A #Chimeric #Sudan #VLP #Vaccine Candidate Produced by a Recombinant Baculovirus System Induces Specific Immune Responses in Mice and Horses (Viruses, abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Viruses. 2020 Jan 3;12(1). pii: E64. doi: 10.3390/v12010064.

A Chimeric Sudan Virus-Like Particle Vaccine Candidate Produced by a Recombinant Baculovirus System Induces Specific Immune Responses in Mice and Horses.

Wu F1, Zhang S1,2, Zhang Y1,2, Mo R1,3, Yan F1,4,5, Wang H1,6, Wong G7,8, Chi H1,4,5, Wang T1,4,5, Feng N1,4,5, Gao Y1,4,5, Xia X1,4,5, Zhao Y1,4,5, Yang S1,4,5.

Author information: 1 Institute of Military Veterinary Medicine, Academy of Military Medical Sciences, Changchun 130122, China. 2 College of Wildlife Resources, Northeast Forestry University, Harbin 150040, China. 3 Animal Science and Technology College, Jilin Agricultural University, Changchun 130118, China. 4 Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun 130000, China. 5 Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou 225009, China. 6 College of Veterinary Medicine, Jilin University, Changchun 130062, China. 7 Institute Pasteur of Shanghai, Chinese Academy of Science, Shanghai 20031, China. 8 Special Pathogens Program, Public Health Agency of Canada, Winnipeg, MB R3E3R2, Canada.

 

Abstract

Ebola virus infections lead to severe hemorrhagic fevers in humans and nonhuman primates; and human fatality rates are as high as 67%-90%. Since the Ebola virus was discovered in 1976, the only available treatments have been medical support or the emergency administration of experimental drugs. The absence of licensed vaccines and drugs against the Ebola virus impedes the prevention of viral infection. In this study, we generated recombinant baculoviruses (rBV) expressing the Sudan virus (SUDV) matrix structural protein (VP40) (rBV-VP40-VP40) or the SUDV glycoprotein (GP) (rBV-GP-GP), and SUDV virus-like particles (VLPs) were produced by co-infection of Sf9 cells with rBV-SUDV-VP40 and rBV-SUDV-GP. The expression of SUDV VP40 and GP in SUDV VLPs was demonstrated by IFA and Western blot analysis. Electron microscopy results demonstrated that SUDV VLPs had a filamentous morphology. The immunogenicity of SUDV VLPs produced in insect cells was evaluated by the immunization of mice. The analysis of antibody responses showed that mice vaccinated with SUDV VLPs and the adjuvant Montanide ISA 201 produced SUDV GP-specific IgG antibodies. Sera from SUDV VLP-immunized mice were able to block infection by SUDV GP pseudotyped HIV, indicating that a neutralizing antibody against the SUDV GP protein was produced. Furthermore, the activation of B cells in the group immunized with VLPs mixed with Montanide ISA 201 was significant one week after the primary immunization. Vaccination with the SUDV VLPs markedly increased the frequency of antigen-specific cells secreting type 1 and type 2 cytokines. To study the therapeutic effects of SUDV antibodies, horses were immunized with SUDV VLPs emulsified in Freund’s complete adjuvant or Freund’s incomplete adjuvant. The results showed that horses could produce SUDV GP-specific antibodies and neutralizing antibodies. These results showed that SUDV VLPs demonstrate excellent immunogenicity and represent a promising approach for vaccine development against SUDV infection. Further, these horse anti-SUDV purified immunoglobulins lay a foundation for SUDV therapeutic drug research.

KEYWORDS: Sudan virus; horse; mice; purified IgG; vaccine; virus-like particle

PMID: 31947873 DOI: 10.3390/v12010064

Keywords: Ebolavirus; Sudan virus; Vaccines; Animal models.

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A Novel #Bacterium-Like #Particle-Based #Vaccine Displaying the #SUDV Glycoprotein Induces Potent Humoral and Cellular Immune Responses in Mice (Viruses, abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Viruses. 2019 Dec 11;11(12). pii: E1149. doi: 10.3390/v11121149.

