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Lipskij A, Arbeitman C, Rojas P, Ojeda-May P, Garcia ME. Dramatic Differences between the Structural Susceptibility of the S1 Pre- and S2 Postfusion States of the SARS-CoV-2 Spike Protein to External Electric Fields Revealed by Molecular Dynamics Simulations. Viruses 2023; 15:2405. [PMID: 38140646 PMCID: PMC10748067 DOI: 10.3390/v15122405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/30/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
In its prefusion state, the SARS-CoV-2 spike protein (similarly to other class I viral fusion proteins) is metastable, which is considered to be an important feature for optimizing or regulating its functions. After the binding process of its S1 subunit (S1) with ACE2, the spike protein (S) undergoes a dramatic conformational change where S1 splits from the S2 subunit, which then penetrates the membrane of the host cell, promoting the fusion of the viral and cell membranes. This results in the infection of the host cell. In a previous work, we showed-using large-scale molecular dynamics simulations-that the application of external electric fields (EFs) induces drastic changes and damage in the receptor-binding domain (RBD) of the wild-type spike protein, as well of the Alpha, Beta, and Gamma variants, leaving a structure which cannot be recognized anymore by ACE2. In this work, we first extend the study to the Delta and Omicron variants and confirm the high sensitivity and extreme vulnerability of the RBD of the prefusion state of S to moderate EF (as weak as 104 V/m), but, more importantly, we also show that, in contrast, the S2 subunit of the postfusion state of the spike protein does not suffer structural damage even if electric field intensities four orders of magnitude higher are applied. These results provide a solid scientific basis to confirm the connection between the prefusion-state metastability of the SARS-CoV-2 spike protein and its susceptibility to be damaged by EF. After the virus docks to the ACE2 receptor, the stable and robust postfusion conformation develops, which exhibits a similar resistance to EF (damage threshold higher than 108 V/m) like most globular proteins.
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Affiliation(s)
- Alexander Lipskij
- Theoretical Physics and Center of Interdisciplinary Nanostructure Science and Technology, FB10, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany; (A.L.); (C.A.); (P.R.)
| | - Claudia Arbeitman
- Theoretical Physics and Center of Interdisciplinary Nanostructure Science and Technology, FB10, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany; (A.L.); (C.A.); (P.R.)
- CONICET Consejo Nacional de Investigaciones Científicas y Técnicas, Godoy Cruz 2290, Buenos Aires C1425FQB, Argentina
- GIBIO-Universidad Tecnológica Nacional-Facultad Regional Buenos Aires, Medrano 951, Buenos Aires C1179AAQ, Argentina
| | - Pablo Rojas
- Theoretical Physics and Center of Interdisciplinary Nanostructure Science and Technology, FB10, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany; (A.L.); (C.A.); (P.R.)
| | - Pedro Ojeda-May
- High Performance Computing Center North (HPC2N), Umeå University, S-90187 Umeå, Sweden;
| | - Martin E. Garcia
- Theoretical Physics and Center of Interdisciplinary Nanostructure Science and Technology, FB10, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany; (A.L.); (C.A.); (P.R.)
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Engler M, Albers D, Von Maltitz P, Groß R, Münch J, Cirstea IC. ACE2-EGFR-MAPK signaling contributes to SARS-CoV-2 infection. Life Sci Alliance 2023; 6:e202201880. [PMID: 37402592 PMCID: PMC10320016 DOI: 10.26508/lsa.202201880] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 06/20/2023] [Accepted: 06/21/2023] [Indexed: 07/06/2023] Open
Abstract
SARS-CoV-2 triggered the most severe pandemic of recent times. To enter into a host cell, SARS-CoV-2 binds to the angiotensin-converting enzyme 2 (ACE2). However, subsequent studies indicated that other cell membrane receptors may act as virus-binding partners. Among these receptors, the epidermal growth factor receptor (EGFR) was hypothesized not only as a spike protein binder, but also to be activated in response to SARS-CoV-2. In our study, we aim at dissecting EGFR activation and its major downstream signaling pathway, the mitogen-activated signaling pathway (MAPK), in SARS-CoV-2 infection. Here, we demonstrate the activation of EGFR-MAPK signaling axis by the SARS-CoV-2 spike protein and we identify a yet unknown cross talk between ACE2 and EGFR that regulated ACE2 abundance and EGFR activation and subcellular localization, respectively. By inhibiting the EGFR-MAPK activation, we observe a reduced infection with either spike-pseudotyped particles or authentic SARS-CoV-2, thus indicating that EGFR serves as a cofactor and the activation of EGFR-MAPK contributes to SARS-CoV-2 infection.
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Affiliation(s)
- Melanie Engler
- Institute of Comparative Molecular Endocrinology, Ulm University, Ulm, Germany
| | - Dan Albers
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Pascal Von Maltitz
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Rüdiger Groß
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Jan Münch
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
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Ardicli O, Carli KT, Satitsuksanoa P, Dreher A, Cusini A, Hutter S, Mirer D, Rückert B, Jonsdottir H, Weber B, Cervia C, Akdis M, Boyman O, Eggel A, Brüggen M, Akdis C, van de Veen W. Exposure to avian coronavirus vaccines is associated with increased levels of SARS-CoV-2-cross-reactive antibodies. Allergy 2022; 77:3648-3662. [PMID: 35869837 PMCID: PMC9467642 DOI: 10.1111/all.15441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 07/01/2022] [Accepted: 07/09/2022] [Indexed: 01/28/2023]
Abstract
BACKGROUND Although avian coronavirus infectious bronchitis virus (IBV) and SARS-CoV-2 belong to different genera of the Coronaviridae family, exposure to IBV may result in the development of cross-reactive antibodies to SARS-CoV-2 due to homologous epitopes. We aimed to investigate whether antibody responses to IBV cross-react with SARS-CoV-2 in poultry farm personnel who are occupationally exposed to aerosolized IBV vaccines. METHODS We analyzed sera from poultry farm personnel, COVID-19 patients, and pre-pandemic controls. IgG levels against the SARS-CoV-2 antigens S1, RBD, S2, and N and peptides corresponding to the SARS-CoV-2 ORF3a, N, and S proteins as well as whole virus antigens of the four major S1-genotypes 4/91, IS/1494/06, M41, and D274 of IBV were investigated by in-house ELISAs. Moreover, live-virus neutralization test (VNT) was performed. RESULTS A subgroup of poultry farm personnel showed elevated levels of specific IgG for all tested SARS-CoV-2 antigens compared with pre-pandemic controls. Moreover, poultry farm personnel, COVID-19 patients, and pre-pandemic controls showed specific IgG antibodies against IBV strains. These antibody titers were higher in long-term vaccine implementers. We observed a strong correlation between IBV-specific IgG and SARS-CoV-2 S1-, RBD-, S2-, and N-specific IgG in poultry farm personnel compared with pre-pandemic controls and COVID-19 patients. However, no neutralization was observed for these cross-reactive antibodies from poultry farm personnel using the VNT. CONCLUSION We report here for the first time the detection of cross-reactive IgG antibodies against SARS-CoV-2 antigens in humans exposed to IBV vaccines. These findings may be useful for further studies on the adaptive immunity against COVID-19.
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Affiliation(s)
- Ozge Ardicli
- Swiss Institute of Allergy and Asthma Research (SIAF)University of ZurichDavosSwitzerland
- Department of Microbiology, Faculty of Veterinary MedicineBursa Uludag UniversityBursaTurkey
| | - K. Tayfun Carli
- Department of Microbiology, Faculty of Veterinary MedicineBursa Uludag UniversityBursaTurkey
| | | | - Anita Dreher
- Christine Kühne‐Center for Allergy Research and Education (CK‐CARE)DavosSwitzerland
| | - Alexia Cusini
- Division of Infectious DiseasesCantonal Hospital of GrisonsChurSwitzerland
| | - Sandra Hutter
- Central LaboratoryCantonal Hospital of GrisonsChurSwitzerland
| | - David Mirer
- Swiss Institute of Allergy and Asthma Research (SIAF)University of ZurichDavosSwitzerland
| | - Beate Rückert
- Swiss Institute of Allergy and Asthma Research (SIAF)University of ZurichDavosSwitzerland
| | - Hulda R. Jonsdottir
- Spiez Laboratory, Federal Office for Civil ProtectionSpiezSwitzerland
- Department of Rheumatology, Immunology, and AllergologyInselspital University HospitalBernSwitzerland
- Department of BioMedical ResearchUniversity of BernBernSwitzerland
| | - Benjamin Weber
- Spiez Laboratory, Federal Office for Civil ProtectionSpiezSwitzerland
| | - Carlo Cervia
- Department of ImmunologyUniversity Hospital ZurichZurichSwitzerland
| | - Mubeccel Akdis
- Swiss Institute of Allergy and Asthma Research (SIAF)University of ZurichDavosSwitzerland
| | - Onur Boyman
- Department of ImmunologyUniversity Hospital ZurichZurichSwitzerland
- Faculty of MedicineUniversity of ZurichZurichSwitzerland
| | - Alexander Eggel
- Department of Rheumatology, Immunology, and AllergologyInselspital University HospitalBernSwitzerland
- Department of BioMedical ResearchUniversity of BernBernSwitzerland
| | - Marie‐Charlotte Brüggen
- Christine Kühne‐Center for Allergy Research and Education (CK‐CARE)DavosSwitzerland
- Faculty of MedicineUniversity of ZurichZurichSwitzerland
- Department of DermatologyUniversity Hospital ZurichZurichSwitzerland
| | - Cezmi A. Akdis
- Swiss Institute of Allergy and Asthma Research (SIAF)University of ZurichDavosSwitzerland
- Christine Kühne‐Center for Allergy Research and Education (CK‐CARE)DavosSwitzerland
| | - Willem van de Veen
- Swiss Institute of Allergy and Asthma Research (SIAF)University of ZurichDavosSwitzerland
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Goyal R, Gautam RK, Chopra H, Dubey AK, Singla RK, Rayan RA, Kamal MA. Comparative highlights on MERS-CoV, SARS-CoV-1, SARS-CoV-2, and NEO-CoV. EXCLI JOURNAL 2022; 21:1245-1272. [PMID: 36483910 PMCID: PMC9727256 DOI: 10.17179/excli2022-5355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 09/23/2022] [Indexed: 01/25/2023]
Abstract
The severe acute respiratory syndrome (SARS-CoV, now SARS-CoV-1), middle east respiratory syndrome (MERS-CoV), Neo-CoV, and 2019 novel coronavirus (SARS-CoV-2/COVID-19) are the most notable coronaviruses, infecting the number of people worldwide by targeting the respiratory system. All these viruses are of zoonotic origin, predominantly from bats which are one of the natural reservoir hosts for coronaviruses. Thus, the major goal of our review article is to compare and contrast the characteristics and attributes of these coronaviruses. The SARS-CoV-1, MERS-CoV, and COVID-19 have many viral similarities due to their classification, they are not genetically related. COVID-19 shares approximately 79 % of its genome with SARS-CoV-1 and about 50 % with MERS-CoV. The shared receptor protein, ACE2 exhibit the most striking genetic similarities between SARS-CoV-1 and SARS-CoV-2. SARS-CoV primarily replicates in the epithelial cells of the respiratory system, but it may also affect macrophages, monocytes, activated T cells, and dendritic cells. MERS-CoV not only infects and replicates inside the epithelial and immune cells, but it may lyse them too, which is one of the common reasons for MERS's higher mortality rate. The details of infections caused by SARS-CoV-2 and lytic replication mechanisms in host cells are currently mysterious. In this review article, we will discuss the comparative highlights of SARS-CoV-1, MERS-CoV, SARS-CoV-2, and Neo-CoV, concerning their structural features, morphological characteristics, sources of virus origin and their evolutionary transitions, infection mechanism, computational study approaches, pathogenesis and their severity towards several diseases, possible therapeutic approaches, and preventive measures.
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Affiliation(s)
- Rajat Goyal
- MM College of Pharmacy, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala, Haryana, India,MM School of Pharmacy, Maharishi Markandeshwar University, Sadopur-Ambala, India
| | - Rupesh K. Gautam
- Department of Pharmacology, Indore Institute of Pharmacy, Rau, Indore, India-453331,*To whom correspondence should be addressed: Rupesh K. Gautam, Department of Pharmacology, Indore Institute of Pharmacy, IIST Campus, Opposite IIM Indore, Rau-Pithampur Road, Indore – 453331 (M.P.), India; Tel.: +91 9413654324, E-mail:
| | - Hitesh Chopra
- Chitkara College of Pharmacy, Chitkara University, Punjab, India-140401
| | | | - Rajeev K. Singla
- Institutes for Systems Genetics, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China,School of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Punjab-144411, India
| | - Rehab A. Rayan
- Department of Epidemiology, High Institute of Public Health, Alexandria University, 5422031, Egypt
| | - Mohammad Amjad Kamal
- Institutes for Systems Genetics, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China,King Fahd Medical Research Center, King Abdulaziz University, Saudi Arabia,Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, Bangladesh,Enzymoics, 7 Peterlee Place, Hebersham NSW 2770; Novel Global Community Educational Foundation, Australia
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Sha X, Li Y, Huang J, Zhou Q, Song X, Zhang B. Detection and molecular characteristics of canine coronavirus in Chengdu city, Southwest China from 2020 to 2021. Microb Pathog 2022; 166:105548. [DOI: 10.1016/j.micpath.2022.105548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/27/2022] [Accepted: 04/17/2022] [Indexed: 11/26/2022]
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Zandi M, Hosseini P, Soltani S, Rasooli A, Moghadami M, Nasimzadeh S, Behnezhad F. The role of lipids in the pathophysiology of coronavirus infections. Osong Public Health Res Perspect 2021; 12:278-285. [PMID: 34719219 PMCID: PMC8561023 DOI: 10.24171/j.phrp.2021.0153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 10/06/2021] [Indexed: 11/23/2022] Open
Abstract
Coronaviruses, which have been known to cause diseases in animals since the 1930s, utilize cellular components during their replication cycle. Lipids play important roles in viral infection, as coronaviruses target cellular lipids and lipid metabolism to modify their host cells to become an optimal environment for viral replication. Therefore, lipids can be considered as potential targets for the development of antiviral agents. This review provides an overview of the roles of cellular lipids in different stages of the life cycle of coronaviruses.
