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.



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.


#H7N9 #Influenza Virus Containing a #Polybasic HA Cleavage Site Requires Minimal Host #Adaptation to Obtain a Highly Pathogenic Disease Phenotype in Mice (Viruses, abstract)

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

Viruses. 2020 Jan 5;12(1). pii: E65. doi: 10.3390/v12010065.

H7N9 Influenza Virus Containing a Polybasic HA Cleavage Site Requires Minimal Host Adaptation to Obtain a Highly Pathogenic Disease Phenotype in Mice.

Chan M1, Leung A1, Hisanaga T2, Pickering B2,3, Griffin BD1,3, Vendramelli R1, Tailor N1, Wong G4,5, Bi Y6, Babiuk S2, Berhane Y2, Kobasa D1,3.

Author information: 1 Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, MB R3E 3R2, Canada. 2 National Centre for Foreign Animal Disease, Canadian Food Inspection Agency, Winnipeg, MB R3E 3M4, Canada. 3 Department of Medical Microbiology and Infectious Diseases, University of Manitoba, 745 Bannatyne Avenue, Winnipeg, MB R3E 0J9, Canada. 4 Institut Pasteur of Shanghai, Chinese Academy of Sciences, Life Science Research Building 320 Yueyang Road, Xuhui District, Shanghai 200031, China. 5 Département de microbiologie-infectiologie et d’immunologie, Université Laval, 1050 avenue de la Médecine, QC G1V 0A6, Canada. 6 CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Influenza Research and Early-warning (CASCIRE), Chinese Academy of Sciences, Beijing 100101, China.



Low pathogenic avian influenza (LPAI) H7N9 viruses have recently evolved to gain a polybasic cleavage site in the hemagglutinin (HA) protein, resulting in variants with increased lethality in poultry that meet the criteria for highly pathogenic avian influenza (HPAI) viruses. Both LPAI and HPAI variants can cause severe disease in humans (case fatality rate of ~40%). Here, we investigated the virulence of HPAI H7N9 viruses containing a polybasic HA cleavage site (H7N9-PBC) in mice. Inoculation of mice with H7N9-PBC did not result in observable disease; however, mice inoculated with a mouse-adapted version of this virus, generated by a single passage in mice, caused uniformly lethal disease. In addition to the PBC site, we identified three other mutations that are important for host-adaptation and virulence in mice: HA (A452T), PA (D347G), and PB2 (M483K). Using reverse genetics, we confirmed that the HA mutation was the most critical for increased virulence in mice. Our study identifies additional disease determinants in a mammalian model for HPAI H7N9 virus. Furthermore, the ease displayed by the virus to adapt to a new host highlights the potential for H7N9-PBC viruses to rapidly acquire mutations that may enhance their risk to humans or other animal species.

KEYWORDS: H7N9; HPAI; influenza virus; mammalian adaptation; mice; polybasic HA

PMID: 31948040 DOI: 10.3390/v12010065

Keywords: Avian Influenza; H7N9; Viral pathogenesis; Animal models.


Assessing the #susceptibility of highly pathogenic #avian #influenza #H5N1 viruses to #oseltamivir using embryonated chicken #eggs (Indian J Med Res., abstract)

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

Indian J Med Res. 2019 Nov;150(5):486-491. doi: 10.4103/ijmr.IJMR_845_18.

Assessing the susceptibility of highly pathogenic avian influenza H5N1 viruses to oseltamivir using embryonated chicken eggs.

Tare DS1, Kode SS1, Hurt AC2, Pawar SD3.

Author information: 1 Avian Influenza Group, ICMR-National Institute of Virology-Microbial Containment Complex, Pune, Maharashtra, India. 2 WHO Collaborating Centre for Reference & Research on Influenza (VIDRL), Peter Doherty Institute for Infection & Immunity, Melbourne VIC 3000, Australia. 3 ICMR-National Institute of Virology-Mumbai Unit, Mumbai, Maharashtra, India.




The susceptibility of influenza viruses to neuraminidase inhibitors (NAIs) is studied using enzyme-based assays, sequence analysis and in vitro and in vivo studies. Oseltamivir carboxylate (OC) is the active prodrug of the NAI oseltamivir. There is lack of information on the use of embryonated chicken eggs for studying susceptibility of highly pathogenic avian influenza (HPAI) H5N1 viruses to antiviral drugs. The aim of the present study was to assess the use of 10 day old embryonated chicken eggs for studying antiviral susceptibility of HPAI H5N1 viruses.


Two HPAI H5N1 viruses isolated from India were used in the study. Fluorescence-based NAI assay was performed to determine antiviral susceptibility of these viruses. In ovo antiviral assays were carried out using 10 day old embryonated chicken eggs. The virus dilutions were incubated with 14 μg/ml of OC and inoculated in the allantoic cavity. In the eggs, 50 per cent egg infectious dose (EID50) titres as well as mortality were quantitated.