A Novel Bacterium-Like Particle-Based Vaccine Displaying the SUDV Glycoprotein Induces Potent Humoral and Cellular Immune Responses in Mice.

Xu S1,2, Jiao C2, Jin H2,3, Li W2,3, Li E2,4, Cao Z2,3, Shi Z1,2, Yan F2, Zhang S2,5, He H6, Chi H2,7, Feng N2,7, Zhao Y2,7, Gao Y2,7, Yang S2,7, Wang J1, Wang H2,3,7, Xia X2,7.

Author information: 1 College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China. 2 Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun 130122, China. 3 Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun 130062, China. 4 College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China. 5 College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China. 6 Key Laboratory of Animal Resistant Biology of Shandong, Ruminant Diseases Research Center, College of Life Sciences, Shandong Normal University, Jinan 250014, China. 7 Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225000, China.

 

Abstract

Sudan virus (SUDV) causes severe lethal hemorrhagic fever in humans and nonhuman primates. The most effective and economical way to protect against Sudan ebolavirus disease is prophylactic vaccination. However, there are no licensed vaccines to prevent SUDV infections. In this study, a bacterium-like particle (BLP)-based vaccine displaying the extracellular domain of the SUDV glycoprotein (eGP) was developed based on a gram-positive enhancer matrix-protein anchor (GEM-PA) surface display system. Expression of the recombinant GEM-displayed eGP (eGP-PA-GEM) was verified by Western blotting and immunofluorescence assays. The SUDV BLPs (SBLPs), which were mixed with Montanide ISA 201VG plus Poly (I:C) combined adjuvant, could induce high SUDV GP-specific IgG titers of up to 1:40,960 and robust virus-neutralizing antibody titers reached 1:460. The SBLP also elicited T-helper 1 (Th1) and T-helper 2 (Th2) cell-mediated immunity. These data indicate that the SBLP subunit vaccine has the potential to be developed into a promising candidate vaccine against SUDV infections.

KEYWORDS: SUDV; bacterium-like particles; eGP; immune response; subunit vaccine

PMID: 31835785 DOI: 10.3390/v11121149

Keywords: Ebola; Sudan virus; Vaccines; Animal models.

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#Serological Evidence of #Exposure to #Ebolaviruses in Domestic #Pigs from #Guinea (Tranbsound Emerg Dis., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Transbound Emerg Dis. 2019 Oct 18. doi: 10.1111/tbed.13391. [Epub ahead of print]

Serological Evidence of Exposure to Ebolaviruses in Domestic Pigs from Guinea.

Fischer K1, Camara A2, Troupin C2, Fehling SK3, Strecker T3, Groschup MH1, Tordo N2, Diederich S1.

Author information: 1 Friedrich-Loeffler-Institut, Institute of Novel and Emerging Infectious Diseases, Greifswald – Insel Riems, Germany. 2 Institut Pasteur de Guineé, Conakry, Guinea. 3 Institute of Virology, Philipps University of Marburg, Marburg, Germany.

 

Abstract

The genus Ebolavirus comprises several virus species with zoonotic potential and varying pathogenicity for humans. Ebolaviruses are considered to circulate in wildlife with occasional spillover events into the human population which then often leads to severe disease outbreaks. Several studies indicate a significant role of bats as reservoir hosts in the ebolavirus ecology. However, pigs from the Philippines have been found to be naturally infected with Reston virus (RESTV), an ebolavirus that is thought to only cause asymptomatic infections in humans. The recent report of ebolavirus-specific antibodies in pigs from Sierra Leone further supports natural infection of pigs with ebolaviruses. However, susceptibility of pigs to highly pathogenic Ebola virus (EBOV) was only shown under experimental settings and evidence for natural infection of pigs with EBOV is currently lacking. Between October and December 2017, we collected 308 serum samples from pigs in Guinea, West Africa, and tested for the presence of ebolavirus-specific antibodies with different serological assays. Besides reactivity to EBOV nucleoproteins in ELISA and Western Blot for 19 (6.2%) and 13 (4.2%) samples respectively, four sera recognized Sudan virus (SUDV) NP in Western blot. Furthermore, four samples specifically detected EBOV or SUDV glycoprotein (GP) in an indirect immunofluorescence assay under native conditions. Virus neutralization assay based on EBOV (Mayinga isolate) revealed five weakly neutralizing sera. The finding of (cross-) reactive and weakly neutralizing antibodies suggests the exposure of pigs from Guinea to ebolaviruses or ebola-like viruses with their pathogenicity as well as their zoonotic potential remaining unknown. Future studies should investigate whether pigs can act as an amplifying host for ebolaviruses and whether there is a risk for spillover events.

