scholarly journals Opsonization by non-neutralizing antibodies can confer protection to SARS-CoV-2 despite Spike-dependent modulation of phagocytosis

2021 ◽  
Author(s):  
Wael Bahnan ◽  
Sebastian Wrighton ◽  
Martin Sundwall ◽  
Anna Bläckberg ◽  
Olivia Larsson ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Neutralizing Antibodies ◽  
Antibody Binding ◽  
Spike Protein ◽  
Infection Model ◽  
Immune Functions ◽  
Immune Mechanism ◽  
Neutralization Potential ◽  
Specific Antibodies ◽  
Low Levels

Spike-specific antibodies are central to effective COVID19 immunity. Research efforts have focused on antibodies that neutralize the ACE2-Spike interaction but not on non-neutralizing antibodies. Antibody-dependent phagocytosis is an immune mechanism enhanced by opsonization, where typically, more bound antibodies trigger a stronger phagocyte response. Here, we show that Spike-specific antibodies, dependent on concentration, can either enhance or reduce Spike-bead phagocytosis by monocytes independently of the antibody neutralization potential. Surprisingly, we find that both convalescent patient plasma and patient-derived monoclonal antibodies lead to maximum opsonization already at low levels of bound antibodies and is reduced as antibody binding to Spike protein increases. Moreover, we show that this Spike-dependent modulation of opsonization seems to affect the outcome in an experimental SARS-CoV-2 infection model. These results suggest that the levels of anti-Spike antibodies could influence monocyte-mediated immune functions and propose that non-neutralizing antibodies could confer protection to SARS-CoV-2 infection by mediating phagocytosis.

scholarly journals Spike-Dependent Opsonization Indicates Both Dose-Dependent Inhibition of Phagocytosis and That Non-Neutralizing Antibodies Can Confer Protection to SARS-CoV-2

2022 ◽  
Vol 12 ◽  
Author(s):  
Wael Bahnan ◽  
Sebastian Wrighton ◽  
Martin Sundwall ◽  
Anna Bläckberg ◽  
Olivia Larsson ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Infection Model ◽  
Immune Functions ◽  
Immune Mechanism ◽  
Neutralization Potential ◽  
Specific Antibodies ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Low Levels ◽  
Dose Dependent

Spike-specific antibodies are central to effective COVID19 immunity. Research efforts have focused on antibodies that neutralize the ACE2-Spike interaction but not on non-neutralizing antibodies. Antibody-dependent phagocytosis is an immune mechanism enhanced by opsonization, where typically, more bound antibodies trigger a stronger phagocyte response. Here, we show that Spike-specific antibodies, dependent on concentration, can either enhance or reduce Spike-bead phagocytosis by monocytes independently of the antibody neutralization potential. Surprisingly, we find that both convalescent patient plasma and patient-derived monoclonal antibodies lead to maximum opsonization already at low levels of bound antibodies and is reduced as antibody binding to Spike protein increases. Moreover, we show that this Spike-dependent modulation of opsonization correlate with the outcome in an experimental SARS-CoV-2 infection model. These results suggest that the levels of anti-Spike antibodies could influence monocyte-mediated immune functions and propose that non-neutralizing antibodies could confer protection to SARS-CoV-2 infection by mediating phagocytosis.

scholarly journals A pair of non-competing neutralizing human monoclonal antibodies protecting from disease in a SARS-CoV-2 infection model

2021 ◽  
Author(s):  
Antonia Sophia Peter ◽  
Edith Roth ◽  
Sebastian R. Schulz ◽  
Kirsten Fraedrich ◽  
Tobit Steinmetz ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Neutralizing Antibodies ◽  
Human Immunoglobulin ◽  
Spike Protein ◽  
Infection Model ◽  
Immunoglobulin Gene ◽  
Binding Studies ◽  
Human Monoclonal Antibodies ◽  
Region Gene ◽  
Viral Spread