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Affiliation(s)
- Milad Zandi
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Clinical Virology, Tehran University of Medical Sciences, Tehran, Iran
| | - Parastoo Hosseini
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Clinical Virology, Tehran University of Medical Sciences, Tehran, Iran
| | - Saber Soltani
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Clinical Virology, Tehran University of Medical Sciences, Tehran, Iran
| | - Azadeh Rasooli
- Department of Biochemistry, Faculty of Sciences, Payame Noor University, Tehran, Iran
| | - Mona Moghadami
- Department of Medical Biotechnology, School of Medicine, Babol University of Medical Sciences, Babol, Iran
| | - Sepideh Nasimzadeh
- Department of Virology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Farzane Behnezhad
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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7
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The SARS-CoV-2 spike protein is vulnerable to moderate electric fields. Nat Commun 2021; 12:5407. [PMID: 34518528 PMCID: PMC8437970 DOI: 10.1038/s41467-021-25478-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 08/12/2021] [Indexed: 12/23/2022] Open
Abstract
Most of the ongoing projects aimed at the development of specific therapies and vaccines against COVID-19 use the SARS-CoV-2 spike (S) protein as the main target. The binding of the spike protein with the ACE2 receptor (ACE2) of the host cell constitutes the first and key step for virus entry. During this process, the receptor binding domain (RBD) of the S protein plays an essential role, since it contains the receptor binding motif (RBM), responsible for the docking to the receptor. So far, mostly biochemical methods are being tested in order to prevent binding of the virus to ACE2. Here we show, with the help of atomistic simulations, that external electric fields of easily achievable and moderate strengths can dramatically destabilise the S protein, inducing long-lasting structural damage. One striking field-induced conformational change occurs at the level of the recognition loop L3 of the RBD where two parallel beta sheets, believed to be responsible for a high affinity to ACE2, undergo a change into an unstructured coil, which exhibits almost no binding possibilities to the ACE2 receptor. We also show that these severe structural changes upon electric-field application also occur in the mutant RBDs corresponding to the variants of concern (VOC) B.1.1.7 (UK), B.1.351 (South Africa) and P.1 (Brazil). Remarkably, while the structural flexibility of S allows the virus to improve its probability of entering the cell, it is also the origin of the surprising vulnerability of S upon application of electric fields of strengths at least two orders of magnitude smaller than those required for damaging most proteins. Our findings suggest the existence of a clean physical method to weaken the SARS-CoV-2 virus without further biochemical processing. Moreover, the effect could be used for infection prevention purposes and also to develop technologies for in-vitro structural manipulation of S. Since the method is largely unspecific, it can be suitable for application to other mutations in S, to other proteins of SARS-CoV-2 and in general to membrane proteins of other virus types. The SARS-CoV-2 Spike protein is essential for viral infectivity and binds to the host receptor ACE2. Here, the authors present MD simulations of the Spike protein and its variants of concern and observe that the Spike protein is destabilised by moderate static electric fields, and undergoes field-induced conformational changes that hinder binding to ACE2.
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Bioactive Molecules Derived from Snake Venoms with Therapeutic Potential for the Treatment of Thrombo-Cardiovascular Disorders Associated with COVID-19. Protein J 2021; 40:799-841. [PMID: 34499333 PMCID: PMC8427918 DOI: 10.1007/s10930-021-10019-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2021] [Indexed: 01/08/2023]
Abstract
As expected, several new variants of Severe Acute Respiratory Syndrome-CoronaVirus-2 (SARS-CoV-2) emerged and have been detected around the world throughout this Coronavirus Disease of 2019 (COVID-19) pandemic. Currently, there is no specific developed drug against COVID-19 and the challenge of developing effective antiviral strategies based on natural agents with different mechanisms of action becomes an urgent need and requires identification of genetic differences among variants. Such data is used to improve therapeutics to combat SARS-CoV-2 variants. Nature is known to offer many biotherapeutics from animal venoms, algae and plant that have been historically used in traditional medicine. Among these bioresources, snake venom displays many bioactivities of interest such as antiviral, antiplatelet, antithrombotic, anti-inflammatory, antimicrobial and antitumoral. COVID-19 is a viral respiratory sickness due to SARS-CoV-2 which induces thrombotic disorders due to cytokine storm, platelet hyperactivation and endothelial dysfunction. This review aims to: (1) present an overview on the infection, the developed thrombo-inflammatory responses and mechanisms of induced thrombosis of COVID-19 compared to other similar pathogenesis; (2) underline the role of natural compounds such as anticoagulant, antiplatelet and thrombolytic agents; (3) investigate the management of coagulopathy related to COVID-19 and provide insight on therapeutic such as venom compounds. We also summarize the updated advances on antiviral proteins and peptides derived from snake venoms that could weaken coagulopathy characterizing COVID-19.
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Variants in ACE2; potential influences on virus infection and COVID-19 severity. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2021; 90:104773. [PMID: 33607284 PMCID: PMC7886638 DOI: 10.1016/j.meegid.2021.104773] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 02/08/2021] [Accepted: 02/12/2021] [Indexed: 02/07/2023]
Abstract
The third pandemic of coronavirus infection, called COVID-19 disease, was first detected in November 2019th. Various determinants of disease progression such as age, sex, virus mutations, comorbidity, lifestyle, host immune response, and genetic background variation have caused clinical variability of COVID-19. The causative agent of COVID-19 is an enveloped coronavirus named severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) that invades host cells using an endocytic pathway. The SARS-CoV-2 spike protein is the main viral protein that contributes to the fusion of the virus particle to the host cell through angiotensin-converting enzyme 2 (ACE2). The highly conserved expression of ACE2 is found in various animals, which indicates its pivotal physiological function. The ACE2 has a crucial role in vascular, renal, and myocardial physiology. Genetic factors contributing to the outcome of SARS-CoV-2 infection are unknown; however, variants in the specific sites of ACE2 gene could be regarded as a main genetic risk factor for COVID-19. Given that ACE2 is the main site for virus landing on host cells, the effect of amino acid sequences of ACE2 on host susceptibility to COVID-19 seems reasonable. It would likely have a substantial role in the occurrence of a wide range of clinical symptoms. Several ACE2 variants can affect the protein stability, influencing the interaction between spike protein and ACE2 through imposing conformational changes while some other variants are known to cause a decrease or an increase in the ligand-receptor affinity. The other variations are located at the proteolytic cleavage site, which can influence virus infection; because soluble ACE2 can act as a decoy receptor for virus and decrease virus intake by cell surface ACE2. Notably, polymorphisms of regulatory and non-coding regions such as promoter in ACE2, can play crucial role in different expression levels of ACE2 among different individuals. Many studies should be performed to investigate the involvement of ACE2 polymorphism with susceptibility to COVID-19. Herein, we discuss some reported associations between variants of ACE2 and COVID-19 in details. In addition, the mode of action of ACE2 and its role in SARS-CoV-2 infection are highlighted which is followed by addressing the effects of several ACE2 variants on its protein stability, viral tropism or ligand-receptor affinity, secondary and tertiary structure or protein conformation, proteolytic cleavage site, and finally inter-individual clinical variability in COVID-19. The polymorphisms of regulatory regions of ACE2 and their effect on expression levels of ACE2 are also provided in this review. Such studies can improve the prediction of the affinity of mutant ACE2 variations with spike protein, and help the biopharmaceutical industry to design effective approaches for recombinant hACE2 therapy and vaccination of COVID-19 disease.
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Wong NA, Saier MH. The SARS-Coronavirus Infection Cycle: A Survey of Viral Membrane Proteins, Their Functional Interactions and Pathogenesis. Int J Mol Sci 2021; 22:1308. [PMID: 33525632 PMCID: PMC7865831 DOI: 10.3390/ijms22031308] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 02/07/2023] Open
Abstract
Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is a novel epidemic strain of Betacoronavirus that is responsible for the current viral pandemic, coronavirus disease 2019 (COVID-19), a global health crisis. Other epidemic Betacoronaviruses include the 2003 SARS-CoV-1 and the 2009 Middle East Respiratory Syndrome Coronavirus (MERS-CoV), the genomes of which, particularly that of SARS-CoV-1, are similar to that of the 2019 SARS-CoV-2. In this extensive review, we document the most recent information on Coronavirus proteins, with emphasis on the membrane proteins in the Coronaviridae family. We include information on their structures, functions, and participation in pathogenesis. While the shared proteins among the different coronaviruses may vary in structure and function, they all seem to be multifunctional, a common theme interconnecting these viruses. Many transmembrane proteins encoded within the SARS-CoV-2 genome play important roles in the infection cycle while others have functions yet to be understood. We compare the various structural and nonstructural proteins within the Coronaviridae family to elucidate potential overlaps and parallels in function, focusing primarily on the transmembrane proteins and their influences on host membrane arrangements, secretory pathways, cellular growth inhibition, cell death and immune responses during the viral replication cycle. We also offer bioinformatic analyses of potential viroporin activities of the membrane proteins and their sequence similarities to the Envelope (E) protein. In the last major part of the review, we discuss complement, stimulation of inflammation, and immune evasion/suppression that leads to CoV-derived severe disease and mortality. The overall pathogenesis and disease progression of CoVs is put into perspective by indicating several stages in the resulting infection process in which both host and antiviral therapies could be targeted to block the viral cycle. Lastly, we discuss the development of adaptive immunity against various structural proteins, indicating specific vulnerable regions in the proteins. We discuss current CoV vaccine development approaches with purified proteins, attenuated viruses and DNA vaccines.
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Affiliation(s)
- Nicholas A. Wong
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Milton H. Saier
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
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Papa G, Mallery DL, Albecka A, Welch LG, Cattin-Ortolá J, Luptak J, Paul D, McMahon HT, Goodfellow IG, Carter A, Munro S, James LC. Furin cleavage of SARS-CoV-2 Spike promotes but is not essential for infection and cell-cell fusion. PLoS Pathog 2021; 17:e1009246. [PMID: 33493182 PMCID: PMC7861537 DOI: 10.1371/journal.ppat.1009246] [Citation(s) in RCA: 212] [Impact Index Per Article: 70.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 02/04/2021] [Accepted: 12/18/2020] [Indexed: 12/30/2022] Open
Abstract
Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) infects cells by binding to the host cell receptor ACE2 and undergoing virus-host membrane fusion. Fusion is triggered by the protease TMPRSS2, which processes the viral Spike (S) protein to reveal the fusion peptide. SARS-CoV-2 has evolved a multibasic site at the S1-S2 boundary, which is thought to be cleaved by furin in order to prime S protein for TMPRSS2 processing. Here we show that CRISPR-Cas9 knockout of furin reduces, but does not prevent, the production of infectious SARS-CoV-2 virus. Comparing S processing in furin knockout cells to multibasic site mutants reveals that while loss of furin substantially reduces S1-S2 cleavage it does not prevent it. SARS-CoV-2 S protein also mediates cell-cell fusion, potentially allowing virus to spread virion-independently. We show that loss of furin in either donor or acceptor cells reduces, but does not prevent, TMPRSS2-dependent cell-cell fusion, unlike mutation of the multibasic site that completely prevents syncytia formation. Our results show that while furin promotes both SARS-CoV-2 infectivity and cell-cell spread it is not essential, suggesting furin inhibitors may reduce but not abolish viral spread.