© 2019 Blackwell Verlag GmbH.

KEYWORDS: ELISA; Ebola; West Africa; antibodies; ebolaviruses; neutralization test; pigs; serology

PMID: 31627257 DOI: 10.1111/tbed.13391

Keywords: Ebola; Sudan Virus; Serology; Seroprevalence; Pigs; Guinea.

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#Sudan #Ebolavirus VP35-NP Crystal Structure Reveals a Potential Target for Pan-Filovirus Treatment (mBio, abstract)

[Source: Mbio, full page: (LINK). Abstract, edited.]

Sudan Ebolavirus VP35-NP Crystal Structure Reveals a Potential Target for Pan-Filovirus Treatment

Sara Landeras-Bueno, Shun-ichiro Oda, Michael J. Norris, Zhe Li Salie, Javier Guenaga, Richard T. Wyatt, Erica Ollmann Saphire

Gaya Amarasinghe, Invited Editor, Thomas E. Smithgall, Editor

DOI: 10.1128/mBio.00734-19

 

ABSTRACT

The filoviruses are etiological agents of life-threatening hemorrhagic fever with high mortality rate and risk of potential outbreak. Among members of this family, the Ebola (EBOV), Sudan (SUDV), and Marburg (MARV) viruses are considered the most pathogenic for humans. The ebolavirus nucleoprotein (NP) is the most abundant protein in infected cells and is essential for viral transcription and replication; thus, it represents an attractive target for therapeutic intervention. Here, we present the structure of SUDV NP in complex with the amino-terminal portion of the phosphoprotein VP35 at 2.3 Å. This structure captures VP35 chaperoning SUDV NP in a monomeric and RNA-free state. This transient state has been proposed to be key to maintaining a pool of monomeric and RNA-free NPs prior to NP-NP polymerization and encapsidation of the viral RNA genome. This structure also reveals a newly visualized interaction between NP and VP35, a well-defined beta sheet that is not present in previous structures. Affinity binding assays demonstrate that this beta sheet is essential for maintaining the high-affinity interaction between VP35 and a hydrophobic pocket on SUDV NP, and electron microscopy indicates the importance of this binding interaction to the oligomeric state and assembly of NP in human cells. Complementary structure-directed mutagenesis identifies critical residues conserved across the filovirus family that could be targeted by broadly effective antivirals.

 

IMPORTANCE

Outbreaks of the filoviruses can be unpredictable in timing, location, and identity of the causative virus, with each of Ebola virus, Sudan virus, Bundibugyo virus, and Marburg virus reemerging in the last several years to cause human disease with 30 to 90% lethality. The 2014–2016 outbreak in particular, with nearly 30,000 patients, highlighted the ability of these viruses to emerge unexpectedly and spread rapidly. Two ebolavirus outbreaks have emerged this year, yet we still lack FDA-approved drugs with pan-filovirus activity to treat existing and emergent ebolaviruses. For all filoviruses, the interaction between the nucleoprotein and the phosphoprotein is essential for the virus life cycle and is a potential target for therapeutic intervention. In this report, we describe the crystal structure of the SUDV nucleoprotein with the interacting domain of the viral phosphoprotein, and we identify residues critical for high-affinity interaction and for control of the oligomeric state of the nucleoprotein. Structural comparison of this heterodimer with other members of the filovirus family allowed us to find conserved and essential atomic features that will facilitate understanding of the virus life cycle and the rational design of antivirals.