TRIANNI mice carry an entire set of human immunoglobulin V region gene segments and are a powerful tool to rapidly generate human monoclonal antibodies. After immunizing these mice against the spike protein of SARS-CoV-2, we identified 29 hybridoma antibodies that reacted with the SARS-CoV-2 spike protein. Nine antibodies neutralized SARS-CoV-2 infection at IC50 values in the subnanomolar range. ELISA-binding studies and DNA sequence analyses revealed one cluster of clonally related neutralizing antibodies that target the receptor-binding domain and compete with the cellular receptor hACE2. A second cluster of neutralizing antibodies binds to the N-terminal domain of the spike protein without competing with the binding of hACE2 or cluster 1 antibodies. SARS-CoV-2 mutants selected for resistance to an antibody from one cluster are still neutralized by an antibody from the other cluster. Antibodies from both clusters markedly reduced viral spread in mice transgenic for human ACE2 and protected the animals from SARS-CoV-2 induced weight loss. Thus, we report two clusters of potent non-competing SARS-CoV-2 neutralizing antibodies providing potential candidates for therapy and prophylaxis of COVID-19. The study further supports the use of transgenic animals with human immunoglobulin gene repertoires in pandemic preparedness initiatives.

scholarly journals Extremely potent monoclonal antibodies neutralize Omicron and other SARS-CoV-2 variants

2022 ◽  
Author(s):  
Zhaochun Chen ◽  
Peng Zhang ◽  
Yumiko Matsuoka ◽  
Yaroslav Tsybovsky ◽  
Kamille West ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Neutralizing Antibodies ◽  
Spike Protein ◽  
Structural Basis ◽  
Hamster Model ◽  
Golden Syrian Hamster ◽  
Phage Display Libraries ◽  
Antibody Phage ◽  
Antibody Phage Display ◽  
Early Isolate

The ongoing coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has triggered a devastating global health, social and economic crisis. The RNA nature and broad circulation of this virus facilitate the accumulation of mutations, leading to the continuous emergence of variants of concern with increased transmissibility or pathogenicity1. This poses a major challenge to the effectiveness of current vaccines and therapeutic antibodies1,2. Thus, there is an urgent need for effective therapeutic and preventive measures with a broad spectrum of action, especially against variants with an unparalleled number of mutations such as the recently emerged Omicron variant, which is rapidly spreading across the globe3. Here, we used combinatorial antibody phage-display libraries from convalescent COVID-19 patients to generate monoclonal antibodies against the receptor-binding domain of the SARS-CoV-2 spike protein with ultrapotent neutralizing activity. One such antibody, NE12, neutralizes an early isolate, the WA-1 strain, as well as the Alpha and Delta variants with half-maximal inhibitory concentrations at picomolar level. A second antibody, NA8, has an unusual breadth of neutralization, with picomolar activity against both the Beta and Omicron variants. The prophylactic and therapeutic efficacy of NE12 and NA8 was confirmed in preclinical studies in the golden Syrian hamster model. Analysis by cryo-EM illustrated the structural basis for the neutralization properties of NE12 and NA8. Potent and broadly neutralizing antibodies against conserved regions of the SARS-CoV-2 spike protein may play a key role against future variants of concern that evade immune control.

scholarly journals Neutralizing Monoclonal Antibodies That Target the Spike Receptor Binding Domain Confer Fc Receptor-Independent Protection against SARS-CoV-2 Infection in Syrian Hamsters

mBio ◽  
2021 ◽  
Author(s):  
Wen Su ◽  
Sin Fun Sia ◽  
Aaron J. Schmitz ◽  
Traci L. Bricker ◽  
Tyler N. Starr ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Severe Acute Respiratory Syndrome ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Fc Receptor ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Syrian Hamsters ◽  
Convalescent Phase ◽  
Main Target

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).

scholarly journals Structures of SARS-CoV-2 B.1.351 neutralizing antibodies provide insights into cocktail design against concerning variants

2021 ◽  
Author(s):  
Shuo Du ◽  
Pulan Liu ◽  
Zhiying Zhang ◽  
Tianhe Xiao ◽  
Ayijiang Yasimayi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Monoclonal Antibodies ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Antibody Responses ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Humoral Antibody ◽  
Cryo Electron Microscopy ◽  
Antibody Cocktail

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.

scholarly journals SARS-CoV-2 501Y.V2 escapes neutralization by South African COVID-19 donor plasma

2021 ◽  
Author(s):  
Constantinos Kurt Wibmer ◽  
Frances Ayres ◽  
Tandile Hermanus ◽  
Mashudu Madzivhandila ◽  
Prudence Kgagudi ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
South African ◽  
Neutralizing Antibodies ◽  
Spike Protein ◽  
Donor Plasma

