupted specific glycosylation sites on MACV GPC and also introduced the corresponding F438I substitution in the GPC TMD. This MACV mutant is fully attenuated in two animal models and protects animals from lethal infection. Thus, our studies highlight the feasibility of rational attenuation of highly pathogenic arenaviruses for vaccine development. Another important finding from this study is that the F438I substitution in GPC TMD could substantially affect MACV replication in neurons. Future studies are warranted to elucidate the underlying mechanism and the implication of this mutation in arenavirus neural tropism.
Collapse
Affiliation(s)
- Emily K. Mantlo
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, USA
| | - Junki Maruyama
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, USA
| | - John T. Manning
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, USA
| | - Timothy G. Wanninger
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, USA
| | - Cheng Huang
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, USA
| | - Jeanon N. Smith
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, USA
| | - Michael Patterson
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, USA
| | - Slobodan Paessler
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, USA
| | - Takaaki Koma
- Department of Microbiology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| |
Collapse
|
7
|
Feng T, Zhang J, Chen Z, Pan W, Chen Z, Yan Y, Dai J. Glycosylation of viral proteins: Implication in virus-host interaction and virulence. Virulence 2022; 13:670-683. [PMID: 35436420 PMCID: PMC9037552 DOI: 10.1080/21505594.2022.2060464] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Glycans are among the most important cell molecular components. However, given their structural diversity, their functions have not been fully explored. Glycosylation is a vital post-translational modification for various proteins. Many bacteria and viruses rely on N-linked and O-linked glycosylation to perform critical biological functions. The diverse functions of glycosylation on viral proteins during viral infections, including Dengue, Zika, influenza, and human immunodeficiency viruses as well as coronaviruses have been reported. N-linked glycosylation is the most common form of protein modification, and it modulates folding, transportation and receptor binding. Compared to N-linked glycosylation, the functions of O-linked viral protein glycosylation have not been comprehensively evaluated. In this review, we summarize findings on viral protein glycosylation, with particular attention to studies on N-linked glycosylation in viral life cycles. This review informs the development of virus-specific vaccines or inhibitors.
Collapse
Affiliation(s)
- Tingting Feng
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Jinyu Zhang
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Zhiqian Chen
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Wen Pan
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Zhengrong Chen
- Department of Respiratory Medicine, Children's Hospital of Soochow University, Soochow University, Suzhou, China
| | - Yongdong Yan
- Department of Respiratory Medicine, Children's Hospital of Soochow University, Soochow University, Suzhou, China
| | - Jianfeng Dai
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Suzhou, China
| |
Collapse
|
8
|
Joseph AA, Fasipe OJ, Joseph OA, Olatunji OA. Contemporary and emerging pharmacotherapeutic agents for the treatment of Lassa viral haemorrhagic fever disease. J Antimicrob Chemother 2022; 77:1525-1531. [PMID: 35296886 DOI: 10.1093/jac/dkac064] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This review was designed to discuss the emerging and current pharmacotherapeutic agents for the treatment of Lassa viral haemorrhagic fever disease (LVHFD), also known as Lassa fever (LF). Original peer-reviewed articles that investigated LF were identified using the Medline Entrez-PubMed search. Information was also sourced from printed textbooks and reports by recognized health professional bodies such as the WHO, CDC, the Nigerian Federal Ministry of Health and the United Nations Children's Fund (UNICEF). A total of 103 articles were reviewed and 78 were found to contain information relevant to the study. LF remains an endemic disease of public health concern in the West Africa region, and in the rest of the world as cases have been imported into non-endemic regions as well. Currently, there are no approved vaccines or therapeutics for the treatment of Lassa mammarenavirus (LASV) infection. There are, however, off-label therapeutics being used (ribavirin and convalescent plasma) whose efficacy is suboptimal. Research is still ongoing on possible therapeutic options and drug repurposing of therapeutic agents currently in use for other clinical conditions. Considered therapeutic options include favipiravir, taribavirin, Arevirumab-3 and experimental drugs such as losmapimod, adamantyl diphenyl piperazine 3.3, Arbidol (umifenovir) and decanoyl-RRLL-chloromethyl ketone (dec-RRLL-CMK). Current treatments for LF are limited, hence the institution of mitigating measures to prevent infection is of utmost importance and should be prioritized, especially in endemic regions. Heightened searches for other therapeutic options with greater efficacy and lower toxicity are still ongoing, as well as for vaccines as the absence of these classifies the disease as a priority disease of high public health impact.
