Single immunization with recombinant ACAM2000 vaccinia viruses expressing the spike and the nucleocapsid proteins protect hamsters against SARS-CoV-2 caused clinical disease

SUMMARYIncreasing cases of SARS-CoV-2 breakthrough infections from immunization with predominantly spike protein based COVID-19 vaccines highlight the need for alternative vaccines using different platforms and/or antigens. In this study, we expressed SARS-CoV-2 spike and nucleocapsid proteins in a novel vaccinia virus ACAM2000 platform (rACAM2000). Following a single intramuscular immunization, the rACAM2000 co-expressing the spike and nucleocapsid proteins induced significantly improved protection against SARS-CoV-2 challenge in comparison to rACAM2000 expressing the individual proteins in a hamster model, as shown by reduced weight loss and quicker recovery time. The protection was associated with reduced viral loads, increased neutralizing antibody titre and reduced neutrophil-to-lymphocyte ratio. Thus, our study demonstrates that the rACAM2000 expressing a combination of the spike and nucleocapsid antigens is a promising COVID-19 vaccine candidate and further studies will investigate if the rACAM2000 vaccine candidate can induce a long lasting immunity against infection of SARS-CoV-2 variants of concern.

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Immunization with RBD-P2 and N protects against SARS-CoV-2 in nonhuman primates

Science Advances ◽

10.1126/sciadv.abg7156 ◽

2021 ◽

Vol 7 (22) ◽

pp. eabg7156

Author(s):

So-Hee Hong ◽

Hanseul Oh ◽

Yong Wook Park ◽

Hye Won Kwak ◽

Eun Young Oh ◽

...

Keyword(s):

Nucleocapsid Protein ◽

Nonhuman Primates ◽

Vaccine Candidate ◽

Statistical Significance ◽

Neutralizing Antibody ◽

Spike Protein ◽

Vaccine Candidates ◽

Cell Responses ◽

Antibody Levels ◽

Further Development

Since the emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), various vaccines are being developed, with most vaccine candidates focusing on the viral spike protein. Here, we developed a previously unknown subunit vaccine comprising the receptor binding domain (RBD) of the spike protein fused with the tetanus toxoid epitope P2 (RBD-P2) and tested its efficacy in rodents and nonhuman primates (NHPs). We also investigated whether the SARS-CoV-2 nucleocapsid protein (N) could increase vaccine efficacy. Immunization with N and RBD-P2 (RBDP2/N) + alum increased T cell responses in mice and neutralizing antibody levels in rats compared with those obtained using RBD-P2 + alum. Furthermore, in NHPs, RBD-P2/N + alum induced slightly faster SARS-CoV-2 clearance than that induced by RBD-P2 + alum, albeit without statistical significance. Our study supports further development of RBD-P2 as a vaccine candidate against SARS-CoV-2. Also, it provides insights regarding the use of N in protein-based vaccines against SARS-CoV-2.

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Soluble Spike DNA Vaccine Provides Long-Term Protective Immunity against SARS-CoV-2 in Mice and Nonhuman Primates

Vaccines ◽

10.3390/vaccines9040307 ◽

2021 ◽

Vol 9 (4) ◽

pp. 307

Author(s):

Yong Bok Seo ◽

You Suk Suh ◽

Ji In Ryu ◽

Hwanhee Jang ◽

Hanseul Oh ◽

...

Keyword(s):

T Cell ◽

Nonhuman Primates ◽

Vaccine Candidate ◽

T Cell Responses ◽

Neutralizing Antibody ◽

Dependent Manner ◽

Viral Loads ◽

Cell Responses ◽

Rapid Spread

The unprecedented and rapid spread of SARS-CoV-2 (severe acute respiratory syndrome-coronavirus-2) has motivated the need for a rapidly producible and scalable vaccine. Here, we developed a synthetic soluble SARS-CoV-2 spike (S) DNA-based vaccine candidate, GX-19. In mice, immunization with GX-19 elicited not only S-specific systemic and pulmonary antibody responses but also Th1-biased T cell responses in a dose-dependent manner. GX-19-vaccinated nonhuman primates seroconverted rapidly and exhibited a detectable neutralizing antibody response as well as multifunctional CD4+ and CD8+ T cell responses. Notably, when the immunized nonhuman primates were challenged at 10 weeks after the last vaccination with GX-19, they had reduced viral loads in contrast to non-vaccinated primates as a control. These findings indicate that GX-19 vaccination provides a durable protective immune response and also support further development of GX-19 as a vaccine candidate for SARS-CoV-2.