AbstractSARS-CoV-2 501Y.V2, a novel lineage of the coronavirus causing COVID-19, contains multiple mutations within two immunodominant domains of the spike protein. Here we show that this lineage exhibits complete escape from three classes of therapeutically relevant monoclonal antibodies. Furthermore 501Y.V2 shows substantial or complete escape from neutralizing antibodies in COVID-19 convalescent plasma. These data highlight the prospect of reinfection with antigenically distinct variants and may foreshadow reduced efficacy of current spike-based vaccines.

scholarly journals High-Resolution Mapping of Human Norovirus Antigens via Genomic Phage Display Library Selections and Deep Sequencing

2020 ◽  
Vol 95 (1) ◽  
Author(s):  
Wanzhi Huang ◽  
Victoria Soeung ◽  
David M. Boragine ◽  
Liya Hu ◽  
B. V. Venkataram Prasad ◽  
...  
Keyword(s):  
Immune Response ◽  
Monoclonal Antibodies ◽  
Deep Sequencing ◽  
Binding Sites ◽  
Neutralizing Antibodies ◽  
Phage Display Library ◽  
Antibody Binding ◽  
Affinity Selection ◽  
Humoral Immune ◽  
Polyclonal Antisera

ABSTRACT Norovirus (NoV) infections are a leading cause of gastroenteritis. The humoral immune response plays an important role in the control of NoV, and recent studies have identified neutralizing antibodies that bind the capsid protein VP1 to block viral infection. Here, we utilize a NoV GI.1 Jun-Fos-assisted phage display library constructed from randomly fragmented genomic DNA coupled with affinity selection for antibody binding and subsequent deep sequencing to map epitopes. The epitopes were identified by quantitating the phage clones before and after affinity selection and aligning the sequences of the most enriched peptides. The HJT-R3-A9 single-chain variable fragment (scFv) antibody epitope was mapped to a 12-amino-acid region of VP1 that is also the binding site for several previously identified monoclonal antibodies. We synthesized the 12-mer peptide and found that it binds the scFv antibody with a KD (equilibrium dissociation constant) of 46 nM. Further, alignment of enriched peptides after affinity selection on rabbit anti-NoV polyclonal antisera revealed five families of overlapping sequences that define distinct epitopes in VP1. One of these is identical to the HJT-R3-A9 scFv epitope, further suggesting that it is immunodominant. Similarly, other epitopes identified using the polyclonal antisera overlap binding sites for previously reported monoclonal antibodies, suggesting that they are also dominant epitopes. The results demonstrate that affinity selection and deep sequencing of the phage library provide sufficient resolution to map multiple epitopes simultaneously from complex samples such as polyclonal antisera. This approach can be extended to examine the antigenic landscape in patient sera to facilitate investigation of the immune response to NoV. IMPORTANCE NoV infections are a leading cause of gastroenteritis in the United States. Human NoVs exhibit extensive genetic and antigenic diversity, which makes it challenging to design a vaccine that provides broad protection against infection. Antibodies developed during the immune response play an important role in the control of NoV infections. Neutralizing antibodies that act by sterically blocking the site on the virus used to bind human cells have been identified. Identification of other antibody binding sites associated with virus neutralization is therefore of interest. Here, we use a high-resolution method to map multiple antibody binding sites simultaneously from complex serum samples. The results show that a relatively small number of sites on the virus bind a large number of independently generated antibodies, suggesting that immunodominance plays a role in the humoral immune response to NoV infections.

Monoclonal antibodies and their target specificity against SARS-CoV-2 infections: Perspectives and challenges Short title: Monoclonal antibodies and SARS-CoV-2 infections

2022 ◽  
Vol 16 ◽  
Author(s):  
Mohammed Ali Bakkari ◽  
Sivakumar Sivagurunathan Moni ◽  
Muhammad Hadi Sultan ◽  
Osama A. Madkhali
Keyword(s):  
Monoclonal Antibodies ◽  
Virus Infection ◽  
Neutralizing Antibodies ◽  
Cell Function ◽  
Therapeutic Index ◽  
Spike Protein ◽  
Virus Infectivity ◽  
Antigen Specificity ◽  
Cytokine Network ◽  
Frequent Mutations

