Biology subjects

Doranz, B.

Publications and source records attributed to Doranz, B..

4 recordsLinked to original sources

bioRxiv2021

Neutralizing and protective human monoclonal antibodies recognizing the N-terminaldomain of the SARS-CoV-2 spike protein

Most human monoclonal antibodies (mAbs) neutralizing SARS-CoV-2 recognize the spike (S) protein receptor-binding domain and block virus interactions with the cellular receptor angiotensin-converting enzyme 2. We describe a panel of human mAbs binding to diverse epitopes on the N-terminal domain (NTD) of S protein from SARS-CoV-2 convalescent donors and found a minority of these possessed neutralizing activity. Two mAbs (COV2-2676 and COV2-2489) inhibited infection of authentic SARS-CoV-2 and recombinant VSV/SARS-CoV-2 viruses. We mapped their binding epitopes by alanine-scanning mutagenesis and selection of functional SARS-CoV-2 S neutralization escape variants. Mechanistic studies showed that these antibodies neutralize in part by inhibiting a post-attachment step in the infection cycle. COV2-2676 and COV2-2489 offered protection either as prophylaxis or therapy, and Fc effector functions were required for optimal protection. Thus, natural infection induces a subset of potent NTD-specific mAbs that leverage neutralizing and Fc-mediated activities to protect against SARS-CoV-2 infection using multiple functional attributes.

immunology↗

bioRxiv2020

Convergence of a common solution to broad ebolavirus neutralization by glycan cap directed human antibodies

Antibodies that target the glycan cap epitope on ebolavirus glycoprotein (GP) are common in the adaptive response of survivors. A subset is known to be broadly neutralizing, but the details of their epitopes and basis for neutralization is not well-understood. Here we present cryo-electron microscopy (cryo-EM) structures of several glycan cap antibodies that variably synergize with GP base-binding antibodies. These structures describe a conserved site of vulnerability that anchors the mucin-like domains (MLD) to the glycan cap, which we name the MLD-anchor and cradle. Antibodies that bind to the MLD-cradle share common features, including the use of IGHV1-69 and IGHJ6 germline genes, which exploit hydrophobic residues and form beta-hairpin structures to mimic the MLD-anchor, disrupt MLD attachment, destabilize GP quaternary structure and block cleavage events required for receptor binding. Our results collectively provide a molecular basis for ebolavirus neutralization by broadly reactive glycan cap antibodies.

immunology↗

bioRxiv2020

An affinity-matured human monoclonal antibody targeting fusion loop epitope of dengue virus with in vivo therapeutic potency

Dengue virus (DENV), from the genus flavivirus of the family flaviviridae, causes serious health problems globally. Human monoclonal antibodies (HuMAb) can be used to elucidate the mechanisms of neutralization and antibody-dependent enhancement (ADE) of DENV infections, leading to the development of a vaccine or therapeutic antibodies. Here, we generated eight HuMAb clones from an Indonesian patient infected with DENV. These HuMAbs exhibited the typical characteristics of weak neutralizing antibodies including high cross-reactivity with other flaviviruses and targeting of the fusion loop epitope (FLE). However, one of the HuMAbs, 3G9, exhibited strong neutralization ability (NT50 < 0.1 {micro}g/ml) and possessed a high somatic hyper-mutation rate of the variable region, indicating affinity-maturation. Administration of this antibody significantly improved the survival rate of interferon-/{beta}/{gamma} receptor knockout C57BL/6 mice after a lethal DENV challenge. Additionally, Fc-modified 3G9 molecules that had lost their in vitro ADE activity showed significantly enhanced therapeutic potency in vivo and competed strongly with an ADE-prone antibody in vitro. Taken together, the affinity-matured FLE-targeting antibody 3G9 exhibits several promising features for therapeutic application including a low NT50 value, potential for pan-flavivirus infection treatment, and suppression of ADE. This study demonstrates the therapeutic potency of affinity-matured FLE-targeting antibodies.

microbiology↗

bioRxiv2020

Integrated technology platform for accelerated discovery of antiviral antibody therapeutics

The emergence and reemergence of highly virulent viral pathogens with pandemic potential has created an urgent need for accelerated discovery of antiviral therapeutics. Antiviral human monoclonal (mAbs) are promising drug candidates to prevent or treat severe viral diseases, but the long timelines needed for discovery limits their rapid deployment and use. Here, we report the development of an integrated sequence of technologies incorporating advances in single-cell mRNA sequence analysis, bioinformatics, synthetic biology, and high-throughput functional analysis that allowed us to discover highly potent antiviral human mAbs and validate their activity in vivo at an unprecedented scale, speed, and efficiency. In a 78-day study, modeling deployment of a rapid response platform to an outbreak, we isolated >100 individual Zika virus (ZIKV) specific human mAbs, assessed their function, identified 29 broadly-neutralizing mAbs, and verified therapeutic potency of lead candidates with antibody-encoding mRNA formulation and/or IgG protein delivery in mice and nonhuman primates. Our work provides a roadmap for the rapid antibody discovery programs against viral pathogens of global concern.

immunology↗