scholarly journals Synthetic antibodies neutralize SARS-CoV-2 infection of mammalian cells

Author(s):  
Shane Miersch ◽  
Mart Ustav ◽  
Zhijie Li ◽  
James B. Case ◽  
Safder Ganaie ◽  
...  

ABSTRACTCoronaviruses (CoV) are a large family of enveloped, RNA viruses that circulate in mammals and birds. Three highly pathogenic strains have caused zoonotic infections in humans that result in severe respiratory syndromes including the Middle East Respiratory Syndrome CoV (MERS), Severe Acute Respiratory Syndrome CoV (SARS), and the ongoing Coronavirus Disease 2019 (COVID-19) pandemic. Here, we describe a panel of synthetic monoclonal antibodies, built on a human IgG framework, that bind to the spike protein of SARS-CoV-2 (the causative agent of COVID-19), compete for ACE2 binding, and potently inhibit SARS-CoV-2. All antibodies that exhibited neutralization potencies at sub-nanomolar concentrations against SARS-CoV-2/USA/WA1 in Vero E6 cells, also bound to the receptor binding domain (RBD), suggesting competition for the host receptor ACE2. These antibodies represent strong immunotherapeutic candidates for treatment of COVID-19.

mBio ◽  
2021 ◽  
Author(s):  
Wen Su ◽  
Sin Fun Sia ◽  
Aaron J. Schmitz ◽  
Traci L. Bricker ◽  
Tyler N. Starr ◽  
...  

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein is the main target for neutralizing antibodies. These antibodies can be elicited through immunization or passively transferred as therapeutics in the form of convalescent-phase sera or monoclonal antibodies (MAbs).


2021 ◽  
Author(s):  
Laura VanBlargan ◽  
John Errico ◽  
Peter Halfmann ◽  
Seth Zost ◽  
James Crowe ◽  
...  

Abstract The emergence of the highly-transmissible B.1.1.529 Omicron variant of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is concerning for antibody countermeasure efficacy because of the number of mutations in the spike protein. Here, we tested a panel of anti-receptor binding domain monoclonal antibodies (mAbs) corresponding to those in clinical use by Vir Biotechnology (S309, the parent mAb of VIR-7831 [Sotrovimab]), AstraZeneca (COV2-2196 and COV2-2130, the parent mAbs of AZD8895 and AZD1061), Regeneron (REGN10933 and REGN10987), Lilly (LY-CoV555 and LY-CoV016), and Celltrion (CT-P59) for their ability to neutralize an infectious B.1.1.529 Omicron isolate. Several mAbs (LY-CoV555, LY-CoV016, REGN10933, REGN10987, and CT-P59) completely lost neutralizing activity against B.1.1.529 virus in both Vero-TMPRSS2 and Vero-hACE2-TMPRSS2 cells, whereas others were reduced (COV2-2196 and COV2-2130 combination, ~12-fold decrease) or minimally affected (S309). Our results suggest that several, but not all, of the antibodies in clinical use may lose efficacy against the B.1.1.529 Omicron variant.


Science ◽  
2020 ◽  
Vol 369 (6504) ◽  
pp. 650-655 ◽  
Author(s):  
Xiangyang Chi ◽  
Renhong Yan ◽  
Jun Zhang ◽  
Guanying Zhang ◽  
Yuanyuan Zhang ◽  
...  

Developing therapeutics against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could be guided by the distribution of epitopes, not only on the receptor binding domain (RBD) of the Spike (S) protein but also across the full Spike (S) protein. We isolated and characterized monoclonal antibodies (mAbs) from 10 convalescent COVID-19 patients. Three mAbs showed neutralizing activities against authentic SARS-CoV-2. One mAb, named 4A8, exhibits high neutralization potency against both authentic and pseudotyped SARS-CoV-2 but does not bind the RBD. We defined the epitope of 4A8 as the N-terminal domain (NTD) of the S protein by determining with cryo–eletron microscopy its structure in complex with the S protein to an overall resolution of 3.1 angstroms and local resolution of 3.3 angstroms for the 4A8-NTD interface. This points to the NTD as a promising target for therapeutic mAbs against COVID-19.


