scholarly journals Immunogenicity of SARS-CoV: the Receptor-Binding Domain of S Protein is a Major Target of Neutralizing Antibodies

2006 ◽  
pp. 539-542 ◽  
Author(s):  
Yuxian He
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
S Protein ◽  
Major Target

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 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

2021 ◽  
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 2′-fluoroarabinonucleic 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 a binding half-life for the RBD of 53 ± 18 minutes. 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 S protein and directly block receptor interactions while using an alternative Xeno-nucleic acid (XNA) platform.

scholarly journals Yeast-Expressed SARS-CoV Recombinant Receptor-Binding Domain (RBD219-N1) Formulated with Aluminum Hydroxide Induces Protective Immunity and Reduces Immune Enhancement

2020 ◽  
Author(s):  
Wen-Hsiang Chen ◽  
Xinrong Tao ◽  
Anurodh Agrawal ◽  
Abdullah Algaissi ◽  
Bi-Hung Peng ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Pseudotyped Virus ◽  
Receptor Binding Domain ◽  
Protein Vaccine ◽  
S Protein ◽  
Recombinant Receptor ◽  
High Level

AbstractWe developed a severe acute respiratory syndrome (SARS) subunit recombinant protein vaccine candidate based on a high-yielding, yeast-engineered, receptor-binding domain (RBD219-N1) of the SARS beta-coronavirus (SARS-CoV) spike (S) protein. When formulated with Alhydrogel®, RBD219-N1 induced high-level neutralizing antibodies against both pseudotyped virus and a clinical (mouse-adapted) isolate of SARS-CoV. Here, we report that mice immunized with RBD219-N1/Alhydrogel® were fully protected from lethal SARS-CoV challenge (0% mortality), compared to ∼ 30% mortality in mice when immunized with the SARS S protein formulated with Alhydrogel®, and 100% mortality in negative controls. An RBD219-N1 formulation Alhydrogel® was also superior to the S protein, unadjuvanted RBD, and AddaVax (MF59-like adjuvant)-formulated RBD in inducing specific antibodies and preventing cellular infiltrates in the lungs upon SARS-CoV challenge. Specifically, a formulation with a 1:25 ratio of RBD219-N1 to Alhydrogel® provided high neutralizing antibody titers, 100% protection with non-detectable viral loads with minimal or no eosinophilic pulmonary infiltrates. As a result, this vaccine formulation is under consideration for further development against SARS-CoV and potentially other emerging and re-emerging beta-CoVs such as SARS-CoV-2.

scholarly journals Effects of Mutations in the Receptor-Binding Domain of SARS-CoV-2 Spike on its Binding Affinity to ACE2 and Neutralizing Antibodies Revealed by Computational Analysis

2021 ◽  
Author(s):  
Marine E Bozdaganyan ◽  
Olga S Sokolova ◽  
Konstantin V Shaitan ◽  
Mikhail P Kirpichnikov ◽  
Philipp S Orekhov
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Computational Analysis ◽  
Protein A ◽  
Experimental Studies ◽  
Point Mutations ◽  
Binding Domain ◽  
Single Amino Acid ◽  
Receptor Binding Domain ◽  
S Protein

SARS-CoV-2 causing coronavirus disease 2019 (COVID-19) is responsible for one of the most deleterious pandemics of our time. The interaction between the ACE2 receptors at the surface of human cells and the viral Spike (S) protein triggers the infection making the receptor-binding domain (RBD) of the SARS-CoV-2 S-protein a focal target for the neutralizing antibodies (Abs). Despite the recent progress in the development and deployment of vaccines, the emergence of novel variants of SARS-CoV-2 insensitive to Abs produced in response to the vaccine administration and/or monoclonal ones represents upcoming jeopardy. Here, we assessed the possible effects of single and multiple mutations in the RBD of SARS-CoV-2 S-protein on its binding energy to various antibodies and the human ACE2 receptor. The performed computational analysis indicates that while single amino acid replacements in RBD may only cause partial impairment of the Abs binding, moreover, limited to specific epitopes, some variants of SARS-CoV-2 (with as few as 8 mutations), which are already present in the population, may potentially result in a much broader antigenic escape. We also identified a number of point mutations, which, in contrast to the majority of replacements, reduce RBD affinity to various antibodies without affecting its binding to ACE2. Overall, the results provide guidelines for further experimental studies aiming at the identification of the high-risk RBD mutations allowing for an antigenic escape.

scholarly journals Stereotypic neutralizing VH antibodies against SARS-CoV-2 spike protein receptor binding domain in COVID-19 patients and healthy individuals

2021 ◽  
pp. eabd6990
Author(s):  
Sang Il Kim ◽  
Jinsung Noh ◽  
Sujeong Kim ◽  
Younggeun Choi ◽  
Duck Kyun Yoo ◽  
...  
Keyword(s):  
B Cells ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
De Novo ◽  
Binding Domain ◽  
Host Cells ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Healthy Individuals

Stereotypic antibody clonotypes exist in healthy individuals and may provide protective immunity against viral infections by neutralization. We observed that 13 out of 17 patients with COVID-19 had stereotypic variable heavy chain (VH) antibody clonotypes directed against the receptor-binding domain (RBD) of SARS-CoV-2 spike protein. These antibody clonotypes were comprised of immunoglobulin heavy variable (IGHV)3-53 or IGHV3-66 and immunoglobulin heavy joining (IGHJ)6 genes. These clonotypes included IgM, IgG3, IgG1, IgA1, IgG2, and IgA2 subtypes and had minimal somatic mutations, which suggested swift class switching after SARS-CoV-2 infection. The different immunoglobulin heavy variable chains were paired with diverse light chains resulting in binding to the RBD of SARS-CoV-2 spike protein. Human antibodies specific for the RBD can neutralize SARS-CoV-2 by inhibiting entry into host cells. We observed that one of these stereotypic neutralizing antibodies could inhibit viral replication in vitro using a clinical isolate of SARS-CoV-2. We also found that these VH clonotypes existed in six out of 10 healthy individuals, with IgM isotypes predominating. These findings suggest that stereotypic clonotypes can develop de novo from naïve B cells and not from memory B cells established from prior exposure to similar viruses. The expeditious and stereotypic expansion of these clonotypes may have occurred in patients infected with SARS-CoV-2 because they were already present.

scholarly journals mRNA vaccination boosts cross-variant neutralizing antibodies elicited by SARS-CoV-2 infection

Science ◽  
2021 ◽  
pp. eabg9175 ◽  
Author(s):  
Leonidas Stamatatos ◽  
Julie Czartoski ◽  
Yu-Hsin Wan ◽  
Leah J. Homad ◽  
Vanessa Rubin ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Previous Infection

Emerging SARS-CoV-2 variants have raised concerns about resistance to neutralizing antibodies elicited by previous infection or vaccination. We examined whether sera from recovered and naïve donors collected prior to, and following immunizations with existing mRNA vaccines, could neutralize the Wuhan-Hu-1 and B.1.351 variants. Pre-vaccination sera from recovered donors neutralized Wuhan-Hu-1 and sporadically neutralized B.1.351, but a single immunization boosted neutralizing titers against all variants and SARS-CoV-1 by up to 1000-fold. Neutralization was due to antibodies targeting the receptor binding domain and was not boosted by a second immunization. Immunization of naïve donors also elicited cross-neutralizing responses, but at lower titers. Our study highlights the importance of vaccinating both uninfected and previously infected persons to elicit cross-variant neutralizing antibodies.

scholarly journals Comprehensive Deep Mutational Scanning Reveals the Immune-Escaping Hotspots of SARS-CoV-2 Receptor-Binding Domain Targeting Neutralizing Antibodies

2021 ◽  
Vol 12 ◽  
Author(s):  
Keng-Chang Tsai ◽  
Yu-Ching Lee ◽  
Tien-Sheng Tseng
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Human Immune System ◽  
Angiotensin Converting Enzyme 2 ◽  
Study Results ◽  
Rapid Spread ◽  
Care Systems ◽  
Computational Analyses

The rapid spread of SARS-CoV-2 has caused the COVID-19 pandemic, resulting in the collapse of medical care systems and economic depression worldwide. To combat COVID-19, neutralizing antibodies have been investigated and developed. However, the evolutions (mutations) of the receptor-binding domain (RBD) of SARS-CoV-2 enable escape from neutralization by these antibodies, further impairing recognition by the human immune system. Thus, it is critical to investigate and predict the putative mutations of RBD that escape neutralizing immune responses. Here, we employed computational analyses to comprehensively investigate the mutational effects of RBD on binding to neutralizing antibodies and angiotensin-converting enzyme 2 (ACE2) and demonstrated that the RBD residues K417, L452, L455, F456, E484, G485, F486, F490, Q493, and S494 were consistent with clinically emerging variants or experimental observations of attenuated neutralizations. We also revealed common hotspots, Y449, L455, and Y489, that exerted comparable destabilizing effects on binding to both ACE2 and neutralizing antibodies. Our results provide valuable information on the putative effects of RBD variants on interactions with neutralizing antibodies. These findings provide insights into possible evolutionary hotspots that can escape recognition by these antibodies. In addition, our study results will benefit the development and design of vaccines and antibodies to combat the newly emerging variants of SARS-CoV-2.

scholarly journals Persistence and decay of human antibody responses to the receptor binding domain of SARS-CoV-2 spike protein in COVID-19 patients

2020 ◽  
Vol 5 (52) ◽  
pp. eabe0367 ◽  
Author(s):  
Anita S. Iyer ◽  
Forrest K. Jones ◽  
Ariana Nodoushani ◽  
Meagan Kelly ◽  
Margaret Becker ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Symptom Onset ◽  
Neutralizing Antibodies ◽  
Serum Antibody ◽  
Cross Reactivity ◽  
Binding Domain ◽  
Antibody Responses ◽  
Human Antibody ◽  
Receptor Binding Domain ◽  
Recent Infection

We measured plasma and/or serum antibody responses to the receptor-binding domain (RBD) of the spike (S) protein of SARS-CoV-2 in 343 North American patients infected with SARS-CoV-2 (of which 93% required hospitalization) up to 122 days after symptom onset and compared them to responses in 1548 individuals whose blood samples were obtained prior to the pandemic. After setting seropositivity thresholds for perfect specificity (100%), we estimated sensitivities of 95% for IgG, 90% for IgA, and 81% for IgM for detecting infected individuals between 15 and 28 days after symptom onset. While the median time to seroconversion was nearly 12 days across all three isotypes tested, IgA and IgM antibodies against RBD were short-lived with median times to seroreversion of 71 and 49 days after symptom onset. In contrast, anti-RBD IgG responses decayed slowly through 90 days with only 3 seropositive individuals seroreverting within this time period. IgG antibodies to SARS-CoV-2 RBD were strongly correlated with anti-S neutralizing antibody titers, which demonstrated little to no decrease over 75 days since symptom onset. We observed no cross-reactivity of the SARS-CoV-2 RBD-targeted antibodies with other widely circulating coronaviruses (HKU1, 229 E, OC43, NL63). These data suggest that RBD-targeted antibodies are excellent markers of previous and recent infection, that differential isotype measurements can help distinguish between recent and older infections, and that IgG responses persist over the first few months after infection and are highly correlated with neutralizing antibodies.

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