scholarly journals Adaptation of SARS-CoV-2 in BALB/c mice for testing vaccine efficacy

Science ◽  
2020 ◽  
pp. eabc4730 ◽  
Author(s):  
Hongjing Gu ◽  
Qi Chen ◽  
Guan Yang ◽  
Lei He ◽  
Hang Fan ◽  
...  
Keyword(s):  
Vaccine Candidate ◽  
Inflammatory Responses ◽  
Protective Efficacy ◽  
Small Animal ◽  
Spike Protein ◽  
Mouse Lung ◽  
Receptor Binding Domain ◽  
Intranasal Inoculation ◽  
Adaptive Mutations ◽  
Small Animal Models

The ongoing COVID-19 pandemic has prioritized the development of small animal models for SARS-CoV-2. Herein, we adapted a clinical isolate of SARS-CoV-2 by serial passaging in the respiratory tract of aged BALB/c mice. The resulting mouse-adapted strain at passage 6 (termed MASCp6) showed increased infectivity in mouse lung, and led to interstitial pneumonia and inflammatory responses in both young and aged mice following intranasal inoculation. Deep sequencing revealed a panel of adaptive mutations potentially associated with the increased virulence. In particular, the N501Y mutation is located at the receptor binding domain (RBD) of the spike protein. The protective efficacy of a recombinant RBD vaccine candidate was validated using this model. Thus, this mouse-adapted strain and associated challenge model should be of value in evaluating vaccines and antivirals against SARS-CoV-2.

scholarly journals Antibody Resistance of SARS-CoV-2 Variants B.1.351 and B.1.1.7

2021 ◽  
Author(s):  
Pengfei Wang ◽  
Manoj S. Nair ◽  
Lihong Liu ◽  
Sho Iketani ◽  
Yang Luo ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Protective Efficacy ◽  
Spike Protein ◽  
Binding Motif ◽  
Receptor Binding Domain ◽  
Effective Interventions ◽  
Recent Emergence ◽  
New Challenges ◽  
The Uk ◽  
Antibody Resistance

The COVID-19 pandemic has ravaged the globe, and its causative agent, SARS-CoV-2, continues to rage. Prospects of ending this pandemic rest on the development of effective interventions. Single and combination monoclonal antibody (mAb) therapeutics have received emergency use authorization1–3, with more in the pipeline4–7. Furthermore, multiple vaccine constructs have shown promise8, including two with ~95% protective efficacy against COVID-199,10. However, these interventions were directed toward the initial SARS-CoV-2 that emerged in 2019. The recent emergence of new SARS-CoV-2 variants B.1.1.7 in the UK11 and B.1.351 in South Africa12 is of concern because of their purported ease of transmission and extensive mutations in the spike protein. We now report that B.1.1.7 is refractory to neutralization by most mAbs to the N-terminal domain (NTD) of spike and relatively resistant to a few mAbs to the receptor-binding domain (RBD). It is not more resistant to convalescent plasma or vaccinee sera. Findings on B.1.351 are more worrisome in that this variant is not only refractory to neutralization by most NTD mAbs but also by multiple individual mAbs to the receptor-binding motif on RBD, largely due to an E484K mutation. Moreover, B.1.351 is markedly more resistant to neutralization by convalescent plasma (9.4 fold) and vaccinee sera (10.3-12.4 fold). B.1.351 and emergent variants13,14 with similar spike mutations present new challenges for mAb therapy and threaten the protective efficacy of current vaccines.

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

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.

scholarly journals Potent Neutralization Antibodies Induced by a Recombinant Trimeric Spike Protein Vaccine Candidate Containing PIKA Adjuvant for COVID-19

Vaccines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 296
Author(s):  
Jiao Tong ◽  
Chenxi Zhu ◽  
Hanyu Lai ◽  
Chunchao Feng ◽  
Dapeng Zhou
Keyword(s):  
Monoclonal Antibodies ◽  
Vaccine Candidate ◽  
Spike Protein ◽  
Heptad Repeat ◽  
Peptide Array ◽  
Receptor Binding Domain ◽  
Protein Vaccine ◽  
Direct Binding ◽  
Linear Epitopes ◽  
Potent Neutralization

