scholarly journals A single immunization with a rhabdovirus-based vector expressing severe acute respiratory syndrome coronavirus (SARS-CoV) S protein results in the production of high levels of SARS-CoV-neutralizing antibodies

2005 ◽  
Vol 86 (5) ◽  
pp. 1435-1440 ◽  
Author(s):  
Milosz Faber ◽  
Elaine W. Lamirande ◽  
Anjeanette Roberts ◽  
Amy B. Rice ◽  
Hilary Koprowski ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Protein S ◽  
S Protein ◽  
Cellular Immune Responses ◽  
Glycoprotein G ◽  
Cellular Immune ◽  
Animal Reservoirs ◽  
S Genes

Foreign viral proteins expressed by rabies virus (RV) have been shown to induce potent humoral and cellular immune responses in immunized animals. In addition, highly attenuated and, therefore, very safe RV-based vectors have been constructed. Here, an RV-based vaccine vehicle was utilized as a novel vaccine against severe acute respiratory syndrome coronavirus (SARS-CoV). For this approach, the SARS-CoV nucleocapsid protein (N) or envelope spike protein (S) genes were cloned between the RV glycoprotein G and polymerase L genes. Recombinant vectors expressing SARS-CoV N or S protein were recovered and their immunogenicity was studied in mice. A single inoculation with the RV-based vaccine expressing SARS-CoV S protein induced a strong SARS-CoV-neutralizing antibody response. The ability of the RV-SARS-CoV S vector to confer immunity after a single inoculation makes this live vaccine a promising candidate for eradication of SARS-CoV in animal reservoirs, thereby reducing the risk of transmitting the infection to humans.

scholarly journals Comparative evaluation of two severe acute respiratory syndrome (SARS) vaccine candidates in mice challenged with SARS coronavirus

2006 ◽  
Vol 87 (3) ◽  
pp. 641-650 ◽  
Author(s):  
Raymond H. See ◽  
Alexander N. Zakhartchouk ◽  
Martin Petric ◽  
David J. Lawrence ◽  
Catherine P. Y. Mok ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Immune Responses ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
High Serum ◽  
Sars Coronavirus ◽  
Mouse Splenocytes ◽  
Cellular Immune Responses ◽  
Antibody Titres ◽  
Cellular Immune

Two different severe acute respiratory syndrome (SARS) vaccine strategies were evaluated for their ability to protect against live SARS coronavirus (CoV) challenge in a murine model of infection. A whole killed (inactivated by β-propiolactone) SARS-CoV vaccine and a combination of two adenovirus-based vectors, one expressing the nucleocapsid (N) and the other expressing the spike (S) protein (collectively designated Ad S/N), were evaluated for the induction of serum neutralizing antibodies and cellular immune responses and their ability to protect against pulmonary SARS-CoV replication. The whole killed virus (WKV) vaccine given subcutaneously to 129S6/SvEv mice was more effective than the Ad S/N vaccine administered either intranasally or intramuscularly in inhibiting SARS-CoV replication in the murine respiratory tract. This protective ability of the WKV vaccine correlated with the induction of high serum neutralizing-antibody titres, but not with cellular immune responses as measured by gamma interferon secretion by mouse splenocytes. Titres of serum neutralizing antibodies induced by the Ad S/N vaccine administered intranasally or intramuscularly were significantly lower than those induced by the WKV vaccine. However, Ad S/N administered intranasally, but not intramuscularly, significantly limited SARS-CoV replication in the lungs. Among the vaccine groups, SARS-CoV-specific IgA was found only in the sera of mice immunized intranasally with Ad S/N, suggesting that mucosal immunity may play a role in protection for the intranasal Ad S/N delivery system. Finally, the sera of vaccinated mice contained antibodies to S, further suggesting a role for this protein in conferring protective immunity against SARS-CoV infection.

scholarly journals Control of SARS-CoV-2 infection after Spike DNA or Spike DNA+Protein co-immunization in rhesus macaques

2021 ◽  
Author(s):  
Margherita Rosati ◽  
Mahesh Agarwal ◽  
Xintao Hu ◽  
Santhi Devasundaram ◽  
Dimitris Stellas ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Protective Efficacy ◽  
Rhesus Macaques ◽  
Neutralizing Antibody ◽  
Anatomical Site ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Antibody Titers ◽  
Cellular Immune