Collapse
Affiliation(s)
| | - Olumuyiwa John Fasipe
- Department of Pharmacology and Therapeutics, University of Medical Sciences, Ondo, Nigeria
| | | | - Olalekan Aliu Olatunji
- Department of Medical Microbiology and Parasitology, University College Hospital, Ibadan, Nigeria
| |
Collapse
|
9
|
Lassa virus glycoprotein complex review: insights into its unique fusion machinery. Biosci Rep 2022; 42:230708. [PMID: 35088070 PMCID: PMC8844875 DOI: 10.1042/bsr20211930] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/24/2022] [Accepted: 01/26/2022] [Indexed: 11/17/2022] Open
Abstract
Lassa virus (LASV), an arenavirus endemic to West Africa, causes Lassa fever—a lethal hemorrhagic fever. Entry of LASV into the host cell is mediated by the glycoprotein complex (GPC), which is the only protein located on the viral surface and comprises three subunits: glycoprotein 1 (GP1), glycoprotein 2 (GP2), and a stable signal peptide (SSP). The LASV GPC is a class one viral fusion protein, akin to those found in viruses such as human immunodeficiency virus (HIV), influenza, Ebola virus (EBOV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). These viruses are enveloped and utilize membrane fusion to deliver their genetic material to the host cell. Like other class one fusion proteins, LASV-mediated membrane fusion occurs through an orchestrated sequence of conformational changes in its GPC. The receptor-binding subunit, GP1, first engages with a host cell receptor then undergoes a unique receptor switch upon delivery to the late endosome. The acidic pH and change in receptor result in the dissociation of GP1, exposing the fusion subunit, GP2, such that fusion can occur. These events ultimately lead to the formation of a fusion pore so that the LASV genetic material is released into the host cell. Interestingly, the mature GPC retains its SSP as a third subunit—a feature that is unique to arenaviruses. Additionally, the fusion domain contains two separate fusion peptides, instead of a standard singular fusion peptide. Here, we give a comprehensive review of the LASV GPC components and their unusual features.
Collapse
|
10
|
Zhu X, Liu Y, Guo J, Cao J, Wang Z, Xiao G, Wang W. Effects of N-Linked Glycan on Lassa Virus Envelope Glycoprotein Cleavage, Infectivity, and Immune Response. Virol Sin 2021; 36:774-783. [PMID: 33689141 PMCID: PMC7945000 DOI: 10.1007/s12250-021-00358-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 01/13/2021] [Indexed: 11/29/2022] Open
Abstract
Lassa virus (LASV) belongs to the Mammarenavirus genus (family Arenaviridae) and causes severe hemorrhagic fever in humans. The glycoprotein complex (GPC) contains eleven N-linked glycans that play essential roles in GPC functionalities such as cleavage, transport, receptor recognition, epitope shielding, and immune response. We used three mutagenesis strategies (asparagine to glutamine, asparagine to alanine, and serine/tyrosine to alanine mutants) to abolish individual glycan chain on GPC and found that all the three strategies led to cleavage inefficiency on the 2nd (N89), 5th (N119), or 8th (N365) glycosylation motif. To evaluate N to Q mutagenesis for further research, it was found that deletion of the 2nd (N89Q) or 8th (N365Q) glycan completely inhibited the transduction efficiency of pseudotyped particles. We further investigated the role of individual glycan on GPC-mediated immune response by DNA immunization of mice. Deletion of the individual 1st (N79Q), 3rd (N99Q), 5th (N119Q), or 6th (N167Q) glycan significantly enhanced the proportion of effector CD4+ cells, whereas deletion of the 1st (N79Q), 2nd (N89Q), 3rd (N99Q), 4th (N109Q), 5th (N119Q), 6th (N167Q), or 9th (N373Q) glycan enhanced the proportion of CD8+ effector T cells. Deletion of specific glycan improves the Th1-type immune response, and abolishment of glycan on GPC generally increases the antibody titer to the glycan-deficient GPC. However, the antibodies from either the mutant or WT GPC-immunized mice show little neutralization effect on wild-type LASV. The glycan residues on GPC provide an immune shield for the virus, and thus represent a target for the design and development of a vaccine.