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Modified Vaccinia Ankara Based SARS-CoV-2 Vaccine Expressing Full-Length Spike Induces Strong Neutralizing Antibody Response

10.1101/2020.06.27.175166 ◽

2020 ◽

Cited By ~ 1

Author(s):

Nanda Kishore Routhu ◽

Sailaja Gangadhara ◽

Narayanaiah Cheedarla ◽

Ayalnesh Shiferaw ◽

Sheikh Abdul Rahman ◽

...

Keyword(s):

Antibody Response ◽

Room Temperature ◽

Vaccine Candidate ◽

Neutralizing Antibody ◽

Antibody Responses ◽

Full Length ◽

Spike Protein ◽

Strongly Correlated ◽

Igg Antibodies ◽

Potential Vaccine

AbstractThere is a great need for the development of vaccines for preventing SARS-CoV-2 infection and mitigating the COVID-19 pandemic. Here, we developed two modified vaccinia Ankara (MVA) based vaccines which express either a membrane anchored full-length spike protein (MVA/S) stabilized in a prefusion state or the S1 region of the spike (MVA/S1) which forms trimers and is secreted. Both immunogens contained the receptor-binding domain (RBD) which is a known target of antibody-mediated neutralization. Following immunizations with MVA/S or MVA/S1, both spike protein recombinants induced strong IgG antibodies to purified full-length SARS-CoV-2 spike protein. The MVA/S induced a robust antibody response to purified RBD, S1 and S2 whereas MVA/S1 induced an antibody response to the S1 region outside of the RBD region. Both vaccines induced an antibody response in the lung and that was associated with induction of bronchus-associated lymphoid tissue. MVA/S but not MVA/S1 vaccinated mice generated robust neutralizing antibody responses against SARS-CoV-2 that strongly correlated with RBD antibody binding titers. Mechanistically, S1 binding to ACE-2 was strong but reduced following prolonged pre-incubation at room temperature suggesting confirmation changes in RBD with time. These results demonstrate MVA/S is a potential vaccine candidate against SARS-CoV-2 infection.

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Soluble Spike DNA vaccine provides long-term protective immunity against SAR-CoV-2 in mice and nonhuman primates

10.1101/2020.10.09.334136 ◽

2020 ◽

Author(s):

Yong Bok Seo ◽

You Suk Suh ◽

Ji In Ryu ◽

Hwanhee Jang ◽

Hanseul Oh ◽

...

Keyword(s):

T Cell ◽

Nonhuman Primates ◽

Vaccine Candidate ◽

T Cell Responses ◽

Neutralizing Antibody ◽

Dependent Manner ◽

Viral Loads ◽

Cell Responses ◽

Rapid Spread

SummaryThe unprecedented and rapid spread of SARS-CoV-2 has motivated the need for a rapidly producible and scalable vaccine. Here, we developed a synthetic soluble SARS-CoV-2 spike (S) DNA-based vaccine candidate, GX-19. In mice, immunization with GX-19 elicited not only S-specific systemic and pulmonary antibody responses but also Th1-biased T cell responses in a dose-dependent manner. GX-19 vaccinated nonhuman primate seroconverted rapidly and exhibited detectable neutralizing antibody response as well as multifunctional CD4+ and CD8+ T cell responses. Notably, when the immunized nonhuman primates were challenged at 10 weeks after the last vaccination with GX-19, they did not develop fever and reduced viral loads in contrast to non-vaccinated primates as a control. These findings indicate that GX-19 vaccination provides durable protective immune response and also support further development of GX-19 as a vaccine candidate for SARS-CoV-2 in human clinical trials.