The speed of development, versatility and efficacy of mRNA-based vaccines have been amply demonstrated in the case of SARS-CoV-2. DNA vaccines represent an important alternative since they induce both humoral and cellular immune responses in animal models and in human trials. We tested the immunogenicity and protective efficacy of DNA-based vaccine regimens expressing different prefusion-stabilized SARS-CoV-2 Spike antigens upon intramuscular injection followed by electroporation in rhesus macaques. Different Spike DNA vaccine regimens induced antibodies that potently neutralized SARS-CoV-2 in vitro and elicited robust T cell responses. The DNA-only vaccine regimens were compared to a regimen that included co-immunization of Spike DNA and protein in the same anatomical site, the latter of which showed significant higher antibody responses. All vaccine regimens led to control of SARS-CoV-2 intranasal/intratracheal challenge and absence of virus dissemination to the lower respiratory tract. Vaccine-induced binding and neutralizing antibody titers and antibody-dependent cellular phagocytosis inversely correlated with transient virus levels in the nasal mucosa. Importantly, the Spike DNA+Protein co-immunization regimen induced the highest binding and neutralizing antibodies and showed the strongest control against SARS-CoV-2 challenge in rhesus macaques.

scholarly journals SARS-CoV-2 spike protein arrested in the closed state induces potent neutralizing responses

2021 ◽  
Author(s):  
George W. Carnell ◽  
Katarzyna A. Ciazynska ◽  
David A. Wells ◽  
Xiaoli Xiong ◽  
Ernest T. Aguinam ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Protein S ◽  
Spike Protein ◽  
Receptor Binding Site ◽  
S Protein ◽  
Closed State ◽  
S Proteins ◽  
Protein Constructs

AbstractThe majority of SARS-CoV-2 vaccines in use or in advanced clinical development are based on the viral spike protein (S) as their immunogen. S is present on virions as pre-fusion trimers in which the receptor binding domain (RBD) is stochastically open or closed. Neutralizing antibodies have been described that act against both open and closed conformations. The long-term success of vaccination strategies will depend upon inducing antibodies that provide long-lasting broad immunity against evolving, circulating SARS-CoV-2 strains, while avoiding the risk of antibody dependent enhancement as observed with other Coronavirus vaccines. Here we have assessed the results of immunization in a mouse model using an S protein trimer that is arrested in the closed state to prevent exposure of the receptor binding site and therefore interaction with the receptor. We compared this with a range of other modified S protein constructs, including representatives used in current vaccines. We found that all trimeric S proteins induce a long-lived, strongly neutralizing antibody response as well as T-cell responses. Notably, the protein binding properties of sera induced by the closed spike differed from those induced by standard S protein constructs. Closed S proteins induced more potent neutralising responses than expected based on the degree to which they inhibit interactions between the RBD and ACE2. These observations suggest that closed spikes recruit different, but equally potent, virus-inhibiting immune responses than open spikes, and that this is likely to include neutralizing antibodies against conformational epitopes present in the closed conformation. Together with their improved stability and storage properties we suggest that closed spikes may be a valuable component of refined, next-generation vaccines.

scholarly journals Immunogenicity of low dose prime-boost vaccination of mRNA vaccine CV07050101 in non-human primates

2021 ◽  
Author(s):  
Neeltje van Doremalen ◽  
Robert Fischer ◽  
Jonathan Schulz ◽  
Myndi Holbrook ◽  
Brian Smith ◽  
...  
Keyword(s):  
Immune Responses ◽  
Neutralizing Antibodies ◽  
Vaccine Candidate ◽  
Small Animal ◽  
S Protein ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Boost Vaccination ◽  
Human Volunteers ◽  
Cellular Immune

Many different vaccine candidates against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the etiological agent of COVID-19, are currently approved and under development. Vaccine platforms vary from mRNA vaccines to viral-vectored vaccines, and several candidates have been shown to produce humoral and cellular responses in small animal models, non-human primates and human volunteers. In this study, six non-human primates received a prime-boost intramuscular vaccination with 4 μg of mRNA vaccine candidate CV07050101, which encodes a pre-fusion stabilized spike (S) protein of SARS-CoV-2. Boost vaccination was performed 28 days post prime vaccination. As a control, six animals were similarly injected with PBS. Humoral and cellular immune responses were investigated at time of vaccination, and two weeks afterwards. No antibodies could be detected two and four weeks after prime vaccination. Two weeks after boost vaccination, binding but no neutralizing antibodies were detected in 4 out of 6 non-human primates. SARS-CoV-2 S protein specific T cell responses were detected in these 4 animals. In conclusion, prime-boost vaccination with 4 μg of vaccine candidate CV07050101 resulted in limited immune responses in 4 out of 6 non-human primates.