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Affiliation(s)
- Guido Papa
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Donna L. Mallery
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Anna Albecka
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Lawrence G. Welch
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Jérôme Cattin-Ortolá
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Jakub Luptak
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - David Paul
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Harvey T. McMahon
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Ian G. Goodfellow
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke’s Hospital, Hills Road, Cambridge, United Kingdom
| | - Andrew Carter
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Sean Munro
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Leo C. James
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
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12
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Vahedifard F, Chakravarthy K. Nanomedicine for COVID-19: the role of nanotechnology in the treatment and diagnosis of COVID-19. EMERGENT MATERIALS 2021; 4:75-99. [PMID: 33615140 PMCID: PMC7881345 DOI: 10.1007/s42247-021-00168-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 01/19/2021] [Indexed: 05/12/2023]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the recent outbreak of coronavirus 2019 (COVID-19). Although nearly two decades have passed since the emergence of pandemics such as SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV), no effective drug against the CoV family has yet been approved, so there is a need to find newer therapeutic targets. Currently, simultaneous research across the globe is being performed to discover efficient vaccines or drugs, including both conventional therapies used to treat previous similar diseases and emerging therapies like nanomedicine. Nanomedicine has already proven its value through its application drug delivery and nanosensors in other diseases. Nanomedicine and its components can play an important role in various stages of prevention, diagnosis, treatment, vaccination, and research related to COVID-19. Nano-based antimicrobial technology can be integrated into personal equipment for the greater safety of healthcare workers and people. Various nanomaterials such as quantum dots can be used as biosensors to diagnose COVID-19. Nanotechnology offers benefits from the use of nanosystems, such as liposomes, polymeric and lipid nanoparticles, metallic nanoparticles, and micelles, for drug encapsulation, and facilitates the improvement of pharmacological drug properties. Antiviral functions for nanoparticles can target the binding, entry, replication, and budding of COVID-19. The toxicity-related inorganic nanoparticles are one of the limiting factors of its use that should be further investigated and modified. In this review, we are going to discuss nanomedicine options for COVID-19 management, similar applications for related viral diseases, and their gap of knowledge.
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Affiliation(s)
- Farzan Vahedifard
- Altman Clinical and Translational Research Institute, University of California San Diego Health Center, San Diego, CA USA
| | - Krishnan Chakravarthy
- Division of Pain Medicine, Department of Anesthesiology, University of California San Diego Health Center, 9400 Campus Point Dr, La Jolla, San Diego, CA USA
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13
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Khavinson V, Linkova N, Dyatlova A, Kuznik B, Umnov R. Peptides: Prospects for Use in the Treatment of COVID-19. Molecules 2020; 25:E4389. [PMID: 32987757 PMCID: PMC7583759 DOI: 10.3390/molecules25194389] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 01/08/2023] Open
Abstract
There is a vast practice of using antimalarial drugs, RAS inhibitors, serine protease inhibitors, inhibitors of the RNA-dependent RNA polymerase of the virus and immunosuppressants for the treatment of the severe form of COVID-19, which often occurs in patients with chronic diseases and older persons. Currently, the clinical efficacy of these drugs for COVID-19 has not been proven yet. Side effects of antimalarial drugs can worsen the condition of patients and increase the likelihood of death. Peptides, given their physiological mechanism of action, have virtually no side effects. Many of them are geroprotectors and can be used in patients with chronic diseases. Peptides may be able to prevent the development of the pathological process during COVID-19 by inhibiting SARS-CoV-2 virus proteins, thereby having immuno- and bronchoprotective effects on lung cells, and normalizing the state of the hemostasis system. Immunomodulators (RKDVY, EW, KE, AEDG), possessing a physiological mechanism of action at low concentrations, appear to be the most promising group among the peptides. They normalize the cytokines' synthesis and have an anti-inflammatory effect, thereby preventing the development of disseminated intravascular coagulation, acute respiratory distress syndrome and multiple organ failure.
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Affiliation(s)
- Vladimir Khavinson
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (V.K.); (A.D.); (R.U.)
- The Group of Peptide Regulation of Aging, Pavlov Institute of Physiology of RAS, 199034 St. Petersburg, Russia
| | - Natalia Linkova
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (V.K.); (A.D.); (R.U.)
- Department of Therapy, Geriatry, and Anti-Aging Medicine, Academy of Postgraduate Education under FSBU FSCC of FMBA of Russia, 125310 Moscow, Russia
- Department of Medical and Biological Disciplines, Belgorod State University, 308015 Belgorod, Russia
| | - Anastasiia Dyatlova
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (V.K.); (A.D.); (R.U.)
| | - Boris Kuznik
- Department of the normal physiology, Chita State Medical Academy, 672000 Chita, Russia;
| | - Roman Umnov
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (V.K.); (A.D.); (R.U.)
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14
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Kim Y, Son K, Kim YS, Lee SY, Jheong W, Oem JK. Complete genome analysis of a SARS-like bat coronavirus identified in the Republic of Korea. Virus Genes 2019; 55:545-549. [PMID: 31076983 PMCID: PMC7089380 DOI: 10.1007/s11262-019-01668-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 04/30/2019] [Indexed: 01/05/2023]
Abstract
Bats have been widely known as natural reservoir hosts of zoonotic diseases, such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) caused by coronaviruses (CoVs). In the present study, we investigated the whole genomic sequence of a SARS-like bat CoV (16BO133) and found it to be 29,075 nt in length with a 40.9% G+C content. Phylogenetic analysis using amino acid sequences of the ORF 1ab and the spike gene showed that the bat coronavirus strain 16BO133 was grouped with the Beta-CoV lineage B and was closely related to the JTMC15 strain isolated from Rhinolophus ferrumequinum in China. However, 16BO133 was distinctly located in the phylogenetic topology of the human SARS CoV strain (Tor2). Interestingly, 16BO133 showed complete elimination of ORF8 regions induced by a frame shift of the stop codon in ORF7b. The lowest amino acid identity of 16BO133 was identified at the spike region among various ORFs. The spike region of 16BO133 showed 84.7% and 75.2% amino acid identity with Rf1 (SARS-like bat CoV) and Tor2 (human SARS CoV), respectively. In addition, the S gene of 16BO133 was found to contain the amino acid substitution of two critical residues (N479S and T487 V) associated with human infection. In conclusion, we firstly carried out whole genome characterization of the SARS-like bat coronavirus discovered in the Republic of Korea; however, it presumably has no human infectivity. However, continuous surveillance and genomic characterization of coronaviruses from bats are necessary due to potential risks of human infection induced by genetic mutation.
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Affiliation(s)
- Yongkwan Kim
- Environmental Health Research Department, National Institute of Environmental Research, Hwangyeong-ro 42, Seo-gu, Incheon, Republic of Korea.,Department of Veterinary Infectious Diseases, College of Veterinary Medicine, Chonbuk National University, Jeonju, Republic of Korea
| | - Kidong Son
- Environmental Health Research Department, National Institute of Environmental Research, Hwangyeong-ro 42, Seo-gu, Incheon, Republic of Korea
| | - Young-Sik Kim
- Department of Veterinary Infectious Diseases, College of Veterinary Medicine, Chonbuk National University, Jeonju, Republic of Korea
| | - Sook-Young Lee
- Department of Veterinary Infectious Diseases, College of Veterinary Medicine, Chonbuk National University, Jeonju, Republic of Korea
| | - Weonhwa Jheong
- Environmental Health Research Department, National Institute of Environmental Research, Hwangyeong-ro 42, Seo-gu, Incheon, Republic of Korea
| | - Jae-Ku Oem
- Department of Veterinary Infectious Diseases, College of Veterinary Medicine, Chonbuk National University, Jeonju, Republic of Korea.
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15
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Zhang SM, Liao Y, Neo TL, Lu Y, Liu DX, Vahlne A, Tam JP. Identification and application of self-binding zipper-like sequences in SARS-CoV spike protein. Int J Biochem Cell Biol 2018; 101:103-112. [PMID: 29800727 PMCID: PMC7108413 DOI: 10.1016/j.biocel.2018.05.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 05/03/2018] [Accepted: 05/21/2018] [Indexed: 12/15/2022]
Abstract
Self-binding peptides containing zipper-like sequences, such as the Leu/Ile zipper sequence within the coiled coil regions of proteins and the cross-β spine steric zippers within the amyloid-like fibrils, could bind to the protein-of-origin through homophilic sequence-specific zipper motifs. These self-binding sequences represent opportunities for the development of biochemical tools and/or therapeutics. Here, we report on the identification of a putative self-binding β-zipper-forming peptide within the severe acute respiratory syndrome-associated coronavirus spike (S) protein and its application in viral detection. Peptide array scanning of overlapping peptides covering the entire length of S protein identified 34 putative self-binding peptides of six clusters, five of which contained octapeptide core consensus sequences. The Cluster I consensus octapeptide sequence GINITNFR was predicted by the Eisenberg’s 3D profile method to have high amyloid-like fibrillation potential through steric β-zipper formation. Peptide C6 containing the Cluster I consensus sequence was shown to oligomerize and form amyloid-like fibrils. Taking advantage of this, C6 was further applied to detect the S protein expression in vitro by fluorescence staining. Meanwhile, the coiled-coil-forming Leu/Ile heptad repeat sequences within the S protein were under-represented during peptide array scanning, in agreement with that long peptide lengths were required to attain high helix-mediated interaction avidity. The data suggest that short β-zipper-like self-binding peptides within the S protein could be identified through combining the peptide scanning and predictive methods, and could be exploited as biochemical detection reagents for viral infection.
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Affiliation(s)
- Si Min Zhang
- School of Biological Sciences, Nanyang Technological University, Singapore; Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Sweden
| | - Ying Liao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Tuan Ling Neo
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Yanning Lu
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Ding Xiang Liu
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Anders Vahlne
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Sweden
| | - James P Tam
- School of Biological Sciences, Nanyang Technological University, Singapore.
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Ng OW, Keng CT, Leung CSW, Peiris JSM, Poon LLM, Tan YJ. Substitution at aspartic acid 1128 in the SARS coronavirus spike glycoprotein mediates escape from a S2 domain-targeting neutralizing monoclonal antibody. PLoS One 2014; 9:e102415. [PMID: 25019613 PMCID: PMC4097068 DOI: 10.1371/journal.pone.0102415] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 06/19/2014] [Indexed: 12/28/2022] Open
Abstract
The Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) is the etiological agent for the infectious disease, SARS, which first emerged 10 years ago. SARS-CoV is a zoonotic virus that has crossed the species barriers to infect humans. Bats, which harbour a diverse pool of SARS-like CoVs (SL-CoVs), are believed to be the natural reservoir. The SARS-CoV surface Spike (S) protein is a major antigenic determinant in eliciting neutralizing antibody production during SARS-CoV infection. In our previous work, we showed that a panel of murine monoclonal antibodies (mAbs) that target the S2 subunit of the S protein are capable of neutralizing SARS-CoV infection in vitro (Lip KM et al, J Virol. 2006 Jan; 80(2): 941-50). In this study, we report our findings on the characterization of one of these mAbs, known as 1A9, which binds to the S protein at a novel epitope within the S2 subunit at amino acids 1111-1130. MAb 1A9 is a broadly neutralizing mAb that prevents viral entry mediated by the S proteins of human and civet SARS-CoVs as well as bat SL-CoVs. By generating mutant SARS-CoV that escapes the neutralization by mAb 1A9, the residue D1128 in S was found to be crucial for its interaction with mAb 1A9. S protein containing the substitution of D1128 with alanine (D1128A) exhibited a significant decrease in binding capability to mAb 1A9 compared to wild-type S protein. By using a pseudotyped viral entry assay, it was shown that the D1128A substitution in the escape virus allows it to overcome the viral entry blockage by mAb 1A9. In addition, the D1128A mutation was found to exert no effects on the S protein cell surface expression and incorporation into virion particles, suggesting that the escape virus retains the same viral entry property as the wild-type virus.
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Affiliation(s)
- Oi-Wing Ng
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System (NUHS), National University of Singapore, Singapore
| | - Choong-Tat Keng
- Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Singapore
| | - Cynthia Sau-Wai Leung
- Centre of Influenza Research, School of Public Health, The University of Hong Kong, Hong Kong, China
| | - J. S. Malik Peiris
- Centre of Influenza Research, School of Public Health, The University of Hong Kong, Hong Kong, China
| | - Leo Lit Man Poon
- Centre of Influenza Research, School of Public Health, The University of Hong Kong, Hong Kong, China
| | - Yee-Joo Tan
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System (NUHS), National University of Singapore, Singapore
- Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Singapore
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17
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Chen YN, Wu CC, Yeo Y, Xu P, Lin TL. A DNA prime-protein boost vaccination strategy targeting turkey coronavirus spike protein fragment containing neutralizing epitope against infectious challenge. Vet Immunol Immunopathol 2013; 152:359-69. [PMID: 23428360 PMCID: PMC7112546 DOI: 10.1016/j.vetimm.2013.01.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 01/10/2013] [Accepted: 01/12/2013] [Indexed: 11/15/2022]
Abstract
The present study was undertaken to determine immune response and protection efficacy of a spike (S) protein fragment containing neutralizing epitopes (4F/4R) of turkey coronavirus (TCoV) by priming with DNA vaccine and boosting with the recombinant protein from the corresponding DNA vaccine gene segment. Turkeys were vaccinated by priming with either one dose (G1-750DP) or two doses (G3-750DDP) of 750 μg DNA vaccine expressing 4F/4R S fragment and boosting with one dose of 200 μg 4F/4R S fragment. One dose of 100 μg DNA vaccine mixed with polyethyleneimine (PEI) and sodium hyaluronate (HA) followed by one dose of 750 μg DNA vaccine and one dose of 200 μg 4F/4R S fragment were given to the turkeys in group G2-100DPH. After infectious challenge by TCoV, clinical signs and TCoV detected by immunofluorescence antibody (IFA) assay were observed in less number of turkeys in vaccination groups than that in challenge control groups. TCoV viral RNA loads measured by quantitative real-time reverse transcription-PCR were lower in vaccinated turkeys than those in challenge control turkeys. The turkeys in G3-750DDP produced the highest level of TCoV S protein-specific antibody and virus neutralization (VN) titer. Comparing to the turkeys in G1-750DP, significantly less TCoV were detected by IFA in the turkeys in G2-100DPH receiving an extra dose of 100 μg DNA mixed with PEI and HA. The results indicated that DNA-prime protein-boost DNA vaccination regimen targeting TCoV S fragment encompassing neutralizing epitopes induced humoral immune response and partially protected turkeys against infectious challenge by TCoV.