Collapse
Affiliation(s)
- Xueqin Zhu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.,University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Yang Liu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Jiao Guo
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.,University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Junyuan Cao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.,University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Zonglin Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.,University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Gengfu Xiao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.,University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Wei Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China. .,University of the Chinese Academy of Sciences, Beijing, 100049, China.
| |
Collapse
|
11
|
Koma T, Huang C, Coscia A, Hallam S, Manning JT, Maruyama J, Walker AG, Miller M, Smith JN, Patterson M, Abraham J, Paessler S. Glycoprotein N-linked glycans play a critical role in arenavirus pathogenicity. PLoS Pathog 2021; 17:e1009356. [PMID: 33647064 PMCID: PMC7951981 DOI: 10.1371/journal.ppat.1009356] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 03/11/2021] [Accepted: 02/03/2021] [Indexed: 12/15/2022] Open
Abstract
Several arenaviruses cause hemorrhagic fevers in humans with high case fatality rates. A vaccine named Candid#1 is available only against Junin virus (JUNV) in Argentina. Specific N-linked glycans on the arenavirus surface glycoprotein (GP) mask important epitopes and help the virus evade antibody responses. However the role of GPC glycans in arenavirus pathogenicity is largely unclear. In a lethal animal model of hemorrhagic fever-causing Machupo virus (MACV) infection, we found that a chimeric MACV with the ectodomain of GPC from Candid#1 vaccine was partially attenuated. Interestingly, mutations resulting in acquisition of N-linked glycans at GPC N83 and N166 frequently occurred in late stages of the infection. These glycosylation sites are conserved in the GPC of wild-type MACV, indicating that this is a phenotypic reversion for the chimeric MACV to gain those glycans crucial for infection in vivo. Further studies indicated that the GPC mutant viruses with additional glycans became more resistant to neutralizing antibodies and more virulent in animals. On the other hand, disruption of these glycosylation sites on wild-type MACV GPC rendered the virus substantially attenuated in vivo and also more susceptible to antibody neutralization, while loss of these glycans did not affect virus growth in cultured cells. We also found that MACV lacking specific GPC glycans elicited higher levels of neutralizing antibodies against wild-type MACV. Our findings revealed the critical role of specific glycans on GPC in arenavirus pathogenicity and have important implications for rational design of vaccines against this group of hemorrhagic fever-causing viruses. Several arenaviruses cause severe hemorrhagic fevers in humans. The only vaccine against arenavirus infections is Candid#1, a live attenuated vaccine against Argentine hemorrhagic fever. So far, we have successfully attenuated additional one of the arenaviruses, Machupo virus, the causative agent of Bolivian hemorrhagic fever. Unraveling this attenuation mechanism might help the development of live-attenuated vaccines for other arenaviruses. In this study, we revealed that the specific glycans of the viral glycoproteins play an important role in pathogenicity in vivo. The glycans facilitate the virus to evade neutralizing antibodies. This study would contribute to the development of arenavirus vaccine candidates.