2021 ◽  
Author(s):  
Patrick Wilson ◽  
Siriruk Changrob ◽  
Yanbin Fu ◽  
Jenna Guthmiller ◽  
Peter Halfmann ◽  
...  

Abstract Several severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants have arisen that exhibit increased viral transmissibility and partial evasion of immunity induced by natural infection and vaccination. To address the specific antibody targets that were affected by recent viral variants, we generated 43 monoclonal antibodies (mAbs) from 10 convalescent donors that bound three distinct domains of the SARS-CoV-2 spike. Viral variants harboring mutations at K417, E484 and N501 could escape most of the highly potent antibodies against the receptor binding domain (RBD). Despite this, we identified 12 neutralizing mAbs against three distinct regions of the spike protein that neutralize SARS-CoV-2 and the variants of concern, including B.1.1.7 (alpha), P.1 (gamma) and B.1.617.2 (delta). Notably, antibodies targeting distinct epitopes could neutralize discrete variants, suggesting different variants may have evolved to disrupt the binding of particular neutralizing antibody classes. These results underscore that humans exposed to wildtype (WT) SARS-CoV-2 do possess neutralizing antibodies against current variants and that it is critical to induce antibodies targeting multiple distinct epitopes of the spike that can neutralize emerging variants of concern.


2020 ◽  
Vol 94 (17) ◽  
Author(s):  
Zhe Liu ◽  
Huanying Zheng ◽  
Huifang Lin ◽  
Mingyue Li ◽  
Runyu Yuan ◽  
...  

ABSTRACT Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus first identified in December 2019. Notable features that make SARS-CoV-2 distinct from most other previously identified betacoronaviruses include a receptor binding domain and a unique insertion of 12 nucleotides or 4 amino acids (PRRA) at the S1/S2 boundary. In this study, we identified two deletion variants of SARS-CoV-2 that either directly affect the polybasic cleavage site itself (NSPRRAR) or a flanking sequence (QTQTN). These deletions were verified by multiple sequencing methods. In vitro results showed that the deletion of NSPRRAR likely does not affect virus replication in Vero and Vero-E6 cells; however, the deletion of QTQTN may restrict late-phase viral replication. The deletion of QTQTN was detected in 3 of 68 clinical samples and 12 of 24 in vitro-isolated viruses, while the deletion of NSPRRAR was identified in 3 in vitro-isolated viruses. Our data indicate that (i) there may be distinct selection pressures on SARS-CoV-2 replication or infection in vitro and in vivo; (ii) an efficient mechanism for deleting this region from the viral genome may exist, given that the deletion variant is commonly detected after two rounds of cell passage; and (iii) the PRRA insertion, which is unique to SARS-CoV-2, is not fixed during virus replication in vitro. These findings provide information to aid further investigation of SARS-CoV-2 infection mechanisms and a better understanding of the NSPRRAR deletion variant observed here. IMPORTANCE The spike protein determines the infectivity and host range of coronaviruses. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has two unique features in its spike protein, the receptor binding domain and an insertion of 12 nucleotides at the S1/S2 boundary resulting in a furin-like cleavage site. Here, we identified two deletion variants of SARS-CoV-2 that either directly affect the furin-like cleavage site itself (NSPRRAR) or a flanking sequence (QTQTN), and we investigated these deletions in cell isolates and clinical samples. The absence of the polybasic cleavage site in SARS-CoV-2 did not affect virus replication in Vero or Vero-E6 cells. Our data indicate the PRRAR sequence and the flanking QTQTN sequence are not fixed in vitro; thus, there appears to be distinct selection pressures on SARS-CoV-2 sequences in vitro and in vivo. Further investigation of the mechanism of generating these deletion variants and their infectivity in different animal models would improve our understanding of the origin and evolution of this virus.


2021 ◽  
Author(s):  
Shuo Du ◽  
Pulan Liu ◽  
Zhiying Zhang ◽  
Tianhe Xiao ◽  
Ayijiang Yasimayi ◽  
...  