Keywords: Ebola; Filovirus; Sudan virus.

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Cross-reactive neutralizing #human #survivor monoclonal #antibody BDBV223 targets the #ebolavirus stalk (Nat Commun., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Nat Commun. 2019 Apr 17;10(1):1788. doi: 10.1038/s41467-019-09732-7.

Cross-reactive neutralizing human survivor monoclonal antibody BDBV223 targets the ebolavirus stalk.

King LB1, West BR1, Moyer CL1, Gilchuk P2, Flyak A3, Ilinykh PA4,5, Bombardi R2, Hui S1, Huang K4,5, Bukreyev A4,5,6, Crowe JE Jr2,3, Saphire EO7,8,9.

Author information: 1 Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA. 2 Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, 37232, USA. 3 Departments of Pediatrics, Pathology, and Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA. 4 Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA. 5 Galveston National Laboratory, Galveston, TX, 77555, USA. 6 Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA. 7 Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA. erica@lji.org. 8 Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA. erica@lji.org. 9 La Jolla Institute for Immunology La Jolla, CA, 92037, USA. erica@lji.org.

 

Abstract

Three Ebolavirus genus viruses cause lethal disease and lack targeted therapeutics: Ebola virus, Sudan virus and Bundibugyo virus. Monoclonal antibody (mAb) cocktails against the surface glycoprotein (GP) present a potential therapeutic strategy. Here we report two crystal structures of the antibody BDBV223, alone and complexed with its GP2 stalk epitope, an interesting site for therapeutic/vaccine design due to its high sequence conservation among ebolaviruses. BDBV223, identified in a human survivor of Bundibugyo virus disease, neutralizes both Bundibugyo virus and Ebola virus, but not Sudan virus. Importantly, the structure suggests that BDBV223 binding interferes with both the trimeric bundle assembly of GP and the viral membrane by stabilizing a conformation in which the monomers are separated by GP lifting or bending. Targeted mutagenesis of BDBV223 to enhance SUDV GP recognition indicates that additional determinants of antibody binding likely lie outside the visualized interactions, and perhaps involve quaternary assembly or membrane-interacting regions.

PMID: 30996276 DOI: 10.1038/s41467-019-09732-7

Keywords: Ebola; Monoclonal antibodies.

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#Generation and Characterization of Anti- #Filovirus #Nucleoprotein Monoclonal #Antibodies (Viruses, abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Viruses. 2019 Mar 14;11(3). pii: E259. doi: 10.3390/v11030259.

Generation and Characterization of Anti-Filovirus Nucleoprotein Monoclonal Antibodies.

Rahim MN1,2, Wang M3, Wang T4, He S5, Griffin BD6, Kobasa D7,8, Yang R9, Du Z10, Qiu X11,12.

Author information: 1 Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, MB, R3E 3R2, Canada. mdniaz.rahim@canada.ca. 2 Department of Medical Microbiology, University of Manitoba, 745 Bannatyne Avenue, Winnipeg, MB, R3E 0J9, Canada. mdniaz.rahim@canada.ca. 3 State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China. yrf007@sina.com. 4 State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China. wtwangtongqz@163.com. 5 Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, MB, R3E 3R2, Canada. shihua.he@canada.ca. 6 Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, MB, R3E 3R2, Canada. bryan.griffin@canada.ca. 7 Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, MB, R3E 3R2, Canada. darwyn.kobasa@canada.ca. 8 Department of Medical Microbiology, University of Manitoba, 745 Bannatyne Avenue, Winnipeg, MB, R3E 0J9, Canada. darwyn.kobasa@canada.ca. 9 State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China. ruifuyang@gmail.com. 10 State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China. zongmindu@gmail.com. 11 Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, MB, R3E 3R2, Canada. Xiangguo.Qiu@canada.ca. 12 Department of Medical Microbiology, University of Manitoba, 745 Bannatyne Avenue, Winnipeg, MB, R3E 0J9, Canada. Xiangguo.Qiu@canada.ca.