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Affiliation(s)
- Yi-Ning Chen
- Department of Comparative Pathobiology, Purdue University 406 South University Street, West Lafayette, IN 47907, USA
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18
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Sunwoo HH, Palaniyappan A, Ganguly A, Bhatnagar PK, Das D, El-Kadi AOS, Suresh MR. Quantitative and sensitive detection of the SARS-CoV spike protein using bispecific monoclonal antibody-based enzyme-linked immunoassay. J Virol Methods 2012; 187:72-8. [PMID: 22995576 PMCID: PMC7112864 DOI: 10.1016/j.jviromet.2012.09.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 08/21/2012] [Accepted: 09/05/2012] [Indexed: 12/24/2022]
Abstract
The severe acute respiratory syndrome coronavirus (SARS-CoV) spike protein is known to mediate receptor interaction and immune recognition and thus it is considered as a major target for vaccine design. The spike protein plays an important role in virus entry, virus receptor interactions, and virus tropism. Sensitive diagnosis of SARS is essential for the control of the disease in humans. Recombinant SARS-CoV S1 antigen was produced and purified for the development of monoclonal and bi-specific monoclonal antibodies. The hybridomas secreting anti-S1 antibodies, F26G18 and P136.8D12, were fused respectively with the YP4 hybridoma to generate quadromas. The sandwich ELISA was formed by using F26G18 as a coating antibody and biotinylated F26G18 as a detection antibody with a detection limit of 0.037 μg/ml (p < 0.02). The same detection limit was found with P136.8D12 as a coating antibody and biotinylated F26G18 as a detection antibody. The sensitivity was improved (detection limit of 0.019 μg/ml), however, when using bi-specific monoclonal antibody (F157) as the detection antibody. In conclusion, the method described in this study allows sensitive detection of a recombinant SARS spike protein by sandwich ELISA with bi-specific monoclonal antibody and could be used for the diagnosis of patients suspected with SARS.
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Affiliation(s)
- Hoon H Sunwoo
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, 11361-87 Avenue, Edmonton, Alberta, Canada.
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19
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Chen YN, Wu CC, Lin TL. Identification and characterization of a neutralizing-epitope-containing spike protein fragment in turkey coronavirus. Arch Virol 2011; 156:1525-35. [PMID: 21594597 PMCID: PMC7086772 DOI: 10.1007/s00705-011-1020-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 05/02/2011] [Indexed: 12/27/2022]
Abstract
Little is known about the neutralizing epitopes in turkey coronavirus (TCoV). The spike (S) protein gene of TCoV was divided into 10 fragments to identify the antigenic region containing neutralizing epitopes. The expression and antigenicity of S fragments was confirmed by immunofluorescence antibody (IFA) assay using an anti-histidine monoclonal antibody or anti-TCoV serum. Polyclonal antibodies raised against expressed S1 (amino acid position 1 to 573 from start codon of S protein), 4F/4R (482-678), 6F/6R (830-1071), or Mod4F/Epi4R (476-520) S fragment recognized native S1 protein and TCoV in the intestines of TCoV-infected turkey embryos. Anti-TCoV serum reacted with recombinant 4F/4R, 6F/6R, and Mod4F/Epi4R in a western blot. The results of a virus neutralization assay indicated that the carboxyl terminal region of the S1 protein (Mod4F/Epi4R) or the combined carboxyl terminal S1 and amino terminal S2 protein (4F/4R) possesses the neutralizing epitopes, while the S2 fragment (6F/6R) contains antigenic epitopes but not neutralizing epitopes.
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Affiliation(s)
- Yi-Ning Chen
- Department of Comparative Pathobiology, Purdue University, 406 South University Street, West Lafayette, IN 47907, USA
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20
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Madu IG, Belouzard S, Whittaker GR. SARS-coronavirus spike S2 domain flanked by cysteine residues C822 and C833 is important for activation of membrane fusion. Virology 2009; 393:265-71. [PMID: 19717178 PMCID: PMC3594805 DOI: 10.1016/j.virol.2009.07.038] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 05/27/2009] [Accepted: 07/30/2009] [Indexed: 01/04/2023]
Abstract
The S2 domain of the coronavirus spike (S) protein is known to be responsible for mediating membrane fusion. In addition to a well-recognized cleavage site at the S1–S2 boundary, a second proteolytic cleavage site has been identified in the severe acute respiratory syndrome coronavirus (SARS-CoV) S2 domain (R797). C-terminal to this S2 cleavage site is a conserved region flanked by cysteine residues C822 and C833. Here, we investigated the importance of this well conserved region for SARS-CoV S-mediated fusion activation. We show that the residues between C822–C833 are well conserved across all coronaviruses. Mutagenic analysis of SARS-CoV S, combined with cell–cell fusion and pseudotyped virion infectivity assays, showed a critical role for the core-conserved residues C822, D830, L831, and C833. Based on available predictive models, we propose that the conserved domain flanked by cysteines 822 and 833 forms a loop structure that interacts with components of the SARS-CoV S trimer to control the activation of membrane fusion.
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Affiliation(s)
- Ikenna G Madu
- C4127 Veterinary Medical Center, Department of Microbiology and Immunology, Cornell University, Ithaca NY 14853, USA
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21
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Yan K, Tan W, Wang H, Wang Y, Zhang X, Li Y, Ruan L. SARS-CoV Spike Proteins Expressed by the Vaccinia Virus Tiantan Strain: Secreted SQ Protein Induces Robust Neutralization Antibody in Mice. Viral Immunol 2009; 22:57-66. [DOI: 10.1089/vim.2008.0064] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Affiliation(s)
- Kexia Yan
- National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Xuanwu District, Beijing, People's Republic of China
| | - Wenjie Tan
- National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Xuanwu District, Beijing, People's Republic of China
| | - Huijuan Wang
- National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Xuanwu District, Beijing, People's Republic of China
| | - Yue Wang
- National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Xuanwu District, Beijing, People's Republic of China
| | - Xiangmin Zhang
- National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Xuanwu District, Beijing, People's Republic of China
| | - Yan Li
- National Microbiology Laboratory, Canadian Science Centre for Human and Animal Health, Winnipeg, Manitoba, Canada
| | - Li Ruan
- National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Xuanwu District, Beijing, People's Republic of China
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Chu LHM, Chan SH, Tsai SN, Wang Y, Cheng CHK, Wong KB, Waye MMY, Ngai SM. Fusion core structure of the severe acute respiratory syndrome coronavirus (SARS-CoV): in search of potent SARS-CoV entry inhibitors. J Cell Biochem 2008; 104:2335-47. [PMID: 18442051 PMCID: PMC7166385 DOI: 10.1002/jcb.21790] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Severe acute respiratory coronavirus (SARS‐CoV) spike (S) glycoprotein fusion core consists of a six‐helix bundle with the three C‐terminal heptad repeat (HR2) helices packed against a central coiled‐coil of the other three N‐terminal heptad repeat (HR1) helices. Each of the three peripheral HR2 helices shows prominent contacts with the hydrophobic surface of the central HR1 coiled‐coil. The concerted protein–protein interactions among the HR helices are responsible for the fusion event that leads to the release of the SARS‐CoV nucleocapsid into the target host‐cell. In this investigation, we applied recombinant protein and synthetic peptide‐based biophysical assays to characterize the biological activities of the HR helices. In a parallel experiment, we employed a HIV‐luc/SARS pseudotyped virus entry inhibition assay to screen for potent inhibitory activities on HR peptides derived from the SARS‐CoV S protein HR regions and a series of other small‐molecule drugs. Three HR peptides and five small‐molecule drugs were identified as potential inhibitors. ADS‐J1, which has been used to interfere with the fusogenesis of HIV‐1 onto CD4+ cells, demonstrated the highest HIV‐luc/SARS pseudotyped virus‐entry inhibition activity among the other small‐molecule drugs. Molecular modeling analysis suggested that ADS‐J1 may bind to the deep pocket of the hydrophobic groove on the surface of the central coiled‐coil of SARS‐CoV S HR protein and prevent the entrance of the SARS‐CoV into the host cells. J. Cell. Biochem. 104: 2335–2347, 2008. © 2008 Wiley‐Liss, Inc.
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Affiliation(s)
- Ling-Hon Matthew Chu
- Molecular Biotechnology Program, The Chinese University of Hong Kong, Hong Kong, China
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23
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Wang S, Guo F, Liu K, Wang H, Rao S, Yang P, Jiang C. Endocytosis of the receptor-binding domain of SARS-CoV spike protein together with virus receptor ACE2. Virus Res 2008; 136:8-15. [PMID: 18554741 PMCID: PMC7114441 DOI: 10.1016/j.virusres.2008.03.004] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 03/03/2008] [Accepted: 03/07/2008] [Indexed: 01/10/2023]
Abstract
Cell entry of severe acute respiratory syndrome coronavirus (SARS-CoV) is mediated by the viral spike (S) protein. Amino acids 319-510 on the S protein have been mapped as the receptor-binding domain (RBD), which mediates binding to the SARS-CoV receptor angiotensin converting enzyme 2 (ACE2) on SARS-CoV susceptible cells. In this study, we expressed a fusion protein containing the human codon-optimized RBD of the SARS-CoV spike protein linked to the Fc portion of human IgG1 (named RBD-Fc) in HEK293 cells. The RBD-Fc protein was purified by affinity chromatography. The flow cytometry assay showed that the purified RBD-Fc protein could bind to ACE2. We demonstrated that the RBD spike protein alone could be internalized into SARS-CoV susceptible cells together with ACE2. We also showed that the removal of N-glycans from the RBD spike protein did not abolish this phenomenon. Our discoveries may have some implications for the development of the SARS vaccine.
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Affiliation(s)
- Shunxin Wang
- National Key Laboratory of Medical Molecular Biology, School of Basic Medicine, Peking Union Medical College, Tsinghua University and Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, Beijing 100005, China
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Suresh MR, Bhatnagar PK, Das D. Molecular targets for diagnostics and therapeutics of severe acute respiratory syndrome (SARS-CoV). JOURNAL OF PHARMACY AND PHARMACEUTICAL SCIENCES 2008; 11:1s-13s. [PMID: 19203466 DOI: 10.18433/j3j019] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PURPOSE The large number of deaths in a short period of time due to the spread of severe acute respiratory syndrome (SARS) infection led to the unparalleled collaborative efforts world wide to determine and characterize the new coronavirus (SARS-CoV). The full genome sequence was determined within weeks of the first outbreak by the Canadian group with international collaboration. As per the World Health Organization (WHO), the continual lack of a rapid laboratory test to aid the early diagnosis of suspected cases of SARS makes this area a priority for future research. To prevent deaths in the future, early diagnosis and therapy of this infectious disease is of paramount importance. METHODS This review describes the specific molecular targets for diagnostics and therapeutics of viral infection. RESULTS The three major diagnostic methods available for SARS includes viral RNA detection by reverse transcription polymerase chain reaction (RT-PCR), virus induced antibodies by immunofluorescence assay (IFA) or by enzyme linked immunosorbant assay (ELISA) of nucleocapsid protein (NP). The spike glycoprotein of SARS-CoV is the major inducer of neutralizing antibodies. The receptor binding domain (RBD) in the S1 region of the spike glycoprotein contains multiple conformational epitopes that induces highly potent neutralizing antibodies. The genetically engineered attenuated form of the virus or viral vector vaccine encoding for the SARS-CoV spike glycoprotein has been shown to elicit protective immunity in vaccinated animals. CONCLUSION NP is the preferred target for routine detection of SARS-CoV infection by ELISA which is an economical method compared to other methods. The RBD of the spike glycoprotein is both a functional domain for cell receptor binding and also a major neutralizing determinant of SARS-CoV. The progress in evaluating a therapeutic or vaccine would depend on the avail ability of clinically relevant animal model.
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Affiliation(s)
- Mavanur R Suresh
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada.
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Han DP, Lohani M, Cho MW. Specific asparagine-linked glycosylation sites are critical for DC-SIGN- and L-SIGN-mediated severe acute respiratory syndrome coronavirus entry. J Virol 2007; 81:12029-39. [PMID: 17715238 PMCID: PMC2168787 DOI: 10.1128/jvi.00315-07] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Severe acute respiratory syndrome (SARS) is caused by a newly emerged coronavirus (CoV) designated SARS-CoV. The virus utilizes angiotensin-converting enzyme 2 (ACE2) as the primary receptor. Although the idea is less clear and somewhat controversial, SARS-CoV is thought to use C-type lectins DC-SIGN and/or L-SIGN (collectively referred to as DC/L-SIGN) as alternative receptors or as enhancer factors that facilitate ACE2-mediated virus infection. In this study, the function of DC/L-SIGN in SARS-CoV infection was examined in detail. The results of our study clearly demonstrate that both proteins serve as receptors independently of ACE2 and that there is a minimal level of synergy between DC/L-SIGN and ACE2. As expected, glycans on spike (S) glycoprotein are important for DC/L-SIGN-mediated virus infection. Site-directed mutagenesis analyses have identified seven glycosylation sites on the S protein critical for DC/L-SIGN-mediated virus entry. They include asparagine residues at amino acid positions 109, 118, 119, 158, 227, 589, and 699, which are distinct from residues of the ACE2-binding domain (amino acids 318 to 510). Amino acid sequence analyses of S proteins encoded by viruses isolated from animals and humans suggest that glycosylation sites N227 and N699 have facilitated zoonotic transmission.
