scholarly journals Neutralizing Antibodies to SARS‐CoV‐2 Selected from a Human Antibody Library Constructed Decades Ago

2021 ◽  
pp. 2102181
Author(s):  
Min Qiang ◽  
Peixiang Ma ◽  
Yu Li ◽  
Hejun Liu ◽  
Adam Harding ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Human Antibody ◽  
Antibody Library

scholarly journals Potent SARS-CoV-2 neutralizing antibodies selected from a human antibody library constructed decades ago

2020 ◽  
Author(s):  
Min Qiang ◽  
Peixiang Ma ◽  
Yu Li ◽  
Hejun Liu ◽  
Adam Harding ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Somatic Hypermutation ◽  
Human Antibody ◽  
Antibody Library ◽  
Origin And Evolution ◽  
The Public ◽  
History Of ◽  
Antibody Discovery ◽  
Antibody Libraries ◽  
Public Health Challenge

ABSTRACTCombinatorial antibody libraries not only effectively reduce antibody discovery to a numbers game, but enable documentation of the history of antibody responses in an individual. The SARS-CoV-2 pandemic has prompted a wider application of this technology to meet the public health challenge of pandemic threats in the modern era. Herein, we used a combinatorial human antibody library constructed 20 years before the COVID-19 pandemic to discover three highly potent antibodies that selectively bind SARS-CoV-2 spike protein and neutralize authentic SARS-CoV-2 virus. Compared to neutralizing antibodies from COVID-19 patients with generally low somatic hypermutation (SHM), these antibodies contain over 13-22 SHMs, many of which are involved in specific interactions in crystal structures with SARS-CoV-2 spike RBD. The identification of these somatically mutated antibodies in a pre-pandemic library raises intriguing questions about the origin and evolution of human immune responses to SARS-CoV-2.

scholarly journals Unique structural solution from a VH3-30 antibody targeting the hemagglutinin stem of influenza A viruses

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wayne D. Harshbarger ◽  
Derrick Deming ◽  
Gordon J. Lockbaum ◽  
Nattapol Attatippaholkun ◽  
Maliwan Kamkaew ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Influenza A ◽  
Critical Role ◽  
Binding Activity ◽  
Human Antibody ◽  
Broadly Neutralizing Antibodies ◽  
Influenza A Viruses ◽  
Universal Vaccine ◽  
Structural Details ◽  
Structural Solution

AbstractBroadly neutralizing antibodies (bnAbs) targeting conserved influenza A virus (IAV) hemagglutinin (HA) epitopes can provide valuable information for accelerating universal vaccine designs. Here, we report structural details for heterosubtypic recognition of HA from circulating and emerging IAVs by the human antibody 3I14. Somatic hypermutations play a critical role in shaping the HCDR3, which alone and uniquely among VH3-30 derived antibodies, forms contacts with five sub-pockets within the HA-stem hydrophobic groove. 3I14 light-chain interactions are also key for binding HA and contribute a large buried surface area spanning two HA protomers. Comparison of 3I14 to bnAbs from several defined classes provide insights to the bias selection of VH3-30 antibodies and reveals that 3I14 represents a novel structural solution within the VH3-30 repertoire. The structures reported here improve our understanding of cross-group heterosubtypic binding activity, providing the basis for advancing immunogen designs aimed at eliciting a broadly protective response to IAV.

scholarly journals A glycoside analog of mammalian oligomannose formulated with a TLR4-stimulating adjuvant elicits HIV-1 cross-reactive antibodies

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jean-François Bruxelle ◽  
Tess Kirilenko ◽  
Nino Trattnig ◽  
Yiqiu Yang ◽  
Matteo Cattin ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Envelope Protein ◽  
Protein Sequence ◽  
Neutralizing Antibodies ◽  
Human Antibody ◽  
Broadly Neutralizing Antibodies ◽  
Specific Antibodies ◽  
Strong Binding ◽  
Hiv Envelope ◽  
Hiv 1

AbstractThe occurrence of oligomannose-specific broadly neutralizing antibodies (bnAbs) has spurred efforts to develop immunogens that can elicit similar antibodies. Here, we report on the antigenicity and immunogenicity of a CRM197-conjugate of a previously reported oligomannose mimetic. Oligomannose-specific bnAbs that are less dependent on interactions with the HIV envelope protein sequence showed strong binding to the glycoconjugates, with affinities approximating those reported for their cognate epitope. The glycoconjugate is also recognized by inferred germline precursors of oligomannose-specific bnAbs, albeit with the expected low avidity, supporting its potential as an immunogen. Immunization of human-antibody transgenic mice revealed that only a TLR4-stimulating adjuvant formulation resulted in antibodies able to bind a panel of recombinant HIV trimers. These antibodies bound at relatively modest levels, possibly explaining their inability to neutralize HIV infectivity. Nevertheless, these findings contribute further to understanding conditions for eliciting HIV-cross-reactive oligomannose-specific antibodies and inform on next steps for improving on the elicited response.

