Profiling a large HIV-1 elite neutralizer cohort reveals remarkable CD4bs bNAb for HIV-1 prevention and therapy.

Administration of HIV-1 neutralizing antibodies can suppress viremia and prevent infection . However, clinical use is challenged by broad envelope sequence diversity and rapid emergence of viral escape . Here, we performed single B cell profiling of 32 top HIV-1 elite neutralizers to identify broadly neutralizing antibodies (bNAbs) with highest potency and breadth for clinical application.

Determinants of human versus mosquito cell entry by the Chikungunya virus envelope proteins.

Chikungunya virus (CHIKV) infects both humans and mosquitoes during its transmission cycle. How the virus's envelope proteins mediate entry in cells from such different species is unclear. MXRA8 is a receptor for CHIKV in mammalian cells, but the receptor(s) in mosquito cells remains unknown.

Spike mutations that affect the function and antigenicity of recent KP.3.1.1-like SARS-CoV-2 variants.

SARS-CoV-2 is under strong evolutionary selection to acquire mutations in its spike protein that reduce neutralization by human polyclonal antibodies. Here we use pseudovirus-based deep mutational scanning to measure how mutations to the spike from the recent KP.3.

Fostemsavir analog BMS-818251 has enhanced viral neutralization potency and similar escape mutation profile.

BMS-818251, a fostemsavir analog, is a next-generation HIV-1 attachment inhibitor with enhanced potency and a similar resistance profile. By using viral outgrowth assays with HIV+ donor samples, we demonstrate here that BMS-818251 exhibits superior viral suppression compared to temsavir, the active form of fostemsavir. To map potential resistance pathways, we employed deep mutational scanning and pseudotyped virus neutralization assays to identify escape mutations within the HIV-1 envelope glycoprotein (Env).

Stabilization of H5 highly pathogenic avian influenza hemagglutinin improves vaccine-elicited neutralizing antibody responses.

Transmission of highly pathogenic avian influenza from H5 clade 2.3.4.

Replaying germinal center evolution on a quantified affinity landscape.

Darwinian evolution of immunoglobulin genes within germinal centers (GC) underlies the progressive increase in antibody affinity following antigen exposure. Whereas the mechanics of how competition between GC B cells drives increased affinity are well established, the dynamical evolutionary features of this process remain poorly characterized. We devised an experimental evolution model in which we "replay" over one hundred instances of a clonally homogenous GC reaction and follow the selective process by assigning affinities to all cells using deep mutational scanning.

Loss of FCoV-23 spike domain 0 enhances fusogenicity and entry kinetics.

The ability of coronaviruses to recombine and cross species barriers affects human and animal health globally and is a pandemic threat. FCoV-23 is a recently emerged, highly pathogenic recombinant coronavirus responsible for a widespread outbreak of feline infectious peritonitis. Here we report cryogenic electron microscopy structures of two FCoV-23 spike isoforms that correspond to the in-host loss of domain 0 observed in clinical samples.

RSV F evolution escapes some monoclonal antibodies but does not strongly erode neutralization by human polyclonal sera.

Vaccines and monoclonal antibodies targeting the respiratory syncytial virus (RSV) fusion protein (F) have recently begun to be widely used to protect infants and high-risk adults. Some other viral proteins evolve to erode polyclonal antibody neutralization and escape individual monoclonal antibodies. However, the impact of RSV F evolution on antibody neutralization is not yet thoroughly understood.

The mutation rate of SARS-CoV-2 is highly variable between sites and is influenced by sequence context, genomic region, and RNA structure.

RNA viruses like SARS-CoV-2 have high mutation rates, which contribute to their rapid evolution. Mutation rates depend on mutation type and can vary between sites in a virus's genome. Understanding this variation can shed light on the mutational processes at play, and is crucial for quantitative modeling of viral evolution.

The Data are Insufficient to Confidently Root the SARS-CoV-2 Phylogenetic Tree.

Several years ago, I published a paper that described the discrepancy between outgroup and date-based methods for rooting the SARS-CoV-2 phylogenetic tree, and proposed the discrepancy could arise from biases among the available early viral sequences. Here, I explain why the root remains uncertain, including via an interactive narrative at https://nextstrain.org/groups/jbloomlab/narratives/SARS2-rooting/early-SARS2-trees-v1 that enables the reader to examine the underlying data and understand discrepancies that lead different methods to reach different inferences about the root.

Pleiotropic mutational effects on function and stability constrain the antigenic evolution of influenza hemagglutinin.

The evolution of human influenza virus hemagglutinin (HA) involves simultaneous selection to acquire antigenic mutations that escape population immunity while preserving protein function and stability. Epistasis shapes this evolution, as an antigenic mutation that is deleterious in one genetic background may become tolerated in another. However, the extent to which epistasis can alleviate pleiotropic conflicts between immune escape and protein function/stability is unclear.

Deep mutational scanning of rabies glycoprotein defines mutational constraint and antibody-escape mutations.

Rabies virus causes nearly 60,000 human deaths annually. Antibodies that target the rabies glycoprotein (G) are being developed as post-exposure prophylactics, but mutations in G can render such antibodies ineffective. Here, we use pseudovirus deep mutational scanning to measure how all single-amino-acid mutations to G affect cell entry and neutralization by a panel of antibodies.

A broad antibody with enhanced HIV-1 neutralization via bispecific antibody-mediated prepositioning.

Antibodies targeting the highly conserved prehairpin intermediate (PHI) of class I viral membrane-fusion proteins are generally weakly neutralizing and are not considered viable therapeutic agents. We previously demonstrated that antibodies targeting the gp41 N-heptad repeat (NHR), which is transiently exposed in the HIV-1 PHI, exhibit enhanced broad neutralization in cells expressing the Fc receptor, FcγRI. To enhance neutralization in cells lacking FcγRI, we here develop a bispecific antibody (bsAb) by fusing an NHR-targeting antibody to an antibody against CD4, the HIV-1 receptor on T cells.