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Affiliation(s)
- Dong P Han
- Case Western Reserve University School of Medicine, Department of Medicine, Division of Infectious Diseases, 10900 Euclid Avenue, Cleveland, OH 44106-4984, USA
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Liu C, Li X, Zhang C, Xu S, Shao Y, Zhuang H, Che X, Qiu Y, Yin H, Li D, Wang Y. Establishment of a reference panel for the detection of anti-SARS-CoV antibodies. Biologicals 2007; 35:203-10. [PMID: 17261372 PMCID: PMC7129324 DOI: 10.1016/j.biologicals.2006.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Revised: 09/17/2006] [Accepted: 11/07/2006] [Indexed: 10/25/2022] Open
Abstract
The immunological assays for detection of antibodies against SARS-CoV were developed in-house and some of them are available commercially. However, the antigens used in these assays differed. In order to validate the reliability of these assays, the standard panel should be established. In this study, we have expressed and purified severe acute respiratory syndrome (SARS) structural proteins and their fragments and developed indirect enzyme-linked immunosorbent assays (ELISAs) that detect antibodies against the SARS N, N(1), N(2), S(1), S(C), S(2), and M proteins as well as the human coronavirus OC43 and 229E N proteins. These assays were used to screen 58 samples from SARS convalescent patients, 40 serial serum specimens from patients at different phases of SARS infection, and 88 plasma specimens from normal blood donors. The samples from normal blood donors were also tested for antibodies against other respiratory virus. The representative samples were chosen to comprise a reference panel of SARS antibodies that may be used for the detection of SARS. The panel is composed of 25 positive samples, 25 negative samples, 7 diluted samples for anti-N antibody, 6 diluted samples for anti-S antibody, and one sample for validating precision. Comparison of detection results with different SARS antibody assays indicated that our panel should differentiate the specificity and sensitivity of different assays.
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Affiliation(s)
- Chunyu Liu
- Department of Cell Biology, National Institute for the Control of Pharmaceutical and Biological Products, No. 2 Tiantanxili, Chongwen District, Beijing 100050, PR China
| | - Xiuhua Li
- Department of Cell Biology, National Institute for the Control of Pharmaceutical and Biological Products, No. 2 Tiantanxili, Chongwen District, Beijing 100050, PR China
| | - Chuntao Zhang
- Department of Cell Biology, National Institute for the Control of Pharmaceutical and Biological Products, No. 2 Tiantanxili, Chongwen District, Beijing 100050, PR China
| | - Sihong Xu
- Department of Cell Biology, National Institute for the Control of Pharmaceutical and Biological Products, No. 2 Tiantanxili, Chongwen District, Beijing 100050, PR China
| | - Yiming Shao
- Center for Disease Control, Beijing 100052, China
| | - Hui Zhuang
- Center of Medical Division, Peking University, Beijing, China
| | - Xiaoyan Che
- Zhujiang Hospital, Guangzhou Province, China
| | - Yan Qiu
- Beijing Blood Center, Beijing, China
| | - Hongzhang Yin
- Department of Cell Biology, National Institute for the Control of Pharmaceutical and Biological Products, No. 2 Tiantanxili, Chongwen District, Beijing 100050, PR China
| | - Defu Li
- Department of Cell Biology, National Institute for the Control of Pharmaceutical and Biological Products, No. 2 Tiantanxili, Chongwen District, Beijing 100050, PR China
| | - Youchun Wang
- Department of Cell Biology, National Institute for the Control of Pharmaceutical and Biological Products, No. 2 Tiantanxili, Chongwen District, Beijing 100050, PR China
- Corresponding author. Tel.: +86 10 6709 5415; fax: +86 10 6511 3538.
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Kuate S, Cinatl J, Doerr HW, Uberla K. Exosomal vaccines containing the S protein of the SARS coronavirus induce high levels of neutralizing antibodies. Virology 2007; 362:26-37. [PMID: 17258782 PMCID: PMC7103344 DOI: 10.1016/j.virol.2006.12.011] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Revised: 10/05/2006] [Accepted: 12/08/2006] [Indexed: 12/25/2022]
Abstract
Infection with the SARS-associated coronavirus (SARS-CoV) induces an atypical pulmonary disease with a high lethality rate. Although the initial SARS epidemic was contained, sporadic outbreaks of the disease still occur, suggesting a continuous need for a vaccine against this virus. We therefore explored exosome-based vaccines containing the spike S proteins of SARS-CoV. S-containing exosomes were obtained by replacing the transmembrane and cytoplasmic domains of the S protein by those of VSV-G. The immunogenicity and efficacy of the S-containing exosomes were tested in mice and compared to an adenoviral vector vaccine expressing the S protein. Both, S-containing exosomes and the adenoviral vector vaccine induced neutralizing antibody titers. After priming with the SARS-S exosomal vaccine and boosting with the adenoviral vector the neutralizing antibody titers exceeded those observed in the convalescent serum of a SARS patient. Both approaches were effective in a SARS-S-expressing tumor challenge model and thus warrant further investigation.
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Affiliation(s)
- Seraphin Kuate
- Department of Molecular and Medical Virology, Ruhr-University Bochum, D-44780 Bochum, Germany.
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Kuhn JH, Li W, Radoshitzky SR, Choe H, Farzan M. Severe Acute Respiratory Syndrome Coronavirus Entry as a Target of Antiviral Therapies. Antivir Ther 2007. [DOI: 10.1177/135965350701200s05.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The identification in 2003 of a coronavirus as the aetiological agent of severe acute respiratory syndrome (SARS) intensified efforts to understand the biology of corona-viruses in general and SARS coronavirus (SARS-CoV) in particular. Rapid progress was made in describing the SARS-CoV genome, evolution and lifecycle. Identification of angiotensin-converting enzyme 2 (ACE2) as an obligate cellular receptor for SARS-CoV contributed to understanding of the SARS-CoV entry process, and helped to characterize two targets of antiviral therapeutics: the SARS-CoV spike protein and ACE2. Here we describe the role of these proteins in SARS-CoV replication and potential therapeutic strategies aimed at preventing entry of SARS-CoV into target cells.
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Affiliation(s)
- Jens H Kuhn
- Department of Microbiology and Molecular Genetics, Harvard Medical School, New England Primate Research Center, Southborough, MA, USA
- Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Wenhui Li
- Department of Microbiology and Molecular Genetics, Harvard Medical School, New England Primate Research Center, Southborough, MA, USA
| | - Sheli R Radoshitzky
- Department of Microbiology and Molecular Genetics, Harvard Medical School, New England Primate Research Center, Southborough, MA, USA
| | - Hyeryun Choe
- Department of Pediatrics, Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Michael Farzan
- Department of Microbiology and Molecular Genetics, Harvard Medical School, New England Primate Research Center, Southborough, MA, USA
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Shih YP, Chen CY, Liu SJ, Chen KH, Lee YM, Chao YC, Chen YMA. Identifying epitopes responsible for neutralizing antibody and DC-SIGN binding on the spike glycoprotein of the severe acute respiratory syndrome coronavirus. J Virol 2006; 80:10315-24. [PMID: 17041212 PMCID: PMC1641789 DOI: 10.1128/jvi.01138-06] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The severe acute respiratory syndrome-associated coronavirus (SARS-CoV) uses dendritic cell-specific ICAM-3 grabbing nonintegrin (DC-SIGN) to facilitate cell entry via cellular receptor-angiotensin-converting enzyme 2. For this project, we used recombinant baculoviruses expressing different lengths of SARS-CoV spike (S) protein in a capture assay to deduce the minimal DC-SIGN binding region. Our results identified the region location between amino acid (aa) residues 324 to 386 of the S protein. We then generated nine monoclonal antibodies (MAbs) against the S protein to map the DC-SIGN-binding domain using capture assays with pseudotyped viruses and observed that MAb SIa5 significantly blocked S protein-DC-SIGN interaction. An enhancement assay using the HKU39849 SARS-CoV strain and human immature dendritic cells confirmed our observation. Data from a pepscan analysis and M13 phage peptide display library system mapped the reactive MAb SIa5 epitope to aa residues 363 to 368 of the S protein. Results from a capture assay testing three pseudotyped viruses with mutated N-linked glycosylation sites of the S protein indicate that only two pseudotyped viruses (N330Q and N357Q, both of which lost glycosylation sites near the SIa5 epitope) had diminished DC-SIGN-binding capacity. We also noted that MAb SIb4 exerted a neutralizing effect against HKU39849; its reactive epitope was mapped to aa residues 435 to 439 of the S protein. We offer the data to facilitate the development of therapeutic agents and preventive vaccines against SARS-CoV infection.
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MESH Headings
- Antibodies, Monoclonal
- Antibodies, Viral
- Antigens, Viral/genetics
- Baculoviridae/genetics
- Base Sequence
- Binding Sites/genetics
- Cell Adhesion Molecules/metabolism
- DNA, Viral/genetics
- Dendritic Cells/immunology
- Dendritic Cells/virology
- Epitope Mapping
- Epitopes/chemistry
- Epitopes/genetics
- Glycosylation
- Humans
- In Vitro Techniques
- Lectins, C-Type/metabolism
- Membrane Glycoproteins/chemistry
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/immunology
- Models, Molecular
- Mutagenesis, Site-Directed
- Neutralization Tests
- Protein Binding
- Protein Structure, Tertiary
- Receptors, Cell Surface/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- Severe acute respiratory syndrome-related coronavirus/genetics
- Severe acute respiratory syndrome-related coronavirus/immunology
- Severe Acute Respiratory Syndrome/immunology
- Severe Acute Respiratory Syndrome/virology
- Spike Glycoprotein, Coronavirus
- Viral Envelope Proteins/chemistry
- Viral Envelope Proteins/genetics
- Viral Envelope Proteins/immunology
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Affiliation(s)
- Yi-Ping Shih
- AIDS Prevention and Research Center, National Yang-Ming University, Taipei 111, Taiwan, Republic of China
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Zhao J, Wang W, Yuan Z, Jia R, Zhao Z, Xu X, Lv P, Zhang Y, Jiang C, Gao XM. A study on antigenicity and receptor-binding ability of fragment 450-650 of the spike protein of SARS coronavirus. Virology 2006; 359:362-70. [PMID: 17055551 PMCID: PMC7103343 DOI: 10.1016/j.virol.2006.09.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Revised: 07/11/2006] [Accepted: 09/18/2006] [Indexed: 11/01/2022]
Abstract
The spike (S) protein of SARS coronavirus (SARS-CoV) is responsible for viral binding with ACE2 molecules. Its receptor-binding motif (S-RBM) is located between residues 424 and 494, which folds into 2 anti-parallel beta-sheets, beta5 and beta6. We have previously demonstrated that fragment 450-650 of the S protein (S450-650) is predominantly recognized by convalescent sera of SARS patients. The N-terminal 60 residues (450-510) of the S450-650 fragment covers the entire beta6 strand of S-RBM. In the present study, we demonstrate that patient sera predominantly recognized 2 linear epitopes outside the beta6 fragment, while the mouse antisera, induced by immunization of BALB/c mice with recombinant S450-650, mainly recognized the beta6 strand-containing region. Unlike patient sera, however, the mouse antisera were unable to inhibit the infectivity of S protein-expressing (SARS-CoV-S) pseudovirus. Fusion protein between green fluorescence protein (GFP) and S450-650 (S450-650-GFP) was able to stain Vero E6 cells and deletion of the beta6 fragment rendered the fusion product (S511-650-GFP) unable to do so. Similarly, recombinant S450-650, but not S511-650, was able to block the infection of Vero E6 cells by the SARS-CoV-S pseudovirus. Co-precipitation experiments confirmed that S450-650 was able to specifically bind with ACE2 molecules in lysate of Vero E6 cells. However, the ability of S450-510, either alone or in fusion with GFP, to bind with ACE2 was significantly poorer compared with S450-650. Our data suggest a possibility that, although the beta6 strand alone is able to bind with ACE2 with relatively high affinity, residues outside the S-RBM could also assist the receptor binding of SARS-CoV-S protein.
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Affiliation(s)
- Jincun Zhao
- Department of Immunology, Peking University Health Science Center, Peking University, 38 Xueyuan Road, Beijing 100083, China
| | - Wei Wang
- Department of Immunology, Peking University Health Science Center, Peking University, 38 Xueyuan Road, Beijing 100083, China
| | - Zhihong Yuan
- Department of Immunology, Peking University Health Science Center, Peking University, 38 Xueyuan Road, Beijing 100083, China
| | - Rujing Jia
- Department of Immunology, Peking University Health Science Center, Peking University, 38 Xueyuan Road, Beijing 100083, China
| | - Zhendong Zhao
- Department of Immunology, Peking University Health Science Center, Peking University, 38 Xueyuan Road, Beijing 100083, China
| | - Xiaojun Xu
- Department of Immunology, Peking University Health Science Center, Peking University, 38 Xueyuan Road, Beijing 100083, China
| | - Ping Lv
- Department of Immunology, Peking University Health Science Center, Peking University, 38 Xueyuan Road, Beijing 100083, China
| | - Yan Zhang
- Department of Immunology, Peking University Health Science Center, Peking University, 38 Xueyuan Road, Beijing 100083, China
| | - Chengyu Jiang
- Institute of Basic Medical Sciences, Peking Union Medical College, Beijing, China
| | - Xiao-Ming Gao
- Department of Immunology, Peking University Health Science Center, Peking University, 38 Xueyuan Road, Beijing 100083, China
- Corresponding author. Fax: +86 10 82801156.