ANALYSIS OF BIOLOGICAL FUNCTION OF ANTI EGFR ANTIBODIES ISOLATED FROM SCREENING OF HUMAN ANTIBODY LIBRARY SPECIFIC TO HUMAN RCC

2009 ◽  
Vol 181 (4S) ◽  
pp. 157-157
Author(s):  
Noriko Sato ◽  
Ryoichi Shiroki ◽  
Gene Kurosawa ◽  
Susumu Tsutsumi ◽  
Yasushi Akahori ◽  
...  
Keyword(s):  
Biological Function ◽  
Human Antibody ◽  
Antibody Library

scholarly journals Dissecting Human Antibody Responses: Useful, Basic, and Surprising Findings

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. SCI-49-SCI-49
Author(s):  
Antonio Lanzavecchia
Keyword(s):  
B Cell ◽  
Dna Sequences ◽  
Neutralizing Antibodies ◽  
Influenza A ◽  
Somatic Mutations ◽  
Vaccine Design ◽  
Human Memory ◽  
Affinity Maturation ◽  
Effective Vaccine ◽  
Human Antibody

Abstract We use cell culture-based high-throughput methods to interrogate human memory B cell and plasma cell repertoires and to isolate antibodies selected on the basis of their neutralizing potency and breadth. Relevant examples are antibodies that neutralize all influenza A viruses or even four paramyxoviruses. By targeting conserved structures, these broadly neutralizing antibodies are less prone to select escape mutants and are promising candidates for prophylaxis and therapy of infections, as well as tools for vaccine design. The value of a target-agnostic approach to vaccine design is illustrated by our discovery of extremely potent antibodies that neutralize human cytomegalovirus, which led to the identification of their viral ligand, a pentameric complex that was then produced and tested as an effective vaccine. By reconstructing the genealogy trees of specific B cell clones, we investigate the role of somatic mutations in affinity maturation and in generation of antibody variants with broader or different specificity. Somatic mutations can also generate autoantibodies, as found in patients with pemphigus and autoimmune pulmonary alveolar proteinosis. Recently, while searching for antibodies that broadly react with malaria variant antigens, we discovered a new mechanism of antibody diversification, which relies on templated insertions of genomic DNA sequences into immunoglobulin genes, followed by somatic mutations. Disclosures Lanzavecchia: Humabs SA: Equity Ownership, Research Funding.

scholarly journals Influenza Virus Resistance to Human Neutralizing Antibodies

mBio ◽  
2012 ◽  
Vol 3 (4) ◽  
Author(s):  
James E. Crowe
Keyword(s):  
Influenza Virus ◽  
B Cell ◽  
Neutralizing Antibodies ◽  
Cell Receptor ◽  
B Cell Receptor ◽  
Influenza Viruses ◽  
Surface Proteins ◽  
Progeny Virus ◽  
Human Antibody ◽  
Functional Surface

ABSTRACT The human antibody repertoire has an exceptionally large capacity to recognize new or changing antigens through combinatorial and junctional diversity established at the time of V(D)J recombination and through somatic hypermutation. Influenza viruses exhibit a relentless capacity to escape the human antibody response by altering the amino acids of their surface proteins in hypervariable domains that exhibit a high level of structural plasticity. Both parties in this high-stakes game of shape shifting drive structural evolution of their functional proteins (the B cell receptor/antibody on one side and the viral hemagglutinin and neuraminidase proteins on the other) using error-prone polymerase systems. It is likely that most of the genetic mutations that occur in these systems are deleterious, resulting in the failure of the B cell or virus with mutations to propagate in the immune repertoire or viral quasispecies. A subset of mutations is tolerated in functional surface proteins that enter the B cell or virus progeny pool. In both cases, selection occurs in the population of mutated and unmutated species. In cases where the functional avidity of the B cell receptor is increased significantly, that clone may be selected for preferential expansion. In contrast, an influenza virus that “escapes” the inhibitory effect of secreted antibodies may represent a high proportion of the progeny virus in that host. The recent paper by O’Donnell et al. [C. D. O’Donnell et al., mBio 3(3):e00120-12, 2012] identifies a mechanism for antibody resistance that does not require escape from binding but rather achieves a greater efficiency in replication.

Construction of immune human library and screening of neutralizing antibodies specific to glycoprotein of severe fever with thrombocytopenia syndrome virus

2020 ◽  
Author(s):  
wenshuai zhang ◽  
Xiling Guo ◽  
Ying Chi ◽  
Yongjun Jiao
Keyword(s):  
Neutralizing Antibodies ◽  
High Capacity ◽  
Binding Activity ◽  
Immunofluorescence Assay ◽  
Antibody Library ◽  
Phage Display Technology ◽  
Glycoprotein C ◽  
Human Scfv ◽  
Display Technology ◽  
Severe Fever

Abstract Background Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease circulated in eastern Asian countries including China, Japan and South Korea. Currently, there are no effective prophylactic or therapeutic measurements available in the clinical settings. Antibody-mediated prevention and treatment can be an effective complement to the clinical supporting strategies. Glycoprotein N (Gn) and Glycoprotein C (Gc) are two of the highly antigenic envelope proteins on the SFTS virus (SFTSV) surface and contain neutralizing epitopes that can induce neutralizing antibodies. Methods To obtain the neutralizing antibodies specific to glycoprotein of SFTSV, we used phage display technology to generate a human phage antibody library with ScFv format from the peripheral lymphocytes of 8 patients who had recovered from SFTS. The library was bio-panned against recombinant Gn and Gc proteins for four rounds to find their specific antibody clones. Finally, the selected clones were characterized by binding activity test, virus neutralization and Competitive ELISA.Results An immune human ScFv antibody library against SFTSV with high capacity and diversity was constructed. After 4 rounds of panning, 6 distinct clones were found. Of them, 5 were specific to Gn, whereas only 1 was specific to Gc. The immunofluorescence assay showed only three clones with Gn specificity called MAb 4A6, MAb 2B6 and MAb 1F2, respectively, could bind nature virion. All these clones showed broad neutralization activity against the SFTSV, and had different antigenic epitopes from MAb 4-5, a previous identified antibody clone. Conclusions Three new monoclonal antibodies described in our study could be used as potential agents in immunotherapy against SFTSV infection.

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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