 

Abstract

Filoviruses cause lethal hemorrhagic fever in humans. The filovirus nucleoprotein (NP) is expressed in high abundance in infected cells and is essential for virus replication. To generate anti-filovirus monoclonal antibodies (mAbs) against the NP, mice were immunized with peptides known as B-cell epitopes corresponding to different filovirus NPs, and hybridomas were screened using FLAG-tagged filovirus NP constructs. Numerous mAbs were identified, isotyped, and characterized. The anti-NP mAbs demonstrated different ranges of binding affinities to various filovirus NPs. Most of the clones specifically detected both recombinant and wild-type NPs from different filoviruses, including Ebola (EBOV), Sudan (SUDV), Bundibugyo (BDBV), Marburg (MARV), Tai Forest (TAFV), and Reston (RESTV) viruses in western blot analysis. The mAbs were also able to detect native NPs within the cytoplasm of infected cells by immunofluorescence confocal microscopy. Thus, this panel of mAbs represents an important set of tools that may be potentially useful for diagnosing filovirus infection, characterizing virus replication, and detecting NP⁻host protein interactions.

KEYWORDS: Bundibugyo (BDBV); Ebola (EBOV); Marburg (MARV); Reston (RESTV) viruses; Sudan (SUDV); Tai Forest (TAFV); mAb (monoclonal antibody)

PMID: 30875741 DOI: 10.3390/v11030259

Keywords: Filovirus; Monoclonal antibodies; Ebola; Marburg; Sudan virus; Reston Virus.

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Structural basis of broad #ebolavirus #neutralization by a #human #survivor #antibody (Nat Struct Mol Biol., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Nat Struct Mol Biol. 2019 Mar 4. doi: 10.1038/s41594-019-0191-4. [Epub ahead of print]

Structural basis of broad ebolavirus neutralization by a human survivor antibody.

West BR1, Wec AZ2,3, Moyer CL1,4, Fusco ML1, Ilinykh PA5,6, Huang K5,6, Wirchnianski AS2, James RM7, Herbert AS7, Hui S1, Goodwin E3, Howell KA8, Kailasan S8, Aman MJ8, Walker LM3, Dye JM7, Bukreyev A5,6,9, Chandran K10, Saphire EO11,12.

Author information: 1 Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA. 2 Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA. 3 Adimab LLC, Lebanon, NH, USA. 4 Mapp Biopharmaceutical, San Diego, CA, USA. 5 Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA. 6 Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX, USA. 7 Division of Virology, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, USA. 8 Integrated Biotherapeutics, Rockville, MD, USA. 9 Department of Immunology and Microbiology, University of Texas Medical Branch, Galveston, TX, USA. 10 Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA. kartik.chandran@einstein.yu.edu. 11 Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA. erica@scripps.edu. 12 Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA. erica@scripps.edu.

 

Abstract

The structural features that govern broad-spectrum activity of broadly neutralizing anti-ebolavirus antibodies (Abs) outside of the internal fusion loop epitope are currently unknown. Here we describe the structure of a broadly neutralizing human monoclonal Ab (mAb), ADI-15946, which was identified in a human survivor of the 2013-2016 outbreak. The crystal structure of ADI-15946 in complex with cleaved Ebola virus glycoprotein (EBOV GPCL) reveals that binding of the mAb structurally mimics the conserved interaction between the EBOV GP core and its glycan cap β17-β18 loop to inhibit infection. Both endosomal proteolysis of EBOV GP and binding of mAb FVM09 displace this loop, thereby increasing exposure of ADI-15946’s conserved epitope and enhancing neutralization. Our work also mapped the paratope of ADI-15946, thereby explaining reduced activity against Sudan virus, which enabled rational, structure-guided engineering to enhance binding and neutralization of Sudan virus while retaining the parental activity against EBOV and Bundibugyo virus.

PMID: 30833785 DOI: 10.1038/s41594-019-0191-4

Keywords: Ebolavirus; Sudan Virus; Bundibugyio virus; Monoclonal antibodies.

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