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Zhang CY, Wei JF, He SH. Adaptive evolution of the spike gene of SARS coronavirus: changes in positively selected sites in different epidemic groups. BMC Microbiol 2006; 6:88. [PMID: 17020602 PMCID: PMC1609170 DOI: 10.1186/1471-2180-6-88] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2006] [Accepted: 10/04/2006] [Indexed: 12/28/2022] Open
Abstract
Background It is believed that animal-to-human transmission of severe acute respiratory syndrome (SARS) coronavirus (CoV) is the cause of the SARS outbreak worldwide. The spike (S) protein is one of the best characterized proteins of SARS-CoV, which plays a key role in SARS-CoV overcoming species barrier and accomplishing interspecies transmission from animals to humans, suggesting that it may be the major target of selective pressure. However, the process of adaptive evolution of S protein and the exact positively selected sites associated with this process remain unknown. Results By investigating the adaptive evolution of S protein, we identified twelve amino acid sites (75, 239, 244, 311, 479, 609, 613, 743, 765, 778, 1148, and 1163) in the S protein under positive selective pressure. Based on phylogenetic tree and epidemiological investigation, SARS outbreak was divided into three epidemic groups: 02–04 interspecies, 03-early-mid, and 03-late epidemic groups in the present study. Positive selection was detected in the first two groups, which represent the course of SARS-CoV interspecies transmission and of viral adaptation to human host, respectively. In contrast, purifying selection was detected in 03-late group. These indicate that S protein experiences variable positive selective pressures before reaching stabilization. A total of 25 sites in 02–04 interspecies epidemic group and 16 sites in 03-early-mid epidemic group were identified under positive selection. The identified sites were different between these two groups except for site 239, which suggests that positively selected sites are changeable between groups. Moreover, it was showed that a larger proportion (24%) of positively selected sites was located in receptor-binding domain (RBD) than in heptad repeat (HR)1-HR2 region in 02–04 interspecies epidemic group (p = 0.0208), and a greater percentage (25%) of these sites occurred in HR1–HR2 region than in RBD in 03-early-mid epidemic group (p = 0.0721). These suggest that functionally different domains of S protein may not experience same positive selection in each epidemic group. In addition, three specific replacements (F360S, T487S and L665S) were only found between 03-human SARS-CoVs and strains from 02–04 interspecies epidemic group, which reveals that selective sweep may also force the evolution of S genes before the jump of SARS-CoVs into human hosts. Since certain residues at these positively selected sites are associated with receptor recognition and/or membrane fusion, they are likely to be the crucial residues for animal-to-human transmission of SARS-CoVs, and subsequent adaptation to human hosts. Conclusion The variation of positive selective pressures and positively selected sites are likely to contribute to the adaptive evolution of S protein from animals to humans.
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Affiliation(s)
- Chi-Yu Zhang
- Department of Biochemistry and Molecular Biology, Jiangsu University School of Medical Technology, Zhenjiang, Jiangsu 212001, China
| | - Ji-Fu Wei
- The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210026, China
| | - Shao-Heng He
- The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210026, China
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Yeung KS, Yamanaka GA, Meanwell NA. Severe acute respiratory syndrome coronavirus entry into host cells: Opportunities for therapeutic intervention. Med Res Rev 2006; 26:414-33. [PMID: 16521129 PMCID: PMC7168515 DOI: 10.1002/med.20055] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A novel human coronavirus (CoV) has been identified as the etiological agent that caused the severe acute respiratory syndrome (SARS) outbreak in 2003. The spike (S) protein of this virus is a type I surface glycoprotein that mediates binding of the virus to the host receptor and the subsequent fusion between the viral and host membranes. Because of its critical role in viral entry, the S protein is an important target for the development of anti-SARS CoV therapeutics and prophylactics. This article reviews the structure and function of the SARS CoV S protein in the context of its role in virus entry. Topics that are discussed include: the interaction between the S1 domain of the SARS spike protein and the cellular receptor, angiotensin converting enzyme 2 (ACE2), and the structural features of the ectodomain of ACE2; the antigenic determinants presented by the S protein and the nature of neutralizing monoclonal antibodies that are elicited in vivo; the structure of the 4,3-hydrophobic heptad repeats HR1 and HR2 of the S2 domain and their interaction to form a six-helical bundle during the final stages of fusion. Opportunities for the design and development of anti-SARS agents based on the inhibition of receptor binding, the therapeutic uses of S-directed monoclonal antibodies and inhibitors of HR1-HR2 complex formation are presented.
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Affiliation(s)
- Kap-Sun Yeung
- Department of Chemistry, The Bristol-Myers Squibb Pharmaceutical Research Institute, 5 Research Parkway, P.O. Box 5100, Wallingford, Connecticut 06492, USA.
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Lee JS, Poo H, Han DP, Hong SP, Kim K, Cho MW, Kim E, Sung MH, Kim CJ. Mucosal immunization with surface-displayed severe acute respiratory syndrome coronavirus spike protein on Lactobacillus casei induces neutralizing antibodies in mice. J Virol 2006; 80:4079-87. [PMID: 16571824 PMCID: PMC1440448 DOI: 10.1128/jvi.80.8.4079-4087.2006] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Induction of mucosal immunity may be important for preventing SARS-CoV infections. For safe and effective delivery of viral antigens to the mucosal immune system, we have developed a novel surface antigen display system for lactic acid bacteria using the poly-gamma-glutamic acid synthetase A protein (PgsA) of Bacillus subtilis as an anchoring matrix. Recombinant fusion proteins comprised of PgsA and the Spike (S) protein segments SA (residues 2 to 114) and SB (residues 264 to 596) were stably expressed in Lactobacillus casei. Surface localization of the fusion protein was verified by cellular fractionation analyses, immunofluorescence microscopy, and flow cytometry. Oral and nasal inoculations of recombinant L. casei into mice resulted in high levels of serum immunoglobulin G (IgG) and mucosal IgA, as demonstrated by enzyme-linked immunosorbent assays using S protein peptides. More importantly, these antibodies exhibited potent neutralizing activities against severe acute respiratory syndrome (SARS) pseudoviruses. Orally immunized mice mounted a greater neutralizing-antibody response than those immunized intranasally. Three new neutralizing epitopes were identified on the S protein using a peptide neutralization interference assay (residues 291 to 308, 520 to 529, and 564 to 581). These results indicate that mucosal immunization with recombinant L. casei expressing SARS-associated coronavirus S protein on its surface provides an effective means for eliciting protective immune response against the virus.
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He Y, Li J, Jiang S. A single amino acid substitution (R441A) in the receptor-binding domain of SARS coronavirus spike protein disrupts the antigenic structure and binding activity. Biochem Biophys Res Commun 2006; 344:106-13. [PMID: 16615996 PMCID: PMC7092835 DOI: 10.1016/j.bbrc.2006.03.139] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Accepted: 03/21/2006] [Indexed: 01/08/2023]
Abstract
The spike (S) protein of severe acute respiratory syndrome coronavirus (SARS-CoV) has two major functions: interacting with the receptor to mediate virus entry and inducing protective immunity. Coincidently, the receptor-binding domain (RBD, residues 318-510) of SAR-CoV S protein is a major antigenic site to induce neutralizing antibodies. Here, we used RBD-Fc, a fusion protein containing the RBD and human IgG1 Fc, as a model in the studies and found that a single amino acid substitution in the RBD (R441A) could abolish the immunogenicity of RBD to induce neutralizing antibodies in immunized mice and rabbits. With a panel of anti-RBD mAbs as probes, we observed that R441A substitution was able to disrupt the majority of neutralizing epitopes in the RBD, suggesting that this residue is critical for the antigenic structure responsible for inducing protective immune responses. We also demonstrated that the RBD-Fc bearing R441A mutation could not bind to soluble and cell-associated angiotensin-converting enzyme 2 (ACE2), the functional receptor for SARS-CoV and failed to block S protein-mediated pseudovirus entry, indicating that this point mutation also disrupted the receptor-binding motif (RBM) in the RBD. Taken together, these data provide direct evidence to show that a single amino acid residue at key position in the RBD can determine the major function of SARS-CoV S protein and imply for designing SARS vaccines and therapeutics.
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Affiliation(s)
- Yuxian He
- Lindsley F. Kimball Research Institute, The New York Blood Center, New York, NY 10021, USA.
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35
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Tarnovitski N, Matthews LJ, Sui J, Gershoni JM, Marasco WA. Mapping a neutralizing epitope on the SARS coronavirus spike protein: computational prediction based on affinity-selected peptides. J Mol Biol 2006; 359:190-201. [PMID: 16630634 PMCID: PMC7094247 DOI: 10.1016/j.jmb.2006.03.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Revised: 02/28/2006] [Accepted: 03/02/2006] [Indexed: 11/16/2022]
Abstract
Rapid elucidation of neutralizing antibody epitopes on emerging viral pathogens like severe acute respiratory syndrome (SARS) coronavirus (CoV) or highly pathogenic avian influenza H5N1 virus is of great importance for rational design of vaccines against these viruses. Here we combined screening of phage display random peptide libraries with a unique computer algorithm “Mapitope” to identify the discontinuous epitope of 80R, a potent neutralizing human anti-SARS monoclonal antibody against the spike protein. Using two different types of random peptide libraries which display cysteine-constrained loops or linear 13–15-mer peptides, independent panels containing 42 and 18 peptides were isolated, respectively. These peptides, which had no apparent homologous motif within or between the peptide pools and spike protein, were deconvoluted into amino acid pairs (AAPs) by Mapitope and the statistically significant pairs (SSPs) were defined. Mapitope analysis of the peptides was first performed on a theoretical model of the spike and later on the genuine crystal structure. Three clusters (A, B and C) were predicted on both structures with remarkable overlap. Cluster A ranked the highest in the algorithm in both models and coincided well with the sites of spike protein that are in contact with the receptor, consistent with the observation that 80R functions as a potent entry inhibitor. This study demonstrates that by using this novel strategy one can rapidly predict and identify a neutralizing antibody epitope, even in the absence of the crystal structure of its target protein.
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Affiliation(s)
- Natalia Tarnovitski
- Department of Cell Research and Immunology, Tel Aviv University, George S. Wise Faculty of Life Science, Tel Aviv 69978, Israel
| | - Leslie J. Matthews
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston MA, USA
| | - Jianhua Sui
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston MA, USA
- Department of Medicine, Harvard Medical School, Boston MA, USA
| | - Jonathan M. Gershoni
- Department of Cell Research and Immunology, Tel Aviv University, George S. Wise Faculty of Life Science, Tel Aviv 69978, Israel
- Corresponding author.
| | - Wayne A. Marasco
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston MA, USA
- Department of Medicine, Harvard Medical School, Boston MA, USA
- Corresponding author.
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Tsunetsugu‐Yokota Y, Ohnishi K, Takemori T. Severe acute respiratory syndrome (SARS) coronavirus: application of monoclonal antibodies and development of an effective vaccine. Rev Med Virol 2006; 16:117-31. [PMID: 16518829 PMCID: PMC7169118 DOI: 10.1002/rmv.492] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2005] [Revised: 12/13/2005] [Accepted: 12/13/2005] [Indexed: 12/28/2022]
Abstract
SARS-CoV is a new type of human coronavirus identified as a causative agent of severe acute respiratory syndrome (SARS). On the occasion of the SARS outbreak, various monoclonal antibodies (mAbs) against SARS-CoV have been developed and applied for diagnosis, clinical management and basic research. In this review, we overview the biochemical and functional properties and applications of these SARS-CoV mAbs. We also focus on a variety of vaccines currently under development and discuss the immune response elicited by these vaccines in animal models, hopefully to better understand what we need to do next to fight against newly emerging pathogens in the future.
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Affiliation(s)
- Yasuko Tsunetsugu‐Yokota
- Department of Immunology, National Institute of Infectious Diseases, Toyama‐cho, Shinjuku‐ku, Tokyo, Japan
| | - Kazuo Ohnishi
- Department of Immunology, National Institute of Infectious Diseases, Toyama‐cho, Shinjuku‐ku, Tokyo, Japan
| | - Toshitada Takemori
- Department of Immunology, National Institute of Infectious Diseases, Toyama‐cho, Shinjuku‐ku, Tokyo, Japan
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Chen J, Miao L, Li JM, Li YY, Zhu QY, Zhou CL, Fang HQ, Chen HP. Receptor-binding domain of SARS-Cov spike protein: Soluble expression in E.coli, purification and functional characterization. World J Gastroenterol 2005; 11:6159-64. [PMID: 16273643 PMCID: PMC4436633 DOI: 10.3748/wjg.v11.i39.6159] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To find a soluble and functional recombinant receptor-binding domain of severe acute respiratory syndrome-associated coronavirus (SARS-Cov), and to analyze its receptor binding ability.