The spread of the SARS-CoV-2 variants could seriously dampen the global effort to tackle the COVID-19 pandemic. Recently, we investigated the humoral antibody responses of SARS-CoV-2 convalescent patients and vaccinees towards circulating variants, and identified a panel of monoclonal antibodies (mAbs) that could efficiently neutralize the B.1.351 (Beta) variant. Here we investigate how these mAbs target the B.1.351 spike protein using cryo-electron microscopy. In particular, we show that two superpotent mAbs, BD-812 and BD-836, have non-overlapping epitopes on the receptor-binding domain (RBD) of spike. Both block the interaction between RBD and the ACE2 receptor; and importantly, both remain fully efficacious towards the B.1.617.1 (Kappa) and B.1.617.2 (Delta) variants. The BD-812/BD-836 pair could thus serve as an ideal antibody cocktail against the SARS-CoV-2 VOCs.


2021 ◽  
Author(s):  
Takuya Tada ◽  
Belinda M. Dcosta ◽  
Hao Zhou ◽  
Ada Vaill ◽  
Wes Kazmierski ◽  
...  

AbstractMonoclonal antibodies against the SARS-CoV-2 spike protein, notably, those developed by Regeneron Pharmaceuticals and Eli Lilly and Company have proven to provide protection against severe COVID-19. The emergence of SARS-CoV-2 variants with heavily mutated spike proteins raises the concern that the therapy could become less effective if any of the mutations disrupt epitopes engaged by the antibodies. In this study, we tested monoclonal antibodies REGN10933 and REGN10987 that are used in combination, for their ability to neutralize SARS-CoV-2 variants B.1.1.7, B.1.351, mink cluster 5 and COH.20G/677H. We report that REGN10987 maintains most of its neutralization activity against viruses with B.1.1.7, B.1.351 and mink cluster 5 spike proteins but that REGN10933 has lost activity against B.1.351 and mink cluster 5. The failure of REGN10933 to neutralize B.1.351 is caused by the K417N and E484K mutations in the receptor binding domain; the failure to neutralize the mink cluster 5 spike protein is caused by the Y453F mutation. The REGN10933 and REGN10987 combination was 9.1-fold less potent on B.1.351 and 16.2-fold less potent on mink cluster 5, raising concerns of reduced efficacy in the treatment of patients infected with variant viruses. The results suggest that there is a need to develop additional monoclonal antibodies that are not affected by the current spike protein mutations.


2021 ◽  
Author(s):  
Sabrina Lusvarghi ◽  
Wei Wang ◽  
Rachel Herrup ◽  
Sabari Nath Neerukonda ◽  
Russell Vassell ◽  
...  

Mutations in the spike protein of SARS-CoV-2 variants can compromise the effectiveness of therapeutic antibodies. Most clinical-stage therapeutic antibodies target the spike receptor binding domain (RBD), but variants often have multiple mutations in several spike regions. To help predict antibody potency against emerging variants, we evaluated 25 clinical-stage therapeutic antibodies for neutralization activity against 60 pseudoviruses bearing spikes with single or multiple substitutions in several spike domains, including the full set of substitutions in B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), B.1.429 (Epsilon), B.1.526 (Iota), A.23.1 and R.1 variants. We found that 14 of 15 single antibodies were vulnerable to at least one RBD substitution, but most combination and polyclonal therapeutic antibodies remained potent. Key substitutions in variants with multiple spike substitutions predicted resistance, but the degree of resistance could be modified in unpredictable ways by other spike substitutions that may reside outside of the RBD. These findings highlight the importance of assessing antibody potency in the context of all substitutions in a variant and show that epistatic interactions in spike can modify virus susceptibility to therapeutic antibodies.


2021 ◽  
Vol 17 (8) ◽  
pp. e1009857
Author(s):  
Michelle N. Vu ◽  
Vineet D. Menachery

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) emerged as a virus with a pathogenicity closer to Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) and Middle East Respiratory Syndrome Coronavirus (MERS-CoV) and a transmissibility similar to common cold coronaviruses (CoVs). In this review, we briefly discuss the features of the receptor-binding domain (RBD) and protease cleavage of the SARS-CoV-2 spike protein that enable SARS-CoV-2 to be a pandemic virus.


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