Comprehensive maps of escape mutations from antibodies 10-1074 and 3BNC117 for Envs from two divergent HIV strains.

Antibodies capable of neutralizing many strains of HIV are being explored as prophylactic and therapeutic agents, but viral escape mutations pose a major challenge. Efforts have been made to experimentally define the escape mutations from specific antibodies in specific viral strains, but it remains unclear how much the effects of mutations on neutralization differ among HIV strains. Here, we use pseudovirus deep mutational scanning to comprehensively map escape mutations from the V3 loop targeting antibody 10-1074 and the CD4-binding site targeting antibody 3BNC117 for both a clade A (BF520) and a clade B (TRO.

RSV F evolution escapes some monoclonal antibodies but does not strongly erode neutralization by human polyclonal sera.

Vaccines and monoclonal antibodies targeting the respiratory syncytial virus (RSV) fusion protein (F) have recently begun to be widely used to protect infants and high-risk adults. Some other viral proteins evolve to erode polyclonal antibody neutralization and escape individual monoclonal antibodies. However, little is known about how RSV F evolution affects antibodies.

High-throughput neutralization measurements correlate strongly with evolutionary success of human influenza strains.

Human influenza viruses rapidly acquire mutations in their hemagglutinin (HA) protein that erode neutralization by antibodies from prior exposures. Here, we use a sequencing-based assay to measure neutralization titers for 78 recent H3N2 HA strains against a large set of children and adult sera, measuring ~10,000 total titers. There is substantial person-to-person heterogeneity in the titers against different viral strains, both within and across age cohorts.

Functional and antigenic landscape of the Nipah virus receptor-binding protein.

Nipah virus recurrently spills over to humans, causing fatal infections. The viral receptor-binding protein (RBP or G) attaches to host receptors and is a major target of neutralizing antibodies. Here, we use deep mutational scanning to measure how all amino-acid mutations to the RBP affect cell entry, receptor binding, and escape from neutralizing antibodies.

SARS-CoV-2 neutralizing antibody specificities differ dramatically between recently infected infants and immune-imprinted individuals.

The immune response to viral infection is shaped by past exposures to related virus strains, a phenomenon known as imprinting. For severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), much of the population has been imprinted by a viral spike from an early strain, either through vaccination or infection during the early stages of the COVID-19 pandemic. As a consequence of this imprinting, infection with more recent SARS-CoV-2 strains primarily boosts cross-reactive antibodies elicited by the imprinting strain.

Bispecific antibodies targeting the N-terminal and receptor binding domains potently neutralize SARS-CoV-2 variants of concern.

The ongoing emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) that reduce the effectiveness of antibody therapeutics necessitates development of next-generation antibody modalities that are resilient to viral evolution. Here, we characterized amino-terminal domain (NTD)- and receptor binding domain (RBD)-specific monoclonal antibodies previously isolated from coronavirus disease 2019 (COVID-19) convalescent donors for their activity against emergent SARS-CoV-2 VOCs. Among these, the NTD-specific antibody C1596 displayed the greatest breadth of binding to VOCs, with cryo-electron microscopy structural analysis revealing recognition of a distinct NTD epitope outside of the site i antigenic supersite.

Comprehensive maps of escape mutations from antibodies 10-1074 and 3BNC117 for Envs from two divergent HIV strains.

Antibodies capable of neutralizing many strains of HIV are being explored as prophylactic and therapeutic agents, but viral escape mutations pose a major challenge. Efforts have been made to experimentally define the escape mutations from specific antibodies in specific viral strains, but it remains unclear how much the effects of mutations on neutralization differ among HIV strains. Here, we use pseudovirus deep mutational scanning to comprehensively map escape mutations from the V3 loop targeting antibody 10-1074 and the CD4-binding site targeting antibody 3BNC117 for both a clade A (BF520) and a clade B (TRO.

SARS-CoV-2 neutralizing antibody specificities differ dramatically between recently infected infants and immune-imprinted individuals.

The immune response to viral infection is shaped by past exposures to related virus strains, a phenomenon known as imprinting. For SARS-CoV-2, much of the population has been imprinted by a viral spike from an early strain, either through vaccination or infection during the early stages of the COVID-19 pandemic. As a consequence of this imprinting, infection with more recent SARS-CoV-2 strains primarily boosts cross-reactive antibodies elicited by the imprinting strain.

The mutation rate of SARS-CoV-2 is highly variable between sites and is influenced by sequence context, genomic region, and RNA structure.

RNA viruses like SARS-CoV-2 have a high mutation rate, which contributes to their rapid evolution. The rate of mutations depends on the mutation type (e.g.

Deep mutational scanning of rabies glycoprotein defines mutational constraint and antibody-escape mutations.

Rabies virus causes nearly 60,000 human deaths annually. Antibodies that target the rabies glycoprotein (G) are being developed as post-exposure prophylactics, but mutations in G can render such antibodies ineffective. Here, we use pseudovirus deep mutational scanning to measure how all single amino-acid mutations to G affect cell entry and neutralization by a panel of antibodies.

Defining a highly conserved B cell epitope in the receptor binding motif of SARS-CoV-2 spike glycoprotein.

SARS-CoV-2 mRNA vaccines induce robust and persistent germinal centre (GC) B cell responses in humans. It remains unclear how the continuous evolution of the virus impacts the breadth of the induced GC B cell response. Using ultrasound-guided fine needle aspiration, we examined draining lymph nodes of nine healthy adults following bivalent booster immunization.