Collapse
Affiliation(s)
- Takaaki Koma
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Cheng Huang
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Adrian Coscia
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Steven Hallam
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - John T. Manning
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Junki Maruyama
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Aida G. Walker
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Milagros Miller
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Jeanon N. Smith
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Michael Patterson
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Jonathan Abraham
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Slobodan Paessler
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
- * E-mail:
| |
Collapse
|
12
|
Hastie KM, Cross RW, Harkins SS, Zandonatti MA, Koval AP, Heinrich ML, Rowland MM, Robinson JE, Geisbert TW, Garry RF, Branco LM, Saphire EO. Convergent Structures Illuminate Features for Germline Antibody Binding and Pan-Lassa Virus Neutralization. Cell 2020; 178:1004-1015.e14. [PMID: 31398326 DOI: 10.1016/j.cell.2019.07.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 05/01/2019] [Accepted: 07/12/2019] [Indexed: 01/12/2023]
Abstract
Lassa virus (LASV) causes hemorrhagic fever and is endemic in West Africa. Protective antibody responses primarily target the LASV surface glycoprotein (GPC), and GPC-B competition group antibodies often show potent neutralizing activity in humans. However, which features confer potent and broadly neutralizing antibody responses is unclear. Here, we compared three crystal structures of LASV GPC complexed with GPC-B antibodies of varying neutralization potency. Each GPC-B antibody recognized an overlapping epitope involved in binding of two adjacent GPC monomers and preserved the prefusion trimeric conformation. Differences among GPC-antibody interactions highlighted specific residues that enhance neutralization. Using structure-guided amino acid substitutions, we increased the neutralization potency and breadth of these antibodies to include all major LASV lineages. The ability to define antibody residues that allow potent and broad neutralizing activity, together with findings from analyses of inferred germline precursors, is critical to develop potent therapeutics and for vaccine design and assessment.
Collapse
Affiliation(s)
- Kathryn M Hastie
- La Jolla Institute for Immunology, La Jolla, CA, USA; Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA
| | - Robert W Cross
- University of Texas Medical Branch, Galveston National Laboratory, Galveston, TX, USA
| | - Stephanie S Harkins
- La Jolla Institute for Immunology, La Jolla, CA, USA; Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA
| | - Michelle A Zandonatti
- La Jolla Institute for Immunology, La Jolla, CA, USA; Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA
| | | | | | | | - James E Robinson
- Department of Pediatrics, School of Medicine, Tulane University, New Orleans, LA, USA
| | - Thomas W Geisbert
- University of Texas Medical Branch, Galveston National Laboratory, Galveston, TX, USA
| | - Robert F Garry
- Zalgen Labs, Germantown, MD, USA; Department of Microbiology and Immunology, Tulane University, New Orleans, LA, USA
| | | | - Erica Ollmann Saphire
- La Jolla Institute for Immunology, La Jolla, CA, USA; Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA; Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA.
| |
Collapse
|
13
|
Ibukun FI. Inter-Lineage Variation of Lassa Virus Glycoprotein Epitopes: A Challenge to Lassa Virus Vaccine Development. Viruses 2020; 12:v12040386. [PMID: 32244402 PMCID: PMC7232328 DOI: 10.3390/v12040386] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 12/12/2022] Open
Abstract
Lassa virus (LASV), which causes considerable morbidity and mortality annually, has a high genetic diversity across West Africa. LASV glycoprotein (GP) expresses this diversity, but most LASV vaccine candidates utilize only the Lineage IV LASV Josiah strain GP antigen as an immunogen and homologous challenge with Lineage IV LASV. In addition to the sequence variation amongst the LASV lineages, these lineages are also distinguished in their presentations. Inter-lineage variations within previously mapped B-cell and T-cell LASV GP epitopes and the breadth of protection in LASV vaccine/challenge studies were examined critically. Multiple alignments of the GP primary sequence of strains from each LASV lineage showed that LASV GP has diverging degrees of amino acid conservation within known epitopes among LASV lineages. Conformational B-cell epitopes spanning different sites in GP subunits were less impacted by LASV diversity. LASV GP diversity should influence the approach used for LASV vaccine design. Expression of LASV GP on viral vectors, especially in its prefusion configuration, has shown potential for protective LASV vaccines that can overcome LASV diversity. Advanced vaccine candidates should demonstrate efficacy against all LASV lineages for evidence of a pan-LASV vaccine.