scholarly journals Effects of Spike Mutations in SARS-CoV-2 Variants of Concern on Human or Animal ACE2-Mediated Virus Entry and Neutralization

2021 ◽  
Author(s):  
Yunjeong Kim ◽  
Natasha N Gaudreault ◽  
David A Meekins ◽  
Krishani D Perera ◽  
Dashzeveg Bold ◽  
...  
Keyword(s):  
Viral Entry ◽  
Neutralizing Antibodies ◽  
Animal Species ◽  
Virus Entry ◽  
Neutralizing Antibody ◽  
Protein S ◽  
Pseudotyped Virus ◽  
S Protein ◽  
Viral Neutralization ◽  
Wide Range

SARS-CoV-2 is a zoonotic agent capable of infecting humans and a wide range of animal species. Over the duration of the pandemic, mutations in the SARS-CoV-2 Spike protein (S) have arisen in circulating viral populations, culminating in the spread of several variants of concern (VOC) with varying degrees of altered virulence, transmissibility, and neutralizing antibody escape. In this study, we employed lentivirus-based pseudotyped viruses that express specific SARS-CoV-2 S protein substitutions and cell lines that stably express ACE2 from nine different animal species to gain insights into the effects of VOC mutations on viral entry and antibody neutralization capability. All animal ACE2 receptors tested, except mink, support viral cell entry for pseudoviruses expressing the parental (prototype Wuhan-1) S at levels comparable to human ACE2. Most single S substitutions (e.g., 452R, 478K, 501Y) did not significantly change virus entry, although 614G and 484K resulted in a decreased efficiency in viral entry.  Conversely, combinatorial VOC substitutions in the S protein were associated with significantly increased entry capacity of pseudotyped viruses compared to that of the parental Wuhan-1 pseudotyped virus. Similarly, infection studies using live ancestral (USA-WA1/2020), Alpha, and Beta SARS-CoV-2 viruses in hamsters revealed a higher replication potential for the Beta variant compared to the ancestral prototype virus. Moreover, neutralizing titers in sera from various animal species, including humans, were significantly reduced by single substitutions of 484K or 452R, double substitutions of 501Y-484K, 452R-484K and 452R-478K and the triple substitution of 501Y-484K-417N, suggesting that 484K and 452R are particularly important for evading neutralizing antibodies in human, cat, and rabbit sera. Cumulatively, this study reveals important insights into the host range of SARS-CoV-2 and the effect of recently emergent S protein substitutions on viral entry, virus replication and antibody-mediated viral neutralization.

scholarly journals Mucosal Immunization with Surface-Displayed Severe Acute Respiratory Syndrome Coronavirus Spike Protein on Lactobacillus casei Induces Neutralizing Antibodies in Mice

2006 ◽  
Vol 80 (8) ◽  
pp. 4079-4087 ◽  
Author(s):  
Jong-Soo Lee ◽  
Haryoung Poo ◽  
Dong P. Han ◽  
Seung-Pyo Hong ◽  
Kwang Kim ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Neutralizing Antibodies ◽  
Lactobacillus Casei ◽  
Effective Means ◽  
Neutralizing Antibody ◽  
Mucosal Immunization ◽  
S Protein ◽  
Recombinant Fusion Proteins ◽  
Effective Delivery ◽  
Surface Localization

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-γ-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.

scholarly journals Immunogenicity of Low-Dose Prime-Boost Vaccination of mRNA Vaccine CV07050101 in Non-Human Primates

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1645
Author(s):  
Neeltje van Doremalen ◽  
Robert J. Fischer ◽  
Jonathan E. Schulz ◽  
Myndi G. Holbrook ◽  
Brian J. Smith ◽  
...  
Keyword(s):  
Immune Responses ◽  
Neutralizing Antibodies ◽  
Vaccine Candidate ◽  
Small Animal ◽  
S Protein ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Boost Vaccination ◽  
Human Volunteers ◽  
Cellular Immune

Many different vaccine candidates against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of COVID-19, are currently approved and under development. Vaccine platforms vary from mRNA vaccines to viral-vectored vaccines, and several candidates have been shown to produce humoral and cellular responses in small animal models, non-human primates, and human volunteers. In this study, six non-human primates received a prime-boost intramuscular vaccination with 4 µg of mRNA vaccine candidate CV07050101, which encodes a pre-fusion stabilized spike (S) protein of SARS-CoV-2. Boost vaccination was performed 28 days post prime vaccination. As a control, six animals were similarly injected with PBS. Humoral and cellular immune responses were investigated at time of vaccination, and two weeks afterwards. No antibodies could be detected at two and four weeks after prime vaccination. Two weeks after boost vaccination, binding but no neutralizing antibodies were detected in four out of six non-human primates. SARS-CoV-2 S protein-specific T cell responses were detected in these four animals. In conclusion, prime-boost vaccination with 4 µg of vaccine candidate CV07050101 resulted in limited immune responses in four out of six non-human primates.