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RBD-Fc-based COVID-19 vaccine candidate induces highly potent SARS-CoV-2 neutralizing antibody response

Signal Transduction and Targeted Therapy ◽

10.1038/s41392-020-00402-5 ◽

2020 ◽

Vol 5 (1) ◽

Author(s):

Zezhong Liu ◽

Wei Xu ◽

Shuai Xia ◽

Chenjian Gu ◽

Xinling Wang ◽

...

Keyword(s):

Subunit Vaccine ◽

Vaccine Candidate ◽

High Titer ◽

Neutralizing Antibody ◽

Spike Protein ◽

Receptor Binding Domain ◽

Angiotensin Converting Enzyme 2 ◽

Specific Antibodies ◽

Good Potential ◽

Neutralizing Epitopes

AbstractThe pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has posed serious threats to global health and economy, thus calling for the development of safe and effective vaccines. The receptor-binding domain (RBD) in the spike protein of SARS-CoV-2 is responsible for its binding to angiotensin-converting enzyme 2 (ACE2) receptor. It contains multiple dominant neutralizing epitopes and serves as an important antigen for the development of COVID-19 vaccines. Here, we showed that immunization of mice with a candidate subunit vaccine consisting of SARS-CoV-2 RBD and Fc fragment of human IgG, as an immunopotentiator, elicited high titer of RBD-specific antibodies with robust neutralizing activity against both pseudotyped and live SARS-CoV-2 infections. The mouse antisera could also effectively neutralize infection by pseudotyped SARS-CoV-2 with several natural mutations in RBD and the IgG extracted from the mouse antisera could also show neutralization against pseudotyped SARS-CoV and SARS-related coronavirus (SARSr-CoV). Vaccination of human ACE2 transgenic mice with RBD-Fc could effectively protect mice from the SARS-CoV-2 challenge. These results suggest that SARS-CoV-2 RBD-Fc has good potential to be further developed as an effective and broad-spectrum vaccine to prevent infection of the current SARS-CoV-2 and its mutants, as well as future emerging SARSr-CoVs and re-emerging SARS-CoV.

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Simulation of the Clinical and Pathological Manifestations of Coronavirus Disease 2019 (COVID-19) in a Golden Syrian Hamster Model: Implications for Disease Pathogenesis and Transmissibility

Clinical Infectious Diseases ◽

10.1093/cid/ciaa325 ◽

2020 ◽

Cited By ~ 166

Author(s):

Jasper Fuk-Woo Chan ◽

Anna Jinxia Zhang ◽

Shuofeng Yuan ◽

Vincent Kwok-Man Poon ◽

Chris Chung-Sing Chan ◽

...

Keyword(s):

Weight Loss ◽

Viral Load ◽

Syrian Hamster ◽

Clinical Signs ◽

Neutralizing Antibody ◽

Adaptive Mutation ◽

Lung Pathology ◽

Hamster Model ◽

Golden Syrian Hamster ◽

Virus Challenge

Abstract Background A physiological small-animal model that resembles COVID-19 with low mortality is lacking. Methods Molecular docking on the binding between angiotensin-converting enzyme 2 (ACE2) of common laboratory mammals and the receptor-binding domain of the surface spike protein of SARS-CoV-2 suggested that the golden Syrian hamster is an option. Virus challenge, contact transmission, and passive immunoprophylaxis studies were performed. Serial organ tissues and blood were harvested for histopathology, viral load and titer, chemokine/cytokine level, and neutralizing antibody titer. Results The Syrian hamster could be consistently infected by SARS-CoV-2. Maximal clinical signs of rapid breathing, weight loss, histopathological changes from the initial exudative phase of diffuse alveolar damage with extensive apoptosis to the later proliferative phase of tissue repair, airway and intestinal involvement with viral nucleocapsid protein expression, high lung viral load, and spleen and lymphoid atrophy associated with marked chemokine/cytokine activation were observed within the first week of virus challenge. The mean lung virus titer was between 105 and 107 TCID50/g. Challenged index hamsters consistently infected naive contact hamsters housed within the same cages, resulting in similar pathology but not weight loss. All infected hamsters recovered and developed mean serum neutralizing antibody titers ≥1:427 14 days postchallenge. Immunoprophylaxis with early convalescent serum achieved significant decrease in lung viral load but not in lung pathology. No consistent nonsynonymous adaptive mutation of the spike was found in viruses isolated from the infected hamsters. Conclusions Besides satisfying Koch’s postulates, this readily available hamster model is an important tool for studying transmission, pathogenesis, treatment, and vaccination against SARS-CoV-2.