Collapse
Affiliation(s)
- Francis Ifedayo Ibukun
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, 21201, MD, USA
| |
Collapse
|
14
|
Hastie KM, Zandonatti MA, Kleinfelter LM, Heinrich ML, Rowland MM, Chandran K, Branco LM, Robinson JE, Garry RF, Saphire EO. Structural basis for antibody-mediated neutralization of Lassa virus. Science 2017; 356:923-928. [PMID: 28572385 PMCID: PMC6007842 DOI: 10.1126/science.aam7260] [Citation(s) in RCA: 155] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 04/28/2017] [Indexed: 12/25/2022]
Abstract
The arenavirus Lassa causes severe hemorrhagic fever and a significant disease burden in West Africa every year. The glycoprotein, GPC, is the sole antigen expressed on the viral surface and the critical target for antibody-mediated neutralization. Here we present the crystal structure of the trimeric, prefusion ectodomain of Lassa GP bound to a neutralizing antibody from a human survivor at 3.2-angstrom resolution. The antibody extensively anchors two monomers together at the base of the trimer, and biochemical analysis suggests that it neutralizes by inhibiting conformational changes required for entry. This work illuminates pH-driven conformational changes in both receptor-binding and fusion subunits of Lassa virus, illustrates the unique assembly of the arenavirus glycoprotein spike, and provides a much-needed template for vaccine design against these threats to global health.
Collapse
Affiliation(s)
- Kathryn M Hastie
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Michelle A Zandonatti
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Lara M Kleinfelter
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | | | | | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | | | - James E Robinson
- Department of Pediatrics, School of Medicine, Tulane University, New Orleans, LA, USA
| | - Robert F Garry
- Zalgen Labs, Germantown, MD, USA
- Department of Microbiology and Immunology, Tulane University, New Orleans, LA, USA
| | - Erica Ollmann Saphire
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA.
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA
| |
Collapse
|
15
|
Wang W, Zhou Z, Zhang L, Wang S, Xiao G. Structure-function relationship of the mammarenavirus envelope glycoprotein. Virol Sin 2016; 31:380-394. [PMID: 27562602 DOI: 10.1007/s12250-016-3815-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 06/27/2016] [Indexed: 12/29/2022] Open
Abstract
Mammarenaviruses, including lethal pathogens such as Lassa virus and Junín virus, can cause severe hemorrhagic fever in humans. Entry is a key step for virus infection, which starts with binding of the envelope glycoprotein (GP) to receptors on target cells and subsequent fusion of the virus with target cell membranes. The GP precursor is synthesized as a polypeptide, and maturation occurs by two cleavage events, yielding a tripartite GP complex (GPC) formed by a stable signal peptide (SSP), GP1 and GP2. The unique retained SSP interacts with GP2 and plays essential roles in virion maturation and infectivity. GP1 is responsible for binding to the cell receptor, and GP2 is a class I fusion protein. The native structure of the tripartite GPC is unknown. GPC is critical for the receptor binding, membrane fusion and neutralization antibody recognition. Elucidating the molecular mechanisms underlining the structure-function relationship of the three subunits is the key for understanding their function and can facilitate novel avenues for combating virus infections. This review summarizes the basic aspects and recent research of the structure-function relationship of the three subunits. We discuss the structural basis of the receptor-binding domain in GP1, the interaction between SSP and GP2 and its role in virion maturation and membrane fusion, as well as the mechanism by which glycosylation stabilizes the GPC structure and facilitates immune evasion. Understanding the molecular mechanisms involved in these aspects will contribute to the development of novel vaccines and treatment strategies against mammarenaviruses infection.