METHODS: Three fusion tags (glutathione S-transferase, GST; thioredoxin, Trx; maltose-binding protein, MBP), which preferably contributes to increasing solubility and to facilitating the proper folding of heteroprotein, were used to acquire the soluble and functional expression of RBD protein in Escherichia coli (BL21(DE3) and Rosetta-gamiB(DE3) strains). The receptor binding ability of the purified soluble RBD protein was then detected by ELISA and flow cytometry assay.
RESULTS: RBD of SARS-Cov spike protein was expressed as inclusion body when fused as TrxA tag form in both BL21 (DE3) and Rosetta-gamiB (DE3) under many different cultures and induction conditions. And there was no visible expression band on SDS-PAGE when RBD was expressed as MBP tagged form. Only GST tagged RBD was soluble expressed in BL21(DE3), and the protein was purified by ÄKTA Prime Chromatography system. The ELISA data showed that GST.RBD antigen had positive reaction with anti-RBD mouse monoclonal antibody 1A5. Further flow cytometry assay demonstrated the high efficiency of RBD's binding ability to ACE2 (angiotensin-converting enzyme 2) positive Vero E6 cell. And ACE2 was proved as a cellular receptor that meditated an initial-affinity interaction with SARS-Cov spike protein. The geometrical mean of GST and GST.RBD binding to Vero E6 cells were 77.08 and 352.73 respectively.
CONCLUSION: In this paper, we get sufficient soluble N terminal GST tagged RBD protein expressed in E.coli BL21(DE3); data from ELISA and flow cytometry assay demo-nstrate that the recombinant protein is functional and binding to ACE2 positive Vero E6 cell efficiently. And the recombinant RBD derived from E.coli can be used to developing subunit vaccine to block S protein binding with receptor and to neutralizing SARS-Cov infection.
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Affiliation(s)
- Jing Chen
- Institute of Biotechnology, Academy of Military Medical Science, 20 Dongda Street, Fengtai District, Beijing 100071, China
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Abstract
Severe acute respiratory syndrome (SARS) is an emerging infectious disease caused by a new coronavirus (SARS-CoV). Recent studies suggest that SARS-CoV is zoonotic and may have a broad host range besides humans. Although the global outbreak of SARS has been contained, there are serious concerns over its re-emergence and bioterrorism potential. As a part of preparedness, development of a safe and effective vaccine is one of the highest priorities in fighting SARS. A number of candidate vaccines, using a variety of approaches, are under development. The first vaccine tested in clinical trial is made from the inactivated form of SARS-CoV. Several live attenuated, genetically engineered or vector vaccines encoding the SARS-CoV spike (S) protein have been in pre-clinical studies. These vaccine candidates are effective in terms of eliciting protective immunity in the vaccinated animals. However, caution should be taken with the safety of whole virus or full-length S protein-based immunogens in humans because they may induce harmful immune or inflammatory responses. We propose to use the receptor-binding domain (RBD) of SARS-CoV S protein (residues 318--510) for developing a safe and effective subunit SARS vaccine, as it is not only a functional domain that mediates virus-receptor binding but also a major neutralization determinant of SARSCoV. It has been demonstrated that the RBD of SARS-CoV S protein contains multiple conformational epitopes capable of inducing highly potent neutralizing antibody responses and protective immunity.
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Affiliation(s)
- Yuxian He
- Viral Immunology Laboratory, Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York 10021, USA
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Guo Y, Sun S, Wang K, Zhang S, Zhu W, Chen Z. Elicitation of immunity in mice after immunization with the S2 subunit of the severe acute respiratory syndrome coronavirus. DNA Cell Biol 2005; 24:510-5. [PMID: 16101349 DOI: 10.1089/dna.2005.24.510] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The S2 domain of the severe acute respiratory syndrome coronavirus (SARS-CoV) spike (S) protein is responsible for fusion between virus and target cell membranes, and is expected to be immungenic. In this study, we investigated the immune responses against the S2 subunit in BALB/c mice, which were vaccinated either with plasmid DNA encoding the S2 domain (residues 681-1120), the recombinant S2 fragment (residues 681-980) in incomplete Freund's adjuvant, or with inactivated SARS-CoV. The increased number of specific cytotoxic cells (CTLs) and the high titer of specific antibody showed stimulation of both arms of the immune system in these groups. The shift in cytokines suggested that Th1-polarized immune response was induced by plasmid pCoVS2, meanwhile the Th2-dominant response was induced by recombinant S2 fragment and inactivated vaccine. However, the titer of neutralizing antibodies was only detectable in mice immunized with inactivated virus, but not with pCoVS2 plasmid. Taken together, the S2 domain could induce specific cellular immune response and a high level of total IgG but little neutralizing antibodies against infection by SARSCoV.
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Affiliation(s)
- Yingjun Guo
- Department of Medical Genetics, The Second Military Medical University, Shanghai, People's Republic of China
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40
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Chang CY, Hong WWL, Chong P, Wu SC. Influence of intron and exon splicing enhancers on mammalian cell expression of a truncated spike protein of SARS-CoV and its implication for subunit vaccine development. Vaccine 2005; 24:1132-41. [PMID: 16194584 PMCID: PMC7115599 DOI: 10.1016/j.vaccine.2005.09.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2005] [Revised: 09/03/2005] [Accepted: 09/05/2005] [Indexed: 12/04/2022]
Abstract
The spike (S) protein of severe acute respiratory syndrome coronavirus (SARS-CoV) is important for vaccine development. A truncated S protein of the TW1 strain, STR2 (88 kDa), carrying three S fragments (S74–253, S294–739, and S1129–1255) was investigated to study the influences of intron and exon splicing enhancers to improve STR2 protein expression in mammalian cells. Our results showed that STR2 protein expression with the use of an 138 base-pair intron addition increased by 1.9-, 2.5-, and 4.1-fold in Vero E6, QBI-293A cells, and CHO/dhFr− cells (dihydrofolate reductase [dhfr] gene deficient CHO cells), respectively. Using the exon splicing enhancers, including a bidirectional splicing enhancer (BSE) or an exon splicing enhancer derived from the EDA alternative exon of the fibronectin gene (EDA ESE), were also found to increase STR2 protein expression in CHO/dhFr− cells by 1.7- and 2.6-fold. Nevertheless, combination of the intron and the exon splicing enhancers resulted in suppressing the intron-enhancing e STR2 protein expression in in CHO/dhFr− cells. Our studies also demonstrated the STR2 protein was mainly as the Endo H-sensitive glycoprotein (115 kDa) expressed in Vero E6, QBI-293A, and CHO/dhFr− cells. However, only a minor form of the Endo H-resistant glycoproteins (∼130 kDa) was detected in CHO/dhFr− cells. Taken together, our results indicated that intron had a better enhancing effect on STR2 protein expression than exon splicing enhancers, and the expression of ∼130 kDa STR2 glycoprotein was enhanced by the intron addition into the expression vector construct. Results of the present study can provide an optimal strategy to enhance SARS-CoV S protein expression in mammalian cells and may contribute to the development of SARS-CoV subunit vaccine.
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Affiliation(s)
- Chia-Yin Chang
- Institute of Biotechnology, Department of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan
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41
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Zhang Y, Zheng N, Hao P, Cao Y, Zhong Y. A molecular docking model of SARS-CoV S1 protein in complex with its receptor, human ACE2. Comput Biol Chem 2005; 29:254-7. [PMID: 15979045 PMCID: PMC7106554 DOI: 10.1016/j.compbiolchem.2005.04.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2005] [Revised: 04/17/2005] [Accepted: 04/18/2005] [Indexed: 11/21/2022]
Abstract
The exact residues within severe acute respiratory syndrome coronavirus (SARS-CoV) S1 protein and its receptor, human ACE2, involved in their interaction still remain largely undetermined. Identification of exact amino acid residues that are crucial for the interaction of S1 with ACE2 could provide working hypotheses for experimental studies and might be helpful for the development of antiviral inhibitor. In this paper, a molecular docking model of SARS-CoV S1 protein in complex with human ACE2 was constructed. The interacting residue pairs within this complex model and their contact types were also identified. Our model, supported by significant biochemical evidence, suggested receptor-binding residues were concentrated in two segments of S1 protein. In contrast, the interfacial residues in ACE2, though close to each other in tertiary structure, were found to be widely scattered in the primary sequence. In particular, the S1 residue ARG453 and ACE2 residue LYS341 might be the key residues in the complex formation.
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Affiliation(s)
- Yuan Zhang
- School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Nan Zheng
- Institute of Viral Disease Control and Prevention, Chinese CDC, Beijing 100052, China
| | - Pei Hao
- Shanghai Center for Bioinformation Technology, Shanghai 200235, China
| | - Ying Cao
- The Institute of Statistical Mathematics, 4-6-7 Minami-Azabu, Minato-ku, Tokyo 106, Japan
- Department of Biosystems Science, The Graduate University for Advanced Studies, Shonan Village, Hayama, Kanagawa 240-0193, Japan
| | - Yang Zhong
- School of Life Sciences, Fudan University, Shanghai 200433, China
- Corresponding author. Tel.: +86 21 55664436; fax: +86 21 65642468.
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Yap Y, Zhang X, Andonov A, He R. Structural analysis of inhibition mechanisms of aurintricarboxylic acid on SARS-CoV polymerase and other proteins. Comput Biol Chem 2005; 29:212-9. [PMID: 15979041 PMCID: PMC7106521 DOI: 10.1016/j.compbiolchem.2005.04.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Accepted: 04/08/2005] [Indexed: 12/17/2022]
Abstract
We recently published experimental results that indicated Aurintricarboxylic Acid (ATA) could selectively inhibit SARS-CoV replication inside host cells by greater than 1000 times. This inhibition suggested that ATA could be developed as potent anti-viral drug. Here, to extend our experimental observation, we have incorporated protein structural studies (with positive/negative controls) to investigate the potential binding modes/sites of ATA onto RNA-dependent RNA polymerase (RdRp) from SARS-CoV and other pathogenic positive-strand RNA-viruses, as well as other proteins in SARS-CoV based on the fact that ATA binds to Ca2+-activated neutral protease (m-calpain), the protein tyrosine phosphatase (PTP) and HIV integrase which have existing crystal structures. Eight regions with homologous 3D-conformation were derived for 10 proteins of interest. One of the region, Rbinding (754–766 in SARS-CoV's RdRp), located in the palm sub-domain mainly constituted of anti-parallel β-strand-turn-β-strand hairpin structures that covers two of the three RdRp catalytic sites (Asp 760, Asp761), was also predicted by molecular docking method (based on free energy of binding ΔG) to be important binding motif recognized by ATA. The existence of this strictly conserved region that incorporated catalytic residues, coupled with the homologous ATA binding pockets and their consistent ΔG values, suggested strongly ATA may be involved in an analogous inhibition mechanism of SARS-COV's RdRp in concomitant to the case in m-calpain, PTP and HIV integrase.
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Affiliation(s)
- YeeLeng Yap
- Institute Pasteur, Unité de Génétique des Génomes Bactériens, CNRS URA 2171, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France
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43
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Azizi A, Aucoin S, Tadesse H, Frost R, Ghorbani M, Soare C, Naas T, Diaz-Mitoma F. A combined nucleocapsid vaccine induces vigorous SARS-CD8+ T-cell immune responses. GENETIC VACCINES AND THERAPY 2005; 3:7. [PMID: 16115319 PMCID: PMC1249587 DOI: 10.1186/1479-0556-3-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Accepted: 08/22/2005] [Indexed: 12/04/2022]
Abstract
Several studies have shown that cell-mediated immune responses play a crucial role in controlling viral replication. As such, a candidate SARS vaccine should elicit broad CD8+ T-cell immune responses. Several groups of mice were immunized alone or in combination with SARS-nucleocapsid immunogen. A high level of specific SARS-CD8+ T-cell response was demonstrated in mice that received DNA encoding the SARS-nucleocapsid, protein and XIAP as an adjuvant. We also observed that co-administration of a plasmid expressing nucleocapsid, recombinant protein and montanide/CpG induces high antibody titers in immunized mice. Moreover, this vaccine approach merits further investigation as a potential candidate vaccine against SARS.