The two viruses used were susceptible to OC in the NAI assay. It was found that there was a significant drop in EID50titres; however, no significant protection from mortality after OC treatment was observed.


By measuring viral titres, the egg model was suitable to study the susceptibility of HPAI viruses to antiviral drugs along with NAI assay. The present study highlights the use of eggs as a model to study susceptibility of HPAI viruses to OC.

KEYWORDS: Antivirals – embryonated chicken eggs – H5N1 – highly pathogenic avian influenza – oseltamivir

PMID: 31939392 DOI: 10.4103/ijmr.IJMR_845_18

Keywords: Antivirals; Drugs resistance; Avian Influenza; H5N1; Animal models.


A molecularly engineered #antiviral banana #lectin inhibits #fusion and is efficacious against #influenza virus infection in vivo (Proc Natl Acad Sci USA, abstract)

[Source: Proceedings of the National Academy of Sciences of the United States of America, full page: (LINK). Abstract, edited.]

A molecularly engineered antiviral banana lectin inhibits fusion and is efficacious against influenza virus infection in vivo

Evelyn M. Covés-Datson, Steven R. King, Maureen Legendre, Auroni Gupta, Susana M. Chan, Emily Gitlin, Vikram V. Kulkarni, Jezreel Pantaleón García, Donald F. Smee, Elke Lipka, Scott E. Evans, E. Bart Tarbet, Akira Ono, and David M. Markovitz

PNAS first published January 13, 2020 / DOI: https://doi.org/10.1073/pnas.1915152117

Edited by Peter Palese, Icahn School of Medicine at Mount Sinai, New York, NY, and approved December 19, 2019 (received for review September 8, 2019)



There is a pressing need for new antiinfluenza therapeutic agents. We show that a molecularly engineered banana lectin (carbohydrate-binding protein) has broad-spectrum activity against all influenza strains tested, including drug-resistant and currently circulating strains; is safe upon repeated administration in mice; and, moreover, is efficacious at treating lethal influenza infection via clinically pertinent routes of administration. We demonstrate that the lectin binds to the viral hemagglutinin glycoprotein and exerts its primary antiviral effect via inhibition of an early stage of the viral life cycle, viral membrane fusion to the host endosomal membrane. Our findings indicate that this engineered lectin, which has a mechanism of action quite distinct from the presently available agents, has potential as an antiinfluenza agent.



There is a strong need for a new broad-spectrum antiinfluenza therapeutic, as vaccination and existing treatments are only moderately effective. We previously engineered a lectin, H84T banana lectin (H84T), to retain broad-spectrum activity against multiple influenza strains, including pandemic and avian, while largely eliminating the potentially harmful mitogenicity of the parent compound. The amino acid mutation at position 84 from histidine to threonine minimizes the mitogenicity of the wild-type lectin while maintaining antiinfluenza activity in vitro. We now report that in a lethal mouse model H84T is indeed nonmitogenic, and both early and delayed therapeutic administration of H84T intraperitoneally are highly protective, as is H84T administered subcutaneously. Mechanistically, attachment, which we anticipated to be inhibited by H84T, was only somewhat decreased by the lectin. Instead, H84T is internalized into the late endosomal/lysosomal compartment and inhibits virus–endosome fusion. These studies reveal that H84T is efficacious against influenza virus in vivo, and that the loss of mitogenicity seen previously in tissue culture is also seen in vivo, underscoring the potential utility of H84T as a broad-spectrum antiinfluenza agent.

influenza virus – hemagglutinin – membrane fusion – lectin – antiviral

Keywords: Antivirals; Banana lectin; Influenza A; Animal models.


Modification of neutralizing epitopes of #hemagglutinin for the #development of broadly protective #H9N2 #vaccine (Vaccine, abstract)

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

Vaccine. 2020 Jan 7. pii: S0264-410X(19)31634-2. doi: 10.1016/j.vaccine.2019.11.080. [Epub ahead of print]

Modification of neutralizing epitopes of hemagglutinin for the development of broadly protective H9N2 vaccine.

Poh ZW1, Wang Z1, Kumar SR1, Yong HY1, Prabakaran M2.

Author information: 1 Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore. 2 Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore. Electronic address: prabakar@tll.org.sg.



The H9N2 avian influenza viruses cause significant economic losses in poultry worldwide and could potentially cause human pandemic. Currently, the available vaccines have limited efficacy due to antigenic drift of H9N2. To improve vaccine efficacy, we developed monovalent vaccine strain via the modification of neutralizing epitopes on hemagglutinin (HA) to broaden the protection against H9N2 viruses. In this study, single and multiple mutation were introduced to amino acid at position 148, 150 (site I) and 183, 186, 188 (site II) on the full-length HA gene of H9N2 strain (A/Hong Kong/33982/2009). These mutant HA constructs were displayed on the baculovirus surface (BacH9), and evaluated for their cross-protective efficacy against H9N2 viruses in a mouse model. Our findings indicate that mice immunized with multiple BacH9 mutant constructs (148-150 183 and 186) induced cross-protective immunity against circulating H9N2 in the viral challenge study and prove to be a promising vaccine candidate for H9N2.

