Publications by authors named "Michael S Diamond"

475 Publications

Levels of circulating NS1 impact West Nile virus spread to the brain.

J Virol 2021 Aug 4:JVI0084421. Epub 2021 Aug 4.

Department of Pathology & Immunology, Washington University School of Medicine, St. Louis, MO, USA.

Dengue (DENV) and West Nile (WNV) viruses are arthropod-transmitted flaviviruses that respectively cause systemic vascular leakage and encephalitis syndromes in humans. However, the viral factors contributing to these specific clinical disorders are not completely understood. Flavivirus nonstructural protein 1 (NS1) is required for replication, expressed on the cell surface, and secreted as a soluble glycoprotein, reaching high levels in the blood of infected individuals. Extracellular DENV and WNV NS1 interact with host proteins and cells, have immune evasion functions, and promote endothelial dysfunction in a tissue-specific manner. To characterize how differences in DENV and WNV NS1 might function in pathogenesis, we generated WNV NS1 variants with substitutions corresponding to residues found in DENV NS1. We discovered that the substitution NS1-P101K led to reduced WNV infectivity of the brain and attenuated lethality in infected mice, although the virus replicated efficiently in cell culture and peripheral organs and bound at wild-type levels to brain endothelial cells and complement components. The P101K substitution resulted in reduced NS1 antigenemia in mice, and this was associated with reduced WNV spread to the brain. As exogenous administration of NS1 protein rescued WNV brain infectivity in mice, we conclude that circulating WNV NS1 facilitates viral dissemination into the central nervous system and impacts disease outcome. Flavivirus NS1 serves as an essential scaffolding molecule during virus replication but also is expressed on the cell surface and secreted as a soluble glycoprotein that circulates in the blood of infected individuals. Although extracellular forms of NS1 are implicated in immune modulation and in promoting endothelial dysfunction at blood-tissue barriers, it has been challenging to study specific effects of NS1 on pathogenesis without disrupting its key role in virus replication. Here we assessed West Nile virus (WNV) NS1 variants that do not affect virus replication and evaluated their effects on pathogenesis in mice. Our characterization of WNV NS1-P101K suggests that the levels of NS1 in circulation facilitate WNV dissemination to the brain and disease outcome. Our findings help understand the role of NS1 during flavivirus infection and support antiviral strategies for targeting circulating forms of NS1.
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http://dx.doi.org/10.1128/JVI.00844-21DOI Listing
August 2021

Tetravalent SARS-CoV-2 Neutralizing Antibodies Show Enhanced Potency and Resistance to Escape Mutations.

J Mol Biol 2021 Jul 27:167177. Epub 2021 Jul 27.

The Donnelly Centre, University of Toronto, Toronto, Canada. Electronic address:

Neutralizing antibodies (nAbs) hold promise as therapeutics against COVID-19. Here, we describe protein engineering and modular design principles that have led to the development of synthetic bivalent and tetravalent nAbs against SARS-CoV-2. The best nAb targets the host receptor binding site of the viral S-protein and tetravalent versions block entry with a potency exceeding bivalent nAbs by an order of magnitude. Structural studies show that both the bivalent and tetravalent nAbs can make multivalent interactions with a