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Affiliation(s)
- Ali Azizi
- Infectious Disease and Vaccine Research Centre, Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Road, Ottawa, ON, K1H 8L1, Canada
- Department of Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M2, Canada
| | - Susan Aucoin
- Infectious Disease and Vaccine Research Centre, Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Road, Ottawa, ON, K1H 8L1, Canada
| | - Helina Tadesse
- Department of Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M2, Canada
| | - Rita Frost
- Infectious Disease and Vaccine Research Centre, Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Road, Ottawa, ON, K1H 8L1, Canada
| | - Masoud Ghorbani
- Infectious Disease and Vaccine Research Centre, Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Road, Ottawa, ON, K1H 8L1, Canada
| | - Catalina Soare
- Infectious Disease and Vaccine Research Centre, Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Road, Ottawa, ON, K1H 8L1, Canada
- Department of Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M2, Canada
| | - Turaya Naas
- Infectious Disease and Vaccine Research Centre, Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Road, Ottawa, ON, K1H 8L1, Canada
- Department of Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M2, Canada
| | - Francisco Diaz-Mitoma
- Infectious Disease and Vaccine Research Centre, Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Road, Ottawa, ON, K1H 8L1, Canada
- Department of Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M2, Canada
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Hua RH, Wang YF, Bu ZG, Zhou YJ, Ge JY, Wang XJ, Tong GZ. Identification and Antigenic Epitope Mapping of Immunodominant Region Amino Residues 510 to 672 on the Spike Protein of the Severe Acute Respiratory Syndrome Coronavirus. DNA Cell Biol 2005; 24:503-9. [PMID: 16101348 DOI: 10.1089/dna.2005.24.503] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The severe acute respiratory syndrome (SARS) is a newly emerging human infectious disease caused by the severe acute respiratory syndrome coronavirus (SARS-CoV). The spike (S) protein of SARS-CoV is a major virion structural protein. It plays an important role in the interaction with receptors and neutralizing antibodies. In this study, the S1 domain of the spike protein and three truncated fragments were expressed by fusion with GST in a pGEX-6p-1 vector. Western blot results demonstrated that the 510-672 fragment of the S1 domain is a linear epitope dominant region. To map the antigenic epitope of this linear epitope dominant region, a set of 16 partially overlapping fragments spanning the fragment were fused with GST and expressed. Four antigenic epitopes S1C3 (539-559), S1C4 (548-567), S1C7/8 (583-606), and S1C10/11 (607-630) were identified. Immunization of mice with each of the four antigenic epitope-fused proteins revealed that all four proteins could elicit spike protein specific antisera. All of them were able to bind to the surface domain of the whole spike protein expressed by recombinant baculovirus in insect cells. Identification of antigenic epitopes of the spike protein of SARS-CoV may provide the basis for the development of immunity-based prophylactic, therapeutic, and diagnostic clinical techniques for the severe acute respiratory syndrome.
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Affiliation(s)
- Rong-Hong Hua
- National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
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Zhao J, Wang W, Wang GF, Li Y, Zhuang H, Xu X, Ren F, Zhao Z, Gao XM. Development and evaluation of an enzyme-linked immunosorbent assay for detection of antibodies against the spike protein of SARS-coronavirus. J Clin Virol 2005; 33:12-8. [PMID: 15797360 PMCID: PMC7108335 DOI: 10.1016/j.jcv.2004.09.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2004] [Revised: 09/25/2004] [Accepted: 09/30/2004] [Indexed: 02/06/2023]
Abstract
BACKGROUND Severe acute respiratory syndrome (SARS) is caused by infection with SARS-associated coronavirus (CoV). Amino acid residues 450-650 of the spike (S) glycoprotein of SARS-CoV (S450-650) contains dominant epitopes for anti-viral antibodies (Abs) in patient sera. OBJECTIVES To develop and evaluate an ELISA system for detection of anti-S Abs in patient sera. STUDY DESIGN Express recombinant S450-650 in E. Coli and evaluate the sensitivity and specificity of an ELISA system based on the S450-650 polypeptide. RESULTS The S450-650-based ELISA detected IgG Abs in 41 out of 51 serum samples from 22 hospitalized patients with probable SARS, a result closely correlated with that obtained with a virus-based ELISA (r = 0.75, k = 0.8). Differential anti-S IgG responses were observed amongst SARS patients. Some of them produced anti-S Abs early during their infection, while others failed to make IgG Abs against the S450-650 polypeptide. None of the serum samples from 100 healthy blood donors was positive in the S450-650-based assay. CONCLUSION The S450-650-based ELISA can detect anti-S IgG Abs with high sensitivity and specificity.
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Affiliation(s)
- Jincun Zhao
- Department of Immunology, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100083, PR China
| | - Wei Wang
- Department of Immunology, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100083, PR China
| | - Guang-Fa Wang
- First Affiliated Hospital of Peking University, Peking University Health Science Center, 8 Xishiku Road, Beijing 100034, PR China
| | - Yonghua Li
- Department of Microbiology, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100083, PR China
| | - Hui Zhuang
- Department of Microbiology, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100083, PR China
| | - Xiaoyuan Xu
- First Affiliated Hospital of Peking University, Peking University Health Science Center, 8 Xishiku Road, Beijing 100034, PR China
| | - Furong Ren
- Beijing Red Cross Blood Center, 37 Beisanhuanzhong Road, Beijing 100088, PR China
| | - Zhendong Zhao
- Department of Immunology, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100083, PR China
- Corresponding author. Tel.: +86 10 8280 1156; fax: +86 10 8280 1156.
| | - Xiao-Ming Gao
- Department of Immunology, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100083, PR China
- Co-corresponding author.
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Pogrebnyak N, Golovkin M, Andrianov V, Spitsin S, Smirnov Y, Egolf R, Koprowski H. Severe acute respiratory syndrome (SARS) S protein production in plants: development of recombinant vaccine. Proc Natl Acad Sci U S A 2005; 102:9062-7. [PMID: 15956182 PMCID: PMC1157057 DOI: 10.1073/pnas.0503760102] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In view of a recent spread of severe acute respiratory syndrome (SARS), there is a high demand for production of a vaccine to prevent this disease. Recent studies indicate that SARS-coronavirus (CoV) spike protein (S protein) and its truncated fragments are considered the best candidates for generation of the recombinant vaccine. Toward the development of a safe, effective, and inexpensive vaccine candidate, we have expressed the N-terminal fragment of SARS-CoV S protein (S1) in tomato and low-nicotine tobacco plants. Incorporation of the S1 fragment into plant genomes as well as its transcription was confirmed by PCR and RT-PCR analyses. High levels of expression of recombinant S1 protein were observed in several transgenic lines by Western blot analysis using specific antibodies. Plant-derived antigen was evaluated to induce the systemic and mucosal immune responses in mice. Mice showed significantly increased levels of SARS-CoV-specific IgA after oral ingestion of tomato fruits expressing S1 protein. Sera of mice parenterally primed with tobacco-derived S1 protein revealed the presence of SARS-CoV-specific IgG as detected by Western blot and ELISA analysis.
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Affiliation(s)
- Natalia Pogrebnyak
- Biotechnology Foundation Laboratories, Thomas Jefferson University, Philadelphia, PA 19107-6799, USA
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47
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Zhao JC, Zhao ZD, Wang W, Gao XM. Prokaryotic expression, refolding, and purification of fragment 450-650 of the spike protein of SARS-coronavirus. Protein Expr Purif 2005; 39:169-74. [PMID: 15642467 PMCID: PMC7129930 DOI: 10.1016/j.pep.2004.10.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2004] [Revised: 10/01/2004] [Indexed: 11/20/2022]
Abstract
The spike (S) glycoprotein is one of the major structure proteins of SARS-associated coronavirus (CoV). Fragment 450-650 (S450-650) of the S protein contains receptor-binding domain and neutralizing epitopes. In this study, S450-650 was expressed with a histidine tag in Escherichia coli BL21. Bacterial inclusion bodies containing the recombinant S450-650 were solubilized with 8 M urea and then applied onto a Ni-nitrilotriacetic acid column. On-column refolding and purification was performed. Reduced glutathione and oxidized glutathione were included in the refolding buffer. In the wash and elution buffers, glycerol and glucose were necessary additives to prevent protein aggregation during purification. This refolding and purification procedure allowed production of S450-650 at up to 500 microg/ml in soluble form, which maintained appropriate antigenicity and immunogenicity. It was able to induce strong IgG responses in BALB/c mice. In Western blot assays, the recombinant S450-650 was recognized by monoclonal Ab against the His-tag and also sera from a convalescent SARS patient. S450-650-based ELISA system was able to detect anti-SARS-CoV IgG Abs in patient sera.
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Affiliation(s)
- Jin-Cun Zhao
- Department of Immunology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China.
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He Y, Lu H, Siddiqui P, Zhou Y, Jiang S. Receptor-binding domain of severe acute respiratory syndrome coronavirus spike protein contains multiple conformation-dependent epitopes that induce highly potent neutralizing antibodies. THE JOURNAL OF IMMUNOLOGY 2005; 174:4908-15. [PMID: 15814718 DOI: 10.4049/jimmunol.174.8.4908] [Citation(s) in RCA: 205] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The spike (S) protein of severe acute respiratory syndrome associated coronavirus (SARS-CoV) is a major antigenic determinant capable of inducing protective immunity. Recently, a small fragment on the SARS-CoV S protein (residues 318-510) was characterized as a minimal receptor-binding domain (RBD), which mediates virus binding to angiotensin-converting enzyme 2, the functional receptor on susceptible cells. In this study, we demonstrated that a fusion protein containing RBD linked to human IgG1 Fc fragment (designated RBD-Fc) induced high titer of RBD-specific Abs in the immunized mice. The mouse antisera effectively neutralized infection by both SARS-CoV and SARS pseudovirus with mean 50% neutralization titers of 1/15,360 and 1/24,737, respectively. The neutralization determinants on the RBD of S protein were characterized by a panel of 27 mAbs isolated from the immunized mice. Six groups of conformation-dependent epitopes, designated as Conf I-VI, and two adjacent linear epitopes were identified by ELISA and binding competition assays. The Conf IV and Conf V mAbs significantly blocked RBD-Fc binding to angiotensin-converting enzyme 2, suggesting that their epitopes overlap with the receptor-binding sites in the S protein. Most of the mAbs (23 of 25) that recognized the conformational epitopes possessed potent neutralizing activities against SARS pseudovirus with 50% neutralizing dose ranging from 0.005 to 6.569 microg/ml. Therefore, the RBD of SARS S protein contains multiple conformational epitopes capable of inducing potent neutralizing Ab responses, and is an important target site for developing vaccines and immunotherapeutics.
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Affiliation(s)
- Yuxian He
- Viral Immunology Laboratory, Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10021, USA
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49
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Chou THW, Wang S, Sakhatskyy PV, Mboudjeka I, Mboudoudjeck I, Lawrence JM, Huang S, Coley S, Yang B, Li J, Zhu Q, Lu S. Epitope mapping and biological function analysis of antibodies produced by immunization of mice with an inactivated Chinese isolate of severe acute respiratory syndrome-associated coronavirus (SARS-CoV). Virology 2005; 334:134-43. [PMID: 15749129 PMCID: PMC7111783 DOI: 10.1016/j.virol.2005.01.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Revised: 01/10/2005] [Accepted: 01/25/2005] [Indexed: 11/26/2022]
Abstract
Inactivated severe acute respiratory syndrome-associated coronavirus (SARS-CoV) has been tested as a candidate vaccine against the re-emergence of SARS. In order to understand the efficacy and safety of this approach, it is important to know the antibody specificities generated with inactivated SARS-CoV. In the current study, a panel of twelve monoclonal antibodies (mAbs) was established by immunizing Balb/c mice with the inactivated BJ01 strain of SARS-CoV isolated from the lung tissue of a SARS-infected Chinese patient. These mAbs could recognize SARS-CoV-infected cells by immunofluorescence analysis (IFA). Seven of them were mapped to the specific segments of recombinant spike (S) protein: six on S1 subunit (aa 12-798) and one on S2 subunit (aa 797-1192). High neutralizing titers against SARS-CoV were detected with two mAbs (1A5 and 2C5) targeting at a subdomain of S protein (aa 310-535), consistent with the previous report that this segment of S protein contains the major neutralizing domain. Some of these S-specific mAbs were able to recognize cleaved products of S protein in SARS-CoV-infected Vero E6 cells. None of the remaining five mAbs could recognize either of the recombinant S, N, M, or E antigens by ELISA. This study demonstrated that the inactivated SARS-CoV was able to preserve the immunogenicity of S protein including its major neutralizing domain. The relative ease with which these mAbs were generated against SARS-CoV virions further supports that subunit vaccination with S constructs may also be able to protect animals and perhaps humans. It is somewhat unexpected that no N-specific mAbs were identified albeit anti-N IgG was easily identified in SARS-CoV-infected patients. The availability of this panel of mAbs also provided potentially useful agents with applications in therapy, diagnosis, and basic research of SARS-CoV.
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Affiliation(s)
- Te-hui W Chou
- Laboratory of Nucleic Acid Vaccines, Department of Medicine, University of Massachusetts Medical School, 364 Plantation Street, Lazare Research Building, Worcester, MA 01605-2397, USA
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Cinatl J, Michaelis M, Hoever G, Preiser W, Doerr HW. Development of antiviral therapy for severe acute respiratory syndrome. Antiviral Res 2005; 66:81-97. [PMID: 15878786 PMCID: PMC7132397 DOI: 10.1016/j.antiviral.2005.03.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2005] [Revised: 03/16/2005] [Accepted: 03/17/2005] [Indexed: 02/09/2023]
Abstract
A new disease, the severe acute respiratory distress syndrome (SARS), caused by the SARS coronavirus (SARS-CoV), emerged at the beginning of 2003 and rapidly spread throughout the world. Although the disease had disappeared in June 2003 its re-emergence cannot be excluded. The development of vaccines against SARS-CoV may take years. Therefore, the availability of effective antiviral drugs against SARS-CoV may be crucial for the control of future SARS outbreaks. In this review, experimental and clinical data about potential anti-SARS drugs is summarised and discussed. Animal model studies will be needed to help to determine which interventions warrant controlled clinical testing.
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Affiliation(s)
- Jindrich Cinatl
- Institut für Medizinische Virologie, Klinikum der Johann Wolfgang Goethe-Universität, Paul Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany.
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