Copyright © 2019 Elsevier Ltd. All rights reserved.

KEYWORDS: Baculoviral display HA; H9N2; Monovalent vaccine strain; Neutralizing epitope

PMID: 31924429 DOI: 10.1016/j.vaccine.2019.11.080

Keywords: Avian Influenza; H9N2; Vaccines; Animal models.


Comparative #therapeutic efficacy of #remdesivir and combination #lopinavir#, ritonavir, and #interferon beta against #MERS-CoV (Nat Commun., abstract)

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

Comparative therapeutic efficacy of remdesivir and combination lopinavir, ritonavir, and interferon beta against MERS-CoV

Timothy P. Sheahan, Amy C. Sims, Sarah R. Leist, Alexandra Schäfer, John Won, Ariane J. Brown, Stephanie A. Montgomery, Alison Hogg, Darius Babusis, Michael O. Clarke, Jamie E. Spahn, Laura Bauer, Scott Sellers, Danielle Porter, Joy Y. Feng, Tomas Cihlar, Robert Jordan, Mark R. Denison & Ralph S. Baric

Nature Communications, volume 11, Article number: 222 (2020)



Middle East respiratory syndrome coronavirus (MERS-CoV) is the causative agent of a severe respiratory disease associated with more than 2468 human infections and over 851 deaths in 27 countries since 2012. There are no approved treatments for MERS-CoV infection although a combination of lopinavir, ritonavir and interferon beta (LPV/RTV-IFNb) is currently being evaluated in humans in the Kingdom of Saudi Arabia. Here, we show that remdesivir (RDV) and IFNb have superior antiviral activity to LPV and RTV in vitro. In mice, both prophylactic and therapeutic RDV improve pulmonary function and reduce lung viral loads and severe lung pathology. In contrast, prophylactic LPV/RTV-IFNb slightly reduces viral loads without impacting other disease parameters. Therapeutic LPV/RTV-IFNb improves pulmonary function but does not reduce virus replication or severe lung pathology. Thus, we provide in vivo evidence of the potential for RDV to treat MERS-CoV infections.

Keywords: Antivirals; Remdesivir; Lopinavir; Ritonavir; Interferons; MERS-CoV; Animal models.


Comparative #Pathogenicity and #Transmissibility of #H1N1pdm09, #Avian #H5N1, and #Human #H7N9 #Influenza Viruses in Tree #Shrews (Front Microbiol., abstract)

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

Front Microbiol. 2019 Dec 20;10:2955. doi: 10.3389/fmicb.2019.02955. eCollection 2019.

Comparative Pathogenicity and Transmissibility of Pandemic H1N1, Avian H5N1, and Human H7N9 Influenza Viruses in Tree Shrews.

Xu S1, Li X1, Yang J1, Wang Z1, Jia Y1, Han L1, Wang L1, Zhu Q1.

Author information: 1 State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China.



Influenza A viruses (IAVs) continuously challenge the poultry industry and human health. Studies of IAVs are still hampered by the availability of suitable animal models. Chinese tree shrews (Tupaia belangeri chinensis) are closely related to primates physiologically and genetically, which make them a potential animal model for human diseases. In this study, we comprehensively evaluated infectivity and transmissibility in Chinese tree shrews by using pandemic H1N1 (A/Sichuan/1/2009, pdmH1N1), avian-origin H5N1 (A/Chicken/Gansu/2/2012, H5N1) and early human-origin H7N9 (A/Suzhou/SZ19/2014, H7N9) IAVs. We found that these viruses replicated efficiently in primary tree shrew cells and tree shrews without prior adaption. Pathological lesions in the lungs of the infected tree shrews were severe on day 3 post-inoculation, although clinic symptoms were self-limiting. The pdmH1N1 and H7N9 viruses, but not the H5N1 virus, transmitted among tree shrews by direct contact. Interestingly, we also observed that unadapted H7N9 virus could transmit from tree shrews to naïve guinea pigs. Virus-inoculated tree shrews generated a strong humoral immune response and were protected from challenge with homologous virus. Taken together, our findings suggest the Chinese tree shrew would be a useful mammalian model to study the pathogenesis and transmission of IAVs.

Copyright © 2019 Xu, Li, Yang, Wang, Jia, Han, Wang and Zhu.

KEYWORDS: H1N1; H5N1; H7N9; infectivity; transmissibility; tree shrew

PMID: 31921093 PMCID: PMC6933948 DOI: 10.3389/fmicb.2019.02955

Keywords: Influenza A; H7N9; H5N1; H1N1pdm09; Animal models.