Collapse
Affiliation(s)
- Wei Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
| | - Zheng Zhou
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Leike Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Shaobo Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Gengfu Xiao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| |
Collapse
|
16
|
Sommerstein R, Flatz L, Remy MM, Malinge P, Magistrelli G, Fischer N, Sahin M, Bergthaler A, Igonet S, ter Meulen J, Rigo D, Meda P, Rabah N, Coutard B, Bowden TA, Lambert PH, Siegrist CA, Pinschewer DD. Arenavirus Glycan Shield Promotes Neutralizing Antibody Evasion and Protracted Infection. PLoS Pathog 2015; 11:e1005276. [PMID: 26587982 PMCID: PMC4654586 DOI: 10.1371/journal.ppat.1005276] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 10/22/2015] [Indexed: 01/05/2023] Open
Abstract
Arenaviruses such as Lassa virus (LASV) can cause severe hemorrhagic fever in humans. As a major impediment to vaccine development, delayed and weak neutralizing antibody (nAb) responses represent a unifying characteristic of both natural infection and all vaccine candidates tested to date. To investigate the mechanisms underlying arenavirus nAb evasion we engineered several arenavirus envelope-chimeric viruses and glycan-deficient variants thereof. We performed neutralization tests with sera from experimentally infected mice and from LASV-convalescent human patients. NAb response kinetics in mice correlated inversely with the N-linked glycan density in the arenavirus envelope protein’s globular head. Additionally and most intriguingly, infection with fully glycosylated viruses elicited antibodies, which neutralized predominantly their glycan-deficient variants, both in mice and humans. Binding studies with monoclonal antibodies indicated that envelope glycans reduced nAb on-rate, occupancy and thereby counteracted virus neutralization. In infected mice, the envelope glycan shield promoted protracted viral infection by preventing its timely elimination by the ensuing antibody response. Thus, arenavirus envelope glycosylation impairs the protective efficacy rather than the induction of nAbs, and thereby prevents efficient antibody-mediated virus control. This immune evasion mechanism imposes limitations on antibody-based vaccination and convalescent serum therapy. Neutralizing antibodies (nAbs) represent a key principle of antiviral immunity. Protective vaccines aim at inducing nAbs to prevent viral infection, and infusion of nAbs in convalescent patient serum can offer a potent antiviral therapy. Certain viruses, however, have found ways to evade nAb control. Amongst them are high-risk pathogens of the arenavirus family such as Lassa virus (LASV), which is a frequent cause of hemorrhagic fever in West Africa. Here we unveil the molecular strategy by which arenaviruses escape antibody neutralization and avoid efficient immune control. We show that their surface is decorated with sugar moieties, serving to shield the virus against the neutralizing effect of the host’s antibodies. This immune evasion strategy differs from those described for other viruses, in which sugars impair primarily the induction of antibodies or allow for viral mutational escape. The arenavirus sugar coat renders the host nAb response inefficient and as a consequence thereof, the host fails to promptly control the infection. Our results offer a compelling explanation for the long history of failures in trying to make a nAb-based vaccine against LASV or in using convalescent serum for therapy. These mechanistic insights will support vaccine development efforts against arenaviruses such as LASV.
Collapse
Affiliation(s)
- Rami Sommerstein
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
- World Health Organization Collaborating Centre for Vaccine Immunology, University of Geneva, Geneva, Switzerland
| | - Lukas Flatz
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Melissa M. Remy
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
- Division of Experimental Virology, Department of Biomedicine, University of Basel, Basel, Switzerland
| | | | | | | | - Mehmet Sahin
- Division of Experimental Virology, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Andreas Bergthaler
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Sebastien Igonet
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale and CNRS UMR 3569 Virologie, Paris, France
| | - Jan ter Meulen
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | - Dorothée Rigo
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Paolo Meda
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Nadia Rabah
- AFMB, UMR7257 CNRS/Aix Marseille Université, Marseille, France
| | - Bruno Coutard
- AFMB, UMR7257 CNRS/Aix Marseille Université, Marseille, France
| | - Thomas A. Bowden
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Paul-Henri Lambert
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
- World Health Organization Collaborating Centre for Vaccine Immunology, University of Geneva, Geneva, Switzerland
| | - Claire-Anne Siegrist
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
- World Health Organization Collaborating Centre for Vaccine Immunology, University of Geneva, Geneva, Switzerland
| | - Daniel D. Pinschewer
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
- World Health Organization Collaborating Centre for Vaccine Immunology, University of Geneva, Geneva, Switzerland
