Isolation of human antibodies against influenza B neuraminidase and mechanisms of protection at the airway interface.

Influenza B viruses (IBVs) comprise a substantial portion of the circulating seasonal human influenza viruses. Here, we describe the isolation of human monoclonal antibodies (mAbs) that recognized the IBV neuraminidase (NA) glycoprotein from an individual following seasonal vaccination. Competition-binding experiments suggested the antibodies recognized two major antigenic sites.

Anti-Ebola virus mAb 3A6 with unprecedented potency protects highly viremic animals from fatal outcome and physically lifts its glycoprotein target from the virion membrane.

Monoclonal antibodies (mAbs) against Ebola virus (EBOV) glycoprotein (GP) are the standard of care for Ebola virus disease (EVD). Anti-GP mAbs targeting the stalk and membrane proximal external region (MPER) potently neutralize EBOV . However, their neutralization mechanism is poorly understood because they target a GP epitope that has evaded structural characterization.

Breaking barriers in antibody discovery: harnessing divergent species for accessing difficult and conserved drug targets.

To exploit highly conserved and difficult drug targets, including multipass membrane proteins, monoclonal antibody discovery efforts increasingly rely on the advantages offered by divergent species such as rabbits, camelids, and chickens. Here, we provide an overview of antibody discovery technologies, analyze gaps in therapeutic antibodies that stem from the historic use of mice, and examine opportunities to exploit previously inaccessible targets through discovery now possible in alternate species. We summarize the clinical development of antibodies raised from divergent species, discussing how these animals enable robust immune responses against highly conserved binding sites and yield antibodies capable of penetrating functional pockets via long HCDR3 regions.

Single B cell transcriptomics identifies multiple isotypes of broadly neutralizing antibodies against flaviviruses.

Sequential dengue virus (DENV) infections often generate neutralizing antibodies against all four DENV serotypes and sometimes, Zika virus. Characterizing cross-flavivirus broadly neutralizing antibody (bnAb) responses can inform countermeasures that avoid enhancement of infection associated with non-neutralizing antibodies. Here, we used single cell transcriptomics to mine the bnAb repertoire following repeated DENV infections.

Zika-specific neutralizing antibodies targeting inter-dimer envelope epitopes.

Zika virus (ZIKV) is an emerging pathogen that causes devastating congenital defects. The overlapping epidemiology and immunologic cross-reactivity between ZIKV and dengue virus (DENV) pose complex challenges to vaccine design, given the potential for antibody-dependent enhancement of disease. Therefore, classification of ZIKV-specific antibody targets is of notable value.

Single B cell transcriptomics identifies multiple isotypes of broadly neutralizing antibodies against flaviviruses.

Sequential dengue virus (DENV) infections often generate neutralizing antibodies against all four DENV serotypes and sometimes, Zika virus. Characterizing cross-flavivirus broadly neutralizing antibody (bnAb) responses can inform countermeasure strategies that avoid infection enhancement associated with non-neutralizing antibodies. Here, we used single cell transcriptomics to mine the bnAb repertoire following secondary DENV infection.

Shark nanobodies with potent SARS-CoV-2 neutralizing activity and broad sarbecovirus reactivity.

Despite rapid and ongoing vaccine and therapeutic development, SARS-CoV-2 continues to evolve and evade, presenting a need for next-generation diverse therapeutic modalities. Here we show that nurse sharks immunized with SARS-CoV-2 recombinant receptor binding domain (RBD), RBD-ferritin (RFN), or spike protein ferritin nanoparticle (SpFN) immunogens elicit a set of new antigen receptor antibody (IgNAR) molecules that target two non-overlapping conserved epitopes on the spike RBD. Representative shark antibody variable NAR-Fc chimeras (ShAbs) targeting either of the two epitopes mediate cell-effector functions, with high affinity to all SARS-CoV-2 viral variants of concern, including the divergent Omicron strains.

Antibody specificity against highly conserved membrane protein Claudin 6 driven by single atomic contact point.

The tight junction protein claudin 6 (CLDN6) is differentially expressed on cancer cells with almost no expression in healthy tissue. However, achieving therapeutic MAb specificity for this 4 transmembrane protein is challenging because it is nearly identical to the widely expressed CLDN9, with only 3 extracellular amino acids different. Most other CLDN6 MAbs, including those in clinical development are cross-reactive with CLDN9, and several trials have now been stopped.

Rare, convergent antibodies targeting the stem helix broadly neutralize diverse betacoronaviruses.

Humanity has faced three recent outbreaks of novel betacoronaviruses, emphasizing the need to develop approaches that broadly target coronaviruses. Here, we identify 55 monoclonal antibodies from COVID-19 convalescent donors that bind diverse betacoronavirus spike proteins. Most antibodies targeted an S2 epitope that included the K814 residue and were non-neutralizing.

Sites of vulnerability in HCV E1E2 identified by comprehensive functional screening.