Abstract: The world continues to be in the midst of a distressing pandemic of coronavirus disease 2019 (COVID-19) infection caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), a novel virus with multiple antigenic systems. The virus enters via nasopharynx, oral and infects cells by the expression of the spike protein, and enters the lungs using the angiotensin-converting enzyme-2 receptor. The spectrum of specific immune responses to SARS-CoV-2 virus infection is increasingly challenging as frequent mutations have been reported and their antigen specificity varies accordingly. The development of monoclonal antibodies (mAbs) will have a more significant advantage in suppressing SARS-CoV-2 virus infectivity. Recently, mAbs have been developed to target specific neutralizing antibodies against SARS-CoV-2 infection. The use of the therapeutic index of mAbs that can elicit neutralization by binding to the viral spike protein and suppress the cytokine network is a classic therapeutic approach for a potential cure. The development of mAbs against B-cell function as well as inhibition of the cytokine network has also been a focus in recent research. Recent studies have demonstrated the efficacy of mAbs as antibody cocktail preparations against SARS-CoV-2 infection. Target specific therapeutic accomplishment with mAbs, a milestone in the modern therapeutic age, can be used to achieve a specific therapeutic strategy to suppress SARS-CoV-2 virus infection. This review focuses on the molecular aspects of the cytokine network and antibody formation to better understand the development of mAbs against SARS-CoV-2 infection.

scholarly journals Escape from neutralizing antibodies by SARS-CoV-2 spike protein variants

2020 ◽  
Author(s):  
Yiska Weisblum ◽  
Fabian Schmidt ◽  
Fengwen Zhang ◽  
Justin DaSilva ◽  
Daniel Poston ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Reporter Virus ◽  
Low Frequencies ◽  
Protein Variants ◽  
Prior Infection ◽  
Neutralizing Epitopes

AbstractNeutralizing antibodies elicited by prior infection or vaccination are likely to be key for future protection of individuals and populations against SARS-CoV-2. Moreover, passively administered antibodies are among the most promising therapeutic and prophylactic anti-SARS-CoV-2 agents. However, the degree to which SARS-CoV-2 will adapt to evade neutralizing antibodies is unclear. Using a recombinant chimeric VSV/SARS-CoV-2 reporter virus, we show that functional SARS-CoV-2 S protein variants with mutations in the receptor binding domain (RBD) and N-terminal domain that confer resistance to monoclonal antibodies or convalescent plasma can be readily selected. Notably, SARS-CoV-2 S variants that resist commonly elicited neutralizing antibodies are now present at low frequencies in circulating SARS-CoV-2 populations. Finally, the emergence of antibody-resistant SARS-CoV-2 variants that might limit the therapeutic usefulness of monoclonal antibodies can be mitigated by the use of antibody combinations that target distinct neutralizing epitopes.

scholarly journals α-Hemolysin-Aided Oligomerization of the Spike Protein RBD Resulted in Improved Immunogenicity and Neutralization Against SARS-CoV-2 Variants

2021 ◽  
Vol 12 ◽  
Author(s):  
Jintao Zou ◽  
Haiming Jing ◽  
Xiaoli Zhang ◽  
Yiheng Liu ◽  
Zhuo Zhao ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Neutralization Assay ◽  
Spike Protein ◽  
Wild Type Virus ◽  
Carrier Protein ◽  
Specific Antibodies ◽  
Linear Epitopes ◽  
Cellular Immune ◽  
Candidate Antigen

The increase in confirmed COVID-19 cases and SARS-CoV-2 variants calls for the development of safe and broad cross-protective vaccines. The RBD of the spike protein was considered to be a safe and effective candidate antigen. However, the low immunogenicity limited its application in vaccine development. Herein, we designed and obtained an RBD heptamer (mHla-RBD) based on a carrier protein-aided assembly strategy. The molecular weight of mHla-RBD is up to 450 kDa, approximately 10 times higher than that of the RBD monomer. When formulated with alum adjuvant, mHla-RBD immunization significantly increased the immunogenicity of RBD, as indicated by increased titers of RBD-specific antibodies, neutralizing antibodies, Th2 cellular immune response, and pseudovirus neutralization activity, when compared to RBD monomer. Furthermore, we confirmed that RBD-specific antibodies predominantly target conformational epitopes, which was approximately 200 times that targeting linear epitopes. Finally, a pseudovirus neutralization assay revealed that neutralizing antibodies induced by mHla-RBD against different SARS-CoV-2 variants were comparable to those against the wild-type virus and showed broad-spectrum neutralizing activity toward different SARS-CoV-2 variants. Our results demonstrated that mHla-RBD is a promising candidate antigen for development of SARS-CoV-2 vaccines and the mHla could serve as a universal carrier protein for antigen design.

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