- Division of Experimental Virology, Department of Biomedicine, University of Basel, Basel, Switzerland
- * E-mail:
| |
Collapse
|
17
|
Murine Antibody Responses to Cleaved Soluble HIV-1 Envelope Trimers Are Highly Restricted in Specificity. J Virol 2015; 89:10383-98. [PMID: 26246566 DOI: 10.1128/jvi.01653-15] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 07/28/2015] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED Generating neutralizing antibodies (nAbs) is a major goal of many current HIV-1 vaccine efforts. To be of practical value, these nAbs must be both potent and cross-reactive in order to be capable of preventing the transmission of the highly diverse and generally neutralization resistant (Tier-2) HIV-1 strains that are in circulation. The HIV-1 envelope glycoprotein (Env) spike is the only target for nAbs. To explore whether Tier-2 nAbs can be induced by Env proteins, we immunized conventional mice with soluble BG505 SOSIP.664 trimers that mimic the native Env spike. Here, we report that it is extremely difficult for murine B cells to recognize the Env epitopes necessary for inducing Tier-2 nAbs. Thus, while trimer-immunized mice raised Env-binding IgG Abs and had high-quality T follicular helper (Tfh) cell and germinal center (GC) responses, they did not make BG505.T332N nAbs. Epitope mapping studies showed that Ab responses in mice were specific to areas near the base of the soluble trimer. These areas are not well shielded by glycans and likely are occluded on virions, which is consistent with the lack of BG505.T332N nAbs. These data inform immunogen design and suggest that it is useful to obscure nonneutralizing epitopes presented on the base of soluble Env trimers and that the glycan shield of well-formed HIV Env trimers is virtually impenetrable for murine B cell receptors (BCRs). IMPORTANCE Human HIV vaccine efficacy trials have not generated meaningful neutralizing antibodies to circulating HIV strains. One possible hindrance has been the lack of immunogens that properly mimic the native conformation of the HIV envelope trimer protein. Here, we tested the first generation of soluble, native-like envelope trimer immunogens in a conventional mouse model. We attempted to generate neutralizing antibodies to neutralization-resistant circulating HIV strains. Various vaccine strategies failed to induce neutralizing antibodies to a neutralization-resistant HIV strain. Further analysis revealed that mouse antibodies targeted areas near the bottom of the soluble envelope trimers. These areas are not easily accessible on the HIV virion due to occlusion by the viral membrane and may have resulted from an absence of glycan shielding. Our results suggest that obscuring the bottom of soluble envelope trimers is a useful strategy to reduce antibody responses to epitopes that are not useful for virus neutralization.
Collapse
|
18
|
Crystal structure of Venezuelan hemorrhagic fever virus fusion glycoprotein reveals a class 1 postfusion architecture with extensive glycosylation. J Virol 2013; 87:13070-5. [PMID: 24049182 PMCID: PMC3838125 DOI: 10.1128/jvi.02298-13] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Guanarito virus (GTOV) is an emergent and deadly pathogen. We present the crystal structure of the glycosylated GTOV fusion glycoprotein to 4.1-Å resolution in the postfusion conformation. Our structure reveals a classical six-helix bundle and presents direct verification that New World arenaviruses exhibit class I viral membrane fusion machinery. The structure provides visualization of an N-linked glycocalyx coat, and consideration of glycan dynamics reveals extensive coverage of the underlying protein surface, following virus-host membrane fusion.
Collapse
|
19
|
Perforin deficiency impairs a critical immunoregulatory loop involving murine CD8(+) T cells and dendritic cells. Blood 2013; 121:5184-91. [PMID: 23660960 DOI: 10.1182/blood-2013-04-495309] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Humans and mice with impaired perforin-dependent cytotoxic function may develop excessive T-cell activation and the fatal disorder hemophagocytic lymphohistiocytosis (HLH) after infection. Though cytotoxic lymphocytes can kill antigen-presenting cells, the physiological mechanism of perforin-mediated immune regulation has never been demonstrated in a disease-relevant context. We used a murine model of HLH to examine how perforin controls immune activation, and we have defined a feedback loop that is critical for immune homeostasis. This endogenous feedback loop involves perforin-dependent elimination of rare, antigen-presenting dendritic cells (DCs) by CD8(+) T cells and has a dominant influence on the magnitude of T-cell activation after viral infection. Antigen presentation by a minor fraction of DCs persisted in T-cell- or perforin-deficient animals and continued to drive T-cell activation well beyond initial priming in the latter animals. Depletion of DCs or transfer of perforin-sufficient T cells dampened endogenous DC antigen presentation and T-cell activation, demonstrating a reciprocal relationship between perforin in CD8(+) T cells and DC function. Thus, selective cytotoxic "pruning" of DC populations by CD8(+) T cells limits T-cell activation and protects against the development of HLH and potentially other immunopathological conditions.
Collapse
|