The E1 and E2 envelope proteins of hepatitis C virus (HCV) form a heterodimer that drives virus-host membrane fusion. Here, we analyze the role of each amino acid in E1E2 function, expressing 545 individual alanine mutants of E1E2 in human cells, incorporating them into infectious viral pseudoparticles, and testing them against 37 different monoclonal antibodies (MAbs) to ascertain full-length translation, folding, heterodimer assembly, CD81 binding, viral pseudoparticle incorporation, and infectivity. We propose a model describing the role of each critical residue in E1E2 functionality and use it to examine how MAbs neutralize infection by exploiting functionally critical sites of vulnerability on E1E2.

Somatic Hypermutation and Framework Mutations of Variable Region Contribute to Anti-Zika Virus-Specific Monoclonal Antibody Binding and Function.

Zika virus (ZIKV) is a global public health concern due to its ability to cause congenital Zika syndrome and lack of approved vaccine, therapeutic, or other control measures. We discovered eight novel rabbit monoclonal antibodies (MAbs) that bind to distinct ZIKV envelope protein epitopes. The majority of the MAbs were ZIKV specific and targeted the lateral ridge of the envelope (E) protein domain III, while the MAb with the highest neutralizing activity recognized a putative quaternary epitope spanning E protein domains I and III.

An antibody targeting the N-terminal domain of SARS-CoV-2 disrupts the spike trimer.

The protective human antibody response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) focuses on the spike (S) protein, which decorates the virion surface and mediates cell binding and entry. Most SARS-CoV-2 protective antibodies target the receptor-binding domain or a single dominant epitope ("supersite") on the N-terminal domain (NTD). Using the single B cell technology called linking B cell receptor to antigen specificity through sequencing (LIBRA-Seq), we isolated a large panel of NTD-reactive and SARS-CoV-2-neutralizing antibodies from an individual who had recovered from COVID-19.

Rapid discovery of diverse neutralizing SARS-CoV-2 antibodies from large-scale synthetic phage libraries.

Coronavirus disease 2019 (COVID-19) is an evolving global public health crisis in need of therapeutic options. Passive immunization of monoclonal antibodies (mAbs) represents a promising therapeutic strategy capable of conferring immediate protection from SARS-CoV-2 infection. Herein, we describe the discovery and characterization of neutralizing SARS-CoV-2 IgG and VHH antibodies from four large-scale phage libraries.

Exposing cryptic epitopes on the Venezuelan equine encephalitis virus E1 glycoprotein prior to treatment with alphavirus cross-reactive monoclonal antibody allows blockage of replication early in infection.

Eastern equine encephalitis virus (EEEV), western equine encephalitis virus (WEEV) and Venezuelan equine encephalitis virus (VEEV) can cause fatal encephalitis in humans and equids. Some MAbs to the E1 glycoprotein are known to be cross-reactive, weakly neutralizing in vitro but can protect from disease in animal models. We investigated the mechanism of neutralization of VEEV infection by the broadly cross-reactive E1-specific MAb 1A4B-6.

Potent neutralization of SARS-CoV-2 variants of concern by an antibody with an uncommon genetic signature and structural mode of spike recognition.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineages that are more transmissible and resistant to currently approved antibody therapies poses a considerable challenge to the clinical treatment of coronavirus disease (COVID-19). Therefore, the need for ongoing discovery efforts to identify broadly reactive monoclonal antibodies to SARS-CoV-2 is of utmost importance. Here, we report a panel of SARS-CoV-2 antibodies isolated using the linking B cell receptor to antigen specificity through sequencing (LIBRA-seq) technology from an individual who recovered from COVID-19.

Therapeutic alphavirus cross-reactive E1 human antibodies inhibit viral egress.

Alphaviruses cause severe arthritogenic or encephalitic disease. The E1 structural glycoprotein is highly conserved in these viruses and mediates viral fusion with host cells. However, the role of antibody responses to the E1 protein in immunity is poorly understood.

Pan-protective anti-alphavirus human antibodies target a conserved E1 protein epitope.

Alphaviruses are emerging, mosquito-transmitted pathogens that cause musculoskeletal and neurological disease in humans. Although neutralizing antibodies that inhibit individual alphaviruses have been described, broadly reactive antibodies that protect against both arthritogenic and encephalitic alphaviruses have not been reported. Here, we identify DC2.

Convergent antibody responses to the SARS-CoV-2 spike protein in convalescent and vaccinated individuals.

Unrelated individuals can produce genetically similar clones of antibodies, known as public clonotypes, which have been seen in responses to different infectious diseases, as well as healthy individuals. Here we identify 37 public clonotypes in memory B cells from convalescent survivors of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or in plasmablasts from an individual after vaccination with mRNA-encoded spike protein. We identify 29 public clonotypes, including clones recognizing the receptor-binding domain (RBD) in the spike protein S1 subunit (including a neutralizing, angiotensin-converting enzyme 2 [ACE2]-blocking clone that protects in vivo) and others recognizing non-RBD epitopes that bind the S2 domain.