scholarly journals A 219-mer CHO-Expressing Receptor-Binding Domain of SARS-CoV S Protein Induces Potent Immune Responses and Protective Immunity

2010 ◽  
Vol 23 (2) ◽  
pp. 211-219 ◽  
Author(s):  
Lanying Du ◽  
Guangyu Zhao ◽  
Chris CS Chan ◽  
Lin Li ◽  
Yuxian He ◽  
...  
Keyword(s):  
Immune Responses ◽  
Receptor Binding ◽  
Protective Immunity ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
S Protein

scholarly journals 480 Preliminary evaluation of a novel coronavirus vaccine (CORVax) using electroporation of plasmid DNA encoding a stabilized prefusion SARS-CoV-2 spike protein alone or with transfection of plasmid IL-12

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A514-A514
Author(s):  
Shawn Jensen ◽  
Christopher Twitty ◽  
Christopher Paustian ◽  
Madelein Laws ◽  
Glenna McDonnell ◽  
...  
Keyword(s):  
Immune Responses ◽  
Receptor Binding ◽  
Binding Domain ◽  
Tumor Rejection ◽  
Spike Protein ◽  
Preliminary Evaluation ◽  
List Type ◽  
Receptor Binding Domain ◽  
Igg Antibodies ◽  
Viral Neutralization

BackgroundSARS-CoV-2 (CoV2) has precipitated a global pandemic and the effectiveness of standard vaccine strategies to induce potent and persistent immunity to CoV2 is in question, particularly for the elderly. This problem is not dissimilar to what we have struggled with in our quest to induce immunity to cancer antigens, where vaccine-induced anti-cancer immune responses can be weak. Here, we describe a novel vaccine approach which leverages electroporation (EP) of a plasmid encoding a prefusion stabilized CoV2 spike protein (CORVax). As IL-12 has been shown to augment the efficacy of immunotherapy in aged mice,1 we have initiated studies to evaluate if plasmid IL-12 (TAVO™) can similarly augment anti-CoV2 immune responses in young mice and have planned studies in aged animals.MethodsA prefusion stabilized CoV2 spike plasmid expression vector was constructed, a master cell bank generated and clinical-grade plasmid manufactured. C57BL/6 and BALB/c were vaccinated via intramuscular (IM) and/or intradermal (ID) injection followed immediately by EP of plasmids encoding the CoV2 spike protein with or without plasmid-encoded murine IL-12 on days 1 and 14 or 21. Mice were followed for >120 days to assess safety. Splenocytes and serum were harvested at different time points to interrogate virus-specific cellular responses as well anti-spike IgG1/IgG2 antibody titers. A surrogate viral neutralization test (sVNT) assessed serum blockade of soluble hACE2R binding to immobilized CoV2 spike.ResultsPreliminary data shows that EP of CORVax alone or combined with IL-12 was safe. EP of CORVax was able to elicit anti-Spike IgG antibodies (IC50 = 1/2112), as well as IgG antibodies targeting the receptor binding domain of the Spike protein (IC50 = 1/965) approximately 40 days after the booster vaccination. In 2 of 2 experiments, CORVax combined with IL-12 significantly (P<0.0001) increased the sVNT titers at 2 months, but this benefit was lost by 3 months.ConclusionsEarly preclinical data shows that EP of CORVax can induce IgG responses to CoV2 Spike and the receptor binding domain (RBD) as well as apparent viral neutralizing activity. The addition of IL-12, at least transiently, increased sVNT titer. We plan to investigate alternate vaccine boosting strategies while extending these studies into aged animals and initiate a clinical trial in the near future.ReferencesRuby CE, Weinberg AD. OX40-Enhanced tumor rejection and effector T cell differentiation decreases with age. J Immunol2009;182:1481–9. https://doi.org/10.4049/jimmunol.182.3.1481.

scholarly journals Cross-reactive neutralization of SARS-CoV-2 by serum antibodies from recovered SARS patients and immunized animals

2020 ◽  
Vol 6 (45) ◽  
pp. eabc9999 ◽  
Author(s):  
Yuanmei Zhu ◽  
Danwei Yu ◽  
Yang Han ◽  
Hongxia Yan ◽  
Huihui Chong ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Receptor Binding ◽  
Binding Domain ◽  
Full Length ◽  
Receptor Binding Domain ◽  
Serum Antibodies ◽  
Serum Samples ◽  
S Protein ◽  
Novel Coronavirus

The current coronavirus disease 2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus genetically close to SARS-CoV. To investigate the effects of previous SARS-CoV infection on the ability to recognize and neutralize SARS-CoV-2, we analyzed 20 convalescent serum samples collected from individuals infected with SARS-CoV during the 2003 SARS outbreak. All patient sera reacted strongly with the S1 subunit and receptor binding domain (RBD) of SARS-CoV; cross-reacted with the S ectodomain, S1, RBD, and S2 proteins of SARS-CoV-2; and neutralized both SARS-CoV and SARS-CoV-2 S protein–driven infections. Analysis of antisera from mice and rabbits immunized with a full-length S and RBD immunogens of SARS-CoV verified cross-reactive neutralization against SARS-CoV-2. A SARS-CoV–derived RBD from palm civets elicited more potent cross-neutralizing responses in immunized animals than the RBD from a human SARS-CoV strain, informing strategies for development of universal vaccines against emerging coronaviruses.

scholarly journals Conjugation of Human β-Defensin 2 to Spike Protein Receptor-Binding Domain Induces Antigen-Specific Protective Immunity against Middle East Respiratory Syndrome Coronavirus Infection in Human Dipeptidyl Peptidase 4 Transgenic Mice

Vaccines ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 635
Author(s):  
Ju Kim ◽  
Ye Lin Yang ◽  
Yongsu Jeong ◽  
Yong-Suk Jang
Keyword(s):  
Middle East ◽  
Immune Responses ◽  
Receptor Binding ◽  
Dipeptidyl Peptidase ◽  
Binding Domain ◽  
Middle East Respiratory Syndrome ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Dipeptidyl Peptidase 4 ◽  
Protein Receptor

Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe acute respiratory symptoms. Due to the lack of medical countermeasures, effective and safe vaccines against MERS-CoV infection are urgently required. Although different types of candidate vaccines have been developed, their immunogenicity is limited, and the dose and administration route need optimization to achieve optimal protection. We here investigated the potential use of human β-defensin 2 (HBD 2) as an adjuvant to enhance the protection provided by MERS-CoV vaccination. We found that immunization of human dipeptidyl peptidase 4 (hDPP4)-transgenic (hDPP4-Tg) mice with spike protein receptor-binding domain (S RBD) conjugated with HBD 2 (S RBD-HBD 2) induced potent antigen (Ag)-specific adaptive immune responses and protected against MERS-CoV infection. In addition, immunization with S RBD-HBD 2 alleviated progressive pulmonary fibrosis in the lungs of MERS-CoV-infected hDPP4-Tg mice and suppressed endoplasmic reticulum stress signaling activation upon viral infection. Compared to intramuscular administration, intranasal administration of S RBD-HBD 2 induced more potent mucosal IgA responses and was more effective for protecting against intranasal MERS-CoV infection. In conclusion, our findings suggest that HBD 2 potentiates Ag-specific immune responses against viral Ag and can be used as an adjuvant enhancing the immunogenicity of subunit vaccine candidates against MERS-CoV.

scholarly journals Receptor-binding domain of SARS-CoV spike protein induces long-term protective immunity in an animal model

Vaccine ◽  
2007 ◽  
Vol 25 (15) ◽  
pp. 2832-2838 ◽  
Author(s):  
Lanying Du ◽  
Guangyu Zhao ◽  
Yuxian He ◽  
Yan Guo ◽  
Bo-Jian Zheng ◽  
...  
Keyword(s):  
Animal Model ◽  
Receptor Binding ◽  
Protective Immunity ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain

scholarly journals Recombinant Mycobacterium paragordonae Expressing SARS-CoV-2 Receptor-Binding Domain as a Vaccine Candidate Against SARS-CoV-2 Infections

2021 ◽  
Vol 12 ◽  
Author(s):  
Byoung-Jun Kim ◽  
Hyein Jeong ◽  
Hyejun Seo ◽  
Mi-Hyun Lee ◽  
Hyun Mu Shin ◽  
...  
Keyword(s):  
Immune Response ◽  
Single Dose ◽  
Immune Responses ◽  
Receptor Binding ◽  
Humoral Immune Response ◽  
Vaccine Candidate ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Live Virus ◽  
Humoral Immune

At present, concerns that the recent global emergence of SARS-CoV-2 variants could compromise the current vaccines have been raised, highlighting the urgent demand for new vaccines capable of eliciting T cell-mediated immune responses, as well as B cell-mediated neutralizing antibody production. In this study, we developed a novel recombinant Mycobacterium paragordonae expressing the SARS-CoV-2 receptor-binding domain (RBD) (rMpg-RBD-7) that is capable of eliciting RBD-specific immune responses in vaccinated mice. The potential use of rMpg-RBD-7 as a vaccine for SARS-CoV-2 infections was evaluated in in vivo using mouse models of two different modules, one for single-dose vaccination and the other for two-dose vaccination. In a single-dose vaccination model, we found that rMpg-RBD-7 versus a heat-killed strain could exert an enhanced cell-mediated immune (CMI) response, as well as a humoral immune response capable of neutralizing the RBD and ACE2 interaction. In a two-dose vaccination model, rMpg-RBD-7 in a two-dose vaccination could also exert a stronger CMI and humoral immune response to neutralize SARS-CoV-2 infections in pseudoviral or live virus infection systems, compared to single dose vaccinations of rMpg-RBD or two-dose RBD protein immunization. In conclusion, our data showed that rMpg-RBD-7 can lead to an enhanced CMI response and humoral immune responses in mice vaccinated with both single- or two-dose vaccination, highlighting its feasibility as a novel vaccine candidate for SARS-CoV-2. To the best of our knowledge, this study is the first in which mycobacteria is used as a delivery system for a SARS-CoV-2 vaccine.

scholarly journals Xeno-Nucleic Acid (XNA) 2’-Fluoro-Arabino Nucleic Acid (FANA) Aptamers to the Receptor-Binding Domain of SARS-CoV-2 S Protein Block ACE2 Binding

Viruses ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1983
Author(s):  
Irani Alves Ferreira-Bravo ◽  
Jeffrey J. DeStefano
Keyword(s):  
Nucleic Acid ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Dissociation Constants ◽  
High Specificity ◽  
Binding Domain ◽  
Host Cells ◽  
Receptor Binding Domain ◽  
S Protein ◽  
Equilibrium Dissociation Constants

The causative agent of COVID-19, SARS-CoV-2, gains access to cells through interactions of the receptor-binding domain (RBD) on the viral S protein with angiotensin-converting enzyme 2 (ACE2) on the surface of human host cells. Systematic evolution of ligands by exponential enrichment (SELEX) was used to generate aptamers (nucleic acids selected for high binding affinity to a target) to the RBD made from 2ʹ-fluoro-arabinonucleic acid (FANA). The best selected ~79 nucleotide aptamers bound the RBD (Arg319-Phe541) and the larger S1 domain (Val16-Arg685) of the 1272 amino acid S protein with equilibrium dissociation constants (KD,app) of ~10–20 nM, and binding half-life for the RBD, S1 domain, and full trimeric S protein of 53 ± 18, 76 ± 5, and 127 ± 7 min, respectively. Aptamers inhibited the binding of the RBD to ACE2 in an ELISA assay. Inhibition, on a per weight basis, was similar to neutralizing antibodies that were specific for RBD. Aptamers demonstrated high specificity, binding with about 10-fold lower affinity to the related S1 domain from the original SARS virus, which also binds to ACE2. Overall, FANA aptamers show affinities comparable to previous DNA aptamers to RBD and S1 protein and directly block receptor interactions while using an alternative Xeno-nucleic acid (XNA) platform.

scholarly journals Structural classification of neutralizing antibodies against the SARS-CoV-2 spike receptor-binding domain suggests vaccine and therapeutic strategies

2020 ◽  
Author(s):  
Christopher O. Barnes ◽  
Claudia A. Jette ◽  
Morgan E. Abernathy ◽  
Kim-Marie A. Dam ◽  
Shannon R. Esswein ◽  
...  
Keyword(s):  
Immune Responses ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Health Crisis ◽  
Naturally Occurring ◽  
Insight Into

AbstractThe COVID-19 pandemic presents an urgent health crisis. Human neutralizing antibodies (hNAbs) that target the host ACE2 receptor-binding domain (RBD) of the SARS-CoV-2 spike1–5 show therapeutic promise and are being evaluated clincally6–8. To determine structural correlates of SARS-CoV-2 neutralization, we solved 8 new structures of distinct COVID-19 hNAbs5 in complex with SARS-CoV-2 spike trimer or RBD. Structural comparisons allowed classification into categories: (1) VH3-53 hNAbs with short CDRH3s that block ACE2 and bind only to “up” RBDs, (2) ACE2-blocking hNAbs that bind both “up” and “down” RBDs and can contact adjacent RBDs, (3) hNAbs that bind outside the ACE2 site and recognize “up” and “down” RBDs, and (4) Previously-described antibodies that do not block ACE2 and bind only “up” RBDs9. Class 2 comprised four hNAbs whose epitopes bridged RBDs, including a VH3-53 hNAb that used a long CDRH3 with a hydrophobic tip to bridge between adjacent “down” RBDs, thereby locking spike into a closed conformation. Epitope/paratope mapping revealed few interactions with host-derived N-glycans and minor contributions of antibody somatic hypermutations to epitope contacts. Affinity measurements and mapping of naturally-occurring and in vitro-selected spike mutants in 3D provided insight into the potential for SARS-CoV-2 escape from antibodies elicited during infection or delivered therapeutically. These classifications and structural analyses provide rules for assigning current and future human RBD-targeting antibodies into classes, evaluating avidity effects, suggesting combinations for clinical use, and providing insight into immune responses against SARS-CoV-2.

Sign in / Sign up

Export Citation Format

Share Document