scholarly journals Antibodies and Vaccines Target RBD of SARS-CoV-2

2021 ◽  
Vol 8 ◽  
Author(s):  
Long Min ◽  
Qiu Sun
Keyword(s):  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Neutralizing Antibody ◽  
Protein S ◽  
The Novel ◽  
Global Public Health ◽  
Human Coronavirus ◽  
S Protein ◽  
Important Target ◽  
A Subunit

The novel human coronavirus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which gives rise to the coronavirus disease 2019 (COVID-19), has caused a serious threat to global public health. On March 11, 2020, the WHO had officially announced COVID-19 as a pandemic. Therefore, it is vital to find effective and safe neutralizing antibodies and vaccines for COVID-19. The critical neutralizing domain (CND) that is contained in the receptor-binding domain (RBD) of the spike protein (S protein) could lead to a highly potent neutralizing antibody response as well as the cross-protection of other strains of SARS. By using RBD as an antigen, many neutralizing antibodies are isolated that are essential to the therapeutics of COVID-19. Furthermore, a subunit vaccine, which is based on the RBD, is expected to be safer than others, thus the RBD in the S protein is a more important target for vaccine development. In this review, we focus on neutralizing antibodies that are targeting RBD as well as the vaccine based on RBD under current development.

scholarly journals DNA vaccine protection against SARS-CoV-2 in rhesus macaques

Science ◽  
2020 ◽  
Vol 369 (6505) ◽  
pp. 806-811 ◽  
Author(s):  
Jingyou Yu ◽  
Lisa H. Tostanoski ◽  
Lauren Peter ◽  
Noe B. Mercado ◽  
Katherine McMahan ◽  
...  
Keyword(s):  
Dna Vaccine ◽  
Protective Efficacy ◽  
Rhesus Macaques ◽  
Neutralizing Antibody ◽  
Vaccine Protection ◽  
S Protein ◽  
Viral Loads ◽  
Cellular Immune Responses ◽  
Antibody Titers ◽  
Cellular Immune

The global coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has made the development of a vaccine a top biomedical priority. In this study, we developed a series of DNA vaccine candidates expressing different forms of the SARS-CoV-2 spike (S) protein and evaluated them in 35 rhesus macaques. Vaccinated animals developed humoral and cellular immune responses, including neutralizing antibody titers at levels comparable to those found in convalescent humans and macaques infected with SARS-CoV-2. After vaccination, all animals were challenged with SARS-CoV-2, and the vaccine encoding the full-length S protein resulted in >3.1 and >3.7 log10 reductions in median viral loads in bronchoalveolar lavage and nasal mucosa, respectively, as compared with viral loads in sham controls. Vaccine-elicited neutralizing antibody titers correlated with protective efficacy, suggesting an immune correlate of protection. These data demonstrate vaccine protection against SARS-CoV-2 in nonhuman primates.

scholarly journals Protective humoral responses to severe acute respiratory syndrome-associated coronavirus: implications for the design of an effective protein-based vaccine

2004 ◽  
Vol 85 (10) ◽  
pp. 3109-3113 ◽  
Author(s):  
Hai Pang ◽  
Yinggang Liu ◽  
Xueqing Han ◽  
Yanhui Xu ◽  
Fuguo Jiang ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Structural Proteins ◽  
Effective Vaccine ◽  
S Protein ◽  
M Proteins ◽  
Humoral Responses

Some of the structural proteins of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) carry major epitopes involved in virus neutralization and are essential for the induction of protective humoral responses and the development of an effective vaccine. Rabbit antisera were prepared using full-length N and M proteins and eight expressed fragments covering the S protein. Antisera to S and M proteins were found to have different neutralizing titres towards SARS-CoV infection in vivo, ranging from 1 : 35 to 1 : 128. Antiserum to the N protein did not contain neutralizing antibodies. Epitopes inducing protective humoral responses to virus infection were located mainly in the M protein and a region spanning residues 13–877 of the S protein. The neutralizing ability of antisera directed against the expressed structural proteins was greater than that of convalescent patient antisera, confirming that, as immunogens, the former induce strong, SARS-CoV-specific neutralizing antibody responses. The in vitro neutralization assay has important implications for the design of an effective, protein-based vaccine preventing SARS-CoV infection.

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