scholarly journals Neutralizing antibodies targeting the SARS‐CoV ‐2 receptor binding domain isolated from a naïve human antibody library

2021 ◽  
Author(s):  
Benjamin N. Bell ◽  
Abigail E. Powell ◽  
Carlos Rodriguez ◽  
Jennifer R. Cochran ◽  
Peter S. Kim
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Binding Domain ◽  
Human Antibody ◽  
Receptor Binding Domain ◽  
Antibody Library

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.

scholarly journals Isolation of a human monoclonal antibody specific for the receptor binding domain of SARS-CoV-2 using a competitive phage biopanning strategy

2020 ◽  
Vol 3 (2) ◽  
pp. 95-100 ◽  
Author(s):  
Xin Zeng ◽  
Lingfang Li ◽  
Jing Lin ◽  
Xinlei Li ◽  
Bin Liu ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Magnetic Beads ◽  
Human Monoclonal Antibody ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Antibody Library ◽  
Synthetic Antibody ◽  
Blocking Antibodies

Abstract The infection of the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused more than 200 000 deaths, but no vaccine or therapeutic monoclonal antibody is currently available. SARS-CoV-2 relies on its spike protein, in particular the receptor-binding domain (RBD), to bind human cell receptor angiotensin-converting enzyme 2 (ACE2) for viral entry, and thus targeting RBD holds the promise for preventing SARS-CoV-2 infection. In this work, a competitive biopanning strategy of a phage display antibody library was applied to screen blocking antibodies against RBD. High-affinity antibodies were enriched after the first round using a standard panning process in which RBD-His was immobilized as a bait. At the next two rounds, immobilized ACE2-Fc and free RBD-His were mixed with the enriched phage antibodies. Antibodies binding to RBD at epitopes different from ACE2-binding site were captured by the immobilized ACE2-Fc, forming a “sandwich” complex. Only antibodies competed with ACE2 can bind to the free RBD-His in the supernatant and be subsequently separated by the nickel-nitrilotriacetic acid magnetic beads. rRBD-15 from the competitive biopanning of our synthetic antibody library, Lib AB1, was produced as the full-length IgG1 format. It was proved to competitively block the binding of RBD to ACE2 and potently inhibit SARS-CoV-2 pseudovirus infection with IC50 values of 12 nM. Nevertheless, rRBD-16 from the standard biopanning can only bind to RBD in vitro, but not have the blocking or neutralization activity. Our strategy can efficiently isolate the blocking antibodies of RBD, and it would speed up the discovery of neutralizing antibodies against SARS-CoV-2.

scholarly journals Enhancement of SARS-CoV-2 Receptor Binding Domain -CR3022 Human Antibody Binding Affinity via in Silico Engineering Approach

2020 ◽  
Author(s):  
Fateme Sefid ◽  
Zahra Payandeh ◽  
Ghasem Azamirad ◽  
Behzad Mansoori ◽  
Behzad Baradaran ◽  
...  
Keyword(s):  
Amino Acids ◽  
Binding Affinity ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Affinity Maturation ◽  
Binding Domain ◽  
Human Antibody ◽  
Receptor Binding Domain ◽  
Receptor Binding Site ◽  
Specificity And Sensitivity

Abstract Background: The nCoV-2019 is a cause of COVID-19 disease. The surface spike glycoprotein (S), which is necessary for virus entry through the intervention of the host receptor and it mediates virus-host membrane fusion, is the primary coronavirus antigen (Ag). The angiotensin-converting enzyme 2 (ACE2) is reported to be the effective human receptor for SARS-CoVs 2. ACE2 receptor can be prevented by neutralizing antibodies (nAbs) such as CR3022 targeting the virus receptor-binding site. Considering the importance of computational docking, and affinity maturation we aimed to find the important amino acids of the CR3022 antibody (Ab). These amino acids were then replaced by other amino acids to improve Ab-binding affinity to a receptor-binding domain (RBD) of the 2019-nCoV spike protein. Finally, we measured the binding affinity of Ab variants to the Ag. Result: Our findings disclosed that several variant mutations could successfully improve the characteristics of the Ab binding compared to the normal antibodies. Conclusion: The modified antibodies may be possible candidates for stronger affinity binding to Ags which in turn can affect the specificity and sensitivity of antibodies.