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BCX4430, a Novel Nucleoside Analog, Effectively Treats Yellow Fever in a Hamster Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.03368-14 ◽

2014 ◽

Vol 58 (11) ◽

pp. 6607-6614 ◽

Cited By ~ 44

Author(s):

Justin G. Julander ◽

Shanta Bantia ◽

Brian R. Taubenheim ◽

Dena M. Minning ◽

Pravin Kotian ◽

...

Keyword(s):

Weight Loss ◽

Yellow Fever ◽

Yellow Fever Virus ◽

Neutralizing Antibody ◽

Therapeutic Index ◽

Nucleoside Analog ◽

Hamster Model ◽

Virus Challenge ◽

Highly Active ◽

Improvement In Survival

ABSTRACTNo effective antiviral therapies are currently available to treat disease after infection with yellow fever virus (YFV). A Syrian golden hamster model of yellow fever (YF) was used to characterize the effect of treatment with BCX4430, a novel adenosine nucleoside analog. Significant improvement in survival was observed after treatment with BCX4430 at 4 mg/kg of body weight per day dosed intraperitoneally (i.p.) twice daily (BID). Treatment with BCX4430 at 12.5 mg/kg/day administered i.p. BID for 7 days offered complete protection from mortality and also resulted in significant improvement of other YF disease parameters, including weight loss, serum alanine aminotransferase levels (6 days postinfection [dpi]), and viremia (4 dpi). In uninfected hamsters, BCX4430 at 200 mg/kg/day administered i.p. BID for 7 days was well tolerated and did not result in mortality or weight loss, suggesting a potentially wide therapeutic index. Treatment with BCX4430 at 12 mg/kg/day i.p. remained effective when administered once daily and for only 4 days. Moreover, BCX4430 dosed at 200 mg/kg/day i.p. BID for 7 days effectively treated YF, even when treatment was delayed up to 4 days after virus challenge, corresponding with peak viral titers in the liver and serum. BCX4430 treatment did not preclude a protective antibody response, as higher neutralizing antibody (nAb) concentrations corresponded with increasing delays of treatment initiation, and greater nAb responses resulted in the protection of animals from a secondary challenge with YFV. In summary, BCX4430 is highly active in a hamster model of YF, even when treatment is initiated at the peak of viral replication.

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BANCOVID, the first D614G variant mRNA-based vaccine candidate against SARS-CoV-2 elicits neutralizing antibody and balanced cellular immune response

10.1101/2020.09.29.319061 ◽

2020 ◽

Author(s):

Juwel Chandra Baray ◽

Md. Maksudur Rahman Khan ◽

Asif Mahmud ◽

Md. Jikrul Islam ◽

Sanat Myti ◽

...

Keyword(s):

Vaccine Development ◽

Vaccine Candidate ◽

Neutralizing Antibody ◽

Spike Protein ◽

Hek293 Cells ◽

Effective Vaccine ◽

Great Promise ◽

Dependent Manner ◽

Preclinical Trial ◽

Almost All

AbstractEffective vaccine against SARS-CoV-2 is the utmost importance in the current world. More than 1 million deaths are accounted for relevant pandemic disease COVID-19. Recent data showed that D614G genotype of the virus is highly infectious and responsible for almost all infection for 2nd wave. Despite of multiple vaccine development initiatives, there are currently no report that has addressed this critical variant D614G as vaccine candidate. Here we report the development of an mRNA-LNP vaccine considering the D614G variant and characterization of the vaccine in preclinical trial. The surface plasmon resonance (SPR) data with spike protein as probe and competitive neutralization with RBD and S2 domain revealed that immunization generated specific antibody pools against the whole extracellular domain (RBD and S2) of the spike protein. The anti-sera and purified IgGs from immunized mice on day 7 and 14 neutralized SARS-CoV-2 pseudovirus in ACE2-expressing HEK293 cells in a dose dependent manner. Importantly, immunization protected mice lungs from pseudovirus entry and cytopathy. The immunologic responses have been implicated by a balanced and stable population of CD4+ cells with a Th1 bias. The IgG2a to IgG1 and (IgG2a+IgG2b) to (IgG1+IgG3) ratios were found 1±0.2 and 1.24±0.1, respectively. These values are comparatively higher than relevant values for other published SARS-CoV-2 vaccine in development,1, 2 and suggesting higher viral clearance capacity for our vaccine. The data suggested great promise for immediate translation of the technology to the clinic.

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Replicating bacterium-vectored vaccine expressing SARS-CoV-2 Membrane and Nucleocapsid proteins protects against severe COVID-19-like disease in hamsters

npj Vaccines ◽

10.1038/s41541-021-00321-8 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Qingmei Jia ◽

Helle Bielefeldt-Ohmann ◽

Rachel M. Maison ◽

Saša Masleša-Galić ◽

Sarah K. Cooper ◽

...

Keyword(s):

Weight Loss ◽

Structural Proteins ◽

High Dose ◽

Lung Pathology ◽

High Homology ◽

Universal Vaccine ◽

Nucleocapsid Proteins ◽

Syrian Hamsters ◽

Viral Loads ◽

Vectored Vaccine

AbstractTo generate an inexpensive readily manufactured COVID-19 vaccine, we employed the LVS ΔcapB vector platform, previously used to generate potent candidate vaccines against Select Agent diseases tularemia, anthrax, plague, and melioidosis. Vaccines expressing SARS-CoV-2 structural proteins are constructed using the LVS ΔcapB vector, a highly attenuated replicating intracellular bacterium, and evaluated for efficacy in golden Syrian hamsters, which develop severe COVID-19-like disease. Hamsters immunized intradermally or intranasally with a vaccine co-expressing the Membrane and Nucleocapsid proteins and challenged 5 weeks later with a high dose of SARS-CoV-2 are protected against severe weight loss and lung pathology and show reduced viral loads in the oropharynx and lungs. Protection correlates with anti-Nucleocapsid antibody. This potent vaccine should be safe; inexpensive; easily manufactured, stored, and distributed; and given the high homology between Membrane and Nucleocapsid proteins of SARS-CoV and SARS-CoV-2, potentially serve as a universal vaccine against the SARS subset of pandemic causing β-coronaviruses.

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A single dose of replication-competent VSV-vectored vaccine expressing SARS-CoV-2 S1 protects against virus replication in a hamster model of severe COVID-19

npj Vaccines ◽

10.1038/s41541-021-00352-1 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Delphine C. Malherbe ◽

Drishya Kurup ◽

Christoph Wirblich ◽

Adam J. Ronk ◽

Chad Mire ◽

...

Keyword(s):

Weight Loss ◽

Vesicular Stomatitis Virus ◽

Neutralizing Antibodies ◽

Specific Binding ◽

Vaccine Dose ◽

Spike Protein ◽

Hamster Model ◽

Rapid Control ◽

Vesicular Stomatitis ◽

Vectored Vaccine

AbstractThe development of effective countermeasures against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the agent responsible for the COVID-19 pandemic, is a priority. We designed and produced ConVac, a replication-competent vesicular stomatitis virus (VSV) vaccine vector that expresses the S1 subunit of SARS-CoV-2 spike protein. We used golden Syrian hamsters as animal models of severe COVID-19 to test the efficacy of the ConVac vaccine. A single vaccine dose elicited high levels of SARS-CoV-2 specific binding and neutralizing antibodies; following intranasal challenge with SARS-CoV-2, animals were protected from weight loss and viral replication in the lungs. No enhanced pathology was observed in vaccinated animals upon challenge, but some inflammation was still detected. The data indicate rapid control of SARS-CoV-2 replication by the S1-based VSV-vectored SARS-CoV-2 ConVac vaccine.

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