The structures of immunogens that elicit the most potent neutralization antibodies to prevent COVID-19 infection are still under investigation. In this study, we tested the efficacy of a recombinant trimeric Spike protein containing polyI:C (PIKA) adjuvant in mice immunized by a 0–7–14 day schedule. The results showed that a Spike protein-specific antibody was induced at Day 21 with titer of above 50,000 on average, as measured by direct binding. The neutralizing titer was above 1000 on average, as determined by a pseudo-virus using monoclonal antibodies (40592-MM57 and 40591-MM43) with IC50 at 1 μg/mL as standards. The protein/peptide array-identified receptor-binding domain (RBD) was considered as immunodominant. No linear epitopes were found in the RBD, although several linear epitopes were found in the C-terminal domain right after the RBD and heptad repeat regions. Our study supports the efficacy of a recombinant trimeric Spike protein vaccine candidate for COVID-19 that is safe and ready for storage and distribution in developing countries.

scholarly journals Optimization of an LNP-mRNA vaccine candidate targeting SARS-CoV-2 receptor-binding domain

2021 ◽  
Author(s):  
Kouji Kobiyama ◽  
Masaki Imai ◽  
Nao Jounai ◽  
Misako Nakayama ◽  
Kou Hioki ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Receptor Binding ◽  
Vaccine Candidate ◽  
Type I Interferon ◽  
Binding Domain ◽  
Spike Protein ◽  
Type I ◽  
Vaccine Formulation ◽  
Receptor Binding Domain ◽  
Cynomolgus Macaques

In 2020, two mRNA-based vaccines, encoding the full length of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein, have been introduced for control of the coronavirus disease (COVID-19) pandemic1,2. However, reactogenicity, such as fever, caused by innate immune responses to the vaccine formulation remains to be improved. Here, we optimized a lipid nanoparticle (LNP)-based mRNA vaccine candidate, encoding the SARS-CoV-2 spike protein receptor-binding domain (LNP-mRNA-RBD), which showed improved immunogenicity by removing reactogenic materials from the vaccine formulation and protective potential against SARS-CoV-2 infection in cynomolgus macaques. LNP-mRNA-RBD induced robust antigen-specific B cells and follicular helper T cells in the BALB/c strain but not in the C57BL/6 strain; the two strains have contrasting abilities to induce type I interferon production by dendritic cells. Removal of reactogenic materials from original synthesized mRNA by HPLC reduced type I interferon (IFN) production by dendritic cells, which improved immunogenicity. Immunization of cynomolgus macaques with an LNP encapsulating HPLC-purified mRNA induced robust anti-RBD IgG in the plasma and in various mucosal areas, including airways, thereby conferring protection against SARS-CoV-2 infection. Therefore, fine-tuning the balance between the immunogenic and reactogenic activity of mRNA-based vaccine formulations may offer safer and more efficacious outcomes.

scholarly journals Comparative Immunomodulatory Evaluation of the Receptor Binding Domain of the SARS-CoV-2 Spike Protein; a Potential Vaccine Candidate Which Imparts Potent Humoral and Th1 Type Immune Response in a Mouse Model

2021 ◽  
Vol 12 ◽  
Author(s):  
Tripti Shrivastava ◽  
Balwant Singh ◽  
Zaigham Abbas Rizvi ◽  
Rohit Verma ◽  
Sandeep Goswami ◽  
...  
Keyword(s):  
Immune Response ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Vaccine Candidate ◽  
Unmet Need ◽  
Binding Domain ◽  
Spike Protein ◽  
Cell Immune Response ◽  
Receptor Binding Domain

The newly emerged novel coronavirus, SARS-CoV-2, the causative agent of COVID-19 has proven to be a threat to the human race globally, thus, vaccine development against SARS-CoV-2 is an unmet need driving mass vaccination efforts. The receptor binding domain of the spike protein of this coronavirus has multiple neutralizing epitopes and is associated with viral entry. Here we have designed and characterized the SARS-CoV-2 spike protein fragment 330-526 as receptor binding domain 330-526 (RBD330-526) with two native glycosylation sites (N331 and N343); as a potential subunit vaccine candidate. We initially characterized RBD330-526 biochemically and investigated its thermal stability, humoral and T cell immune response of various RBD protein formulations (with or without adjuvant) to evaluate the inherent immunogenicity and immunomodulatory effect. Our result showed that the purified RBD immunogen is stable up to 72 h, without any apparent loss in affinity or specificity of interaction with the ACE2 receptor. Upon immunization in mice, RBD generates a high titer humoral response, elevated IFN-γ producing CD4+ cells, cytotoxic T cells, and robust neutralizing antibodies against live SARS-CoV-2 virus. Our results collectively support the potential of RBD330-526 as a promising vaccine candidate against SARS-CoV-2.

scholarly journals Development of a COVID-19 vaccine based on the receptor binding domain displayed on virus-like particles

2020 ◽  
Author(s):  
Lisha Zha ◽  
Hongxin Zhao ◽  
Mona O. Mohsen ◽  
Liang Hong ◽  
Yuhang Zhou ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Vaccine Candidate ◽  
Rapid Development ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Viral Receptor ◽  
Virus Like Particles ◽  
The City

AbstractThe recently ermerging disease COVID-19 is caused by the new SARS-CoV-2 virus first detected in the city of Wuhan, China. From there it has been rapidly spreading inside and outside China. With initial death rates around 4%, COVID-19 patients at longer distances from Wuhan showed reduced mortality as was previously observed for the SARS coronavirus. However, the new coronavirus spreads more strongly, as it sheds long before onset of symptoms or may be transmitted by people without symptoms. Rapid development of a protective vaccine against COVID-19 is therefore of paramount importance. Here we demonstrate that recombinantly expressed receptor binding domain (RBD) of the spike protein homologous to SARS binds to ACE2, the viral receptor. Higly repetitive display of RBD on immunologically optimized virus-like particles derived from cucumber mosaic virus resulted in a vaccine candidate (RBD-CuMVTT) that induced high levels of specific antibodies in mice which were able to block binding of spike protein to ACE2 and potently neutralized the SARS-CoV-2 virus in vitro.

scholarly journals Next generation live-attenuated yellow fever vaccine candidate: Safety and immuno-efficacy in small animal models

Vaccine ◽  
2021 ◽  
Author(s):  
Fabienne Piras-Douce ◽  
Franck Raynal ◽  
Alix Raquin ◽  
Yves Girerd-Chambaz ◽  
Sylviane Gautheron ◽  
...  
Keyword(s):  
Animal Models ◽  
Yellow Fever ◽  
Vaccine Candidate ◽  
Small Animal ◽  
Yellow Fever Vaccine ◽  
Next Generation ◽  
Small Animal Models

scholarly journals Receptor-binding domain of SARS-CoV-2 spike protein efficiently inhibits SARS-CoV-2 infection and attachment to mouse lung

2021 ◽  
Vol 17 (14) ◽  
pp. 3786-3794
Author(s):  
Hye Jin Shin ◽  
Keun Bon Ku ◽  
Hae Soo Kim ◽  
Hyun Woo Moon ◽  
Gi Uk Jeong ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Binding Domain ◽  
Spike Protein ◽  
Mouse Lung ◽  
Receptor Binding Domain

scholarly journals Increased Resistance of SARS-CoV-2 Variants B.1.351 and B.1.1.7 to Antibody Neutralization

2021 ◽  
Author(s):  
David Ho ◽  
Pengfei Wang ◽  
Lihong Liu ◽  
Sho Iketani ◽  
Yang Luo ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Protective Efficacy ◽  
Viral Evolution ◽  
Spike Protein ◽  
Binding Motif ◽  
Receptor Binding Domain ◽  
Effective Interventions ◽  
Recent Emergence ◽  
New Challenges ◽  
The Uk

Abstract The Covid-19 pandemic has ravaged the globe, and its causative agent, SARS-CoV-2, continues to rage. Prospects of ending this pandemic rest on the development of effective interventions. Two monoclonal antibody (mAb) therapeutics have received emergency use authorization, and more are in the pipeline. Furthermore, multiple vaccine constructs have shown promise, including two with ~95% protective efficacy against Covid-19. However, these interventions were directed toward the initial SARS-CoV-2 that emerged in 2019. Considerable viral evolution has occurred since, including variants with a D614G mutation that have become dominant. Viruses with this mutation alone do not appear to be antigenically distinct, however. Recent emergence of new SARS-CoV-2 variants B.1.1.7 in the UK and B.1.351 in South Africa is of concern because of their purported ease of transmission and extensive mutations in the spike protein. We now report that B.1.1.7 is refractory to neutralization by most mAbs to the N-terminal domain (NTD) of spike and relatively resistant to a number of mAbs to the receptor-binding domain (RBD). It is modestly more resistant to convalescent plasma (~3 fold) and vaccinee sera (~2 fold). Findings on B.1.351 are more worrisome in that this variant is not only refractory to neutralization by most NTD mAbs but also by multiple potent mAbs to the receptor-binding motif on RBD, largely due to an E484K mutation. Moreover, B.1.351 is markedly more resistant to neutralization by convalescent plasma (~11-33 fold) and vaccinee sera (~6.5-8.6 fold). B.1.351 and emergent variants with similar spike mutations present new challenges for mAb therapy and threaten the protective efficacy of current vaccines.

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