scholarly journals Neutralizing antibodies targeting the SARS-CoV-2 receptor binding domain isolated from a naïve human antibody library

2021 ◽  
Author(s):  
Benjamin Nikola Bell ◽  
Abigail E. Powell ◽  
Carlos Rodriguez ◽  
Jennifer R Cochran ◽  
Peter S. Kim
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
In Vitro Selection ◽  
Surface Display ◽  
Binding Domain ◽  
Yeast Surface Display ◽  
Surface Glycoprotein ◽  
Human Antibody ◽  
Receptor Binding Domain

Infection with SARS-CoV-2 elicits robust antibody responses in some patients, with a majority of the response directed at the receptor binding domain (RBD) of the spike surface glycoprotein. Remarkably, many patient-derived antibodies that potently inhibit viral infection harbor few to no mutations from the germline, suggesting that naive antibody libraries are a viable means for discovery of novel SARS-CoV-2 neutralizing antibodies. Here, we used a yeast surface-display library of human naive antibodies to isolate and characterize three novel neutralizing antibodies that target the RBD: one that blocks interaction with angiotensin-converting enzyme 2 (ACE2), the human receptor for SARS-CoV-2, and two that target other epitopes on the RBD. These three antibodies neutralized SARS-CoV-2 spike-pseudotyped lentivirus with IC50 values as low as 60 ng/mL in vitro. Using a biolayer interferometry-based binding competition assay, we determined that these antibodies have distinct but overlapping epitopes with antibodies elicited during natural COVID-19 infection. Taken together, these analyses highlight how in vitro selection of naive antibodies can mimic the humoral response in vivo, yielding neutralizing antibodies and various epitopes that can be effectively targeted on the SARS-CoV-2 RBD.

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.

Construction and immunogenic studies of a mFc fusion receptor binding domain (RBD) of spike protein as a subunit vaccine against SARS-CoV-2 infection

2020 ◽  
Vol 56 (61) ◽  
pp. 8683-8686 ◽  
Author(s):  
Xiaoxiao Qi ◽  
Bixia Ke ◽  
Qian Feng ◽  
Deying Yang ◽  
Qinghai Lian ◽  
...  
Keyword(s):  
Amino Acid ◽  
Fusion Protein ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Subunit Vaccine ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Humoral And Cellular Immunity ◽  
A Subunit

Herein, we report that a recombinant fusion protein, containing a 457 amino acid SARS-CoV-2 receptor binding domain and a mouse IgG1 Fc domain, could induce highly potent neutralizing antibodies and stimulate humoral and cellular immunity in mice.

scholarly journals Computational Prediction of the Epitopes of HA1 Protein of Influenza Viruses to its Neutralizing Antibodies

Antibodies ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 2
Author(s):  
Xiaoyan Zeng ◽  
Fiona Legge ◽  
Chao Huang ◽  
Xiao Zhang ◽  
Yongjun Jiao ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Crystal Structures ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Computational Prediction ◽  
Binding Domain ◽  
Influenza Viruses ◽  
New Method ◽  
Receptor Binding Domain ◽  
Antibody Recognition

In this work, we have used a new method to predict the epitopes of HA1 protein of influenza virus to several antibodies HC19, CR9114, BH151 and 4F5. While our results reproduced the binding epitopes of H3N2 or H5N1 for the neutralizing antibodies HC19, CR9114, and BH151 as revealed from the available crystal structures, additional epitopes for these antibodies were also suggested. Moreover, the predicted epitopes of H5N1 HA1 for the newly developed antibody 4F5 are located at the receptor binding domain, while previous study identified a region 76-WLLGNP-81 as the epitope. The possibility of antibody recognition of influenza virus via different mechanism by binding to different epitopes of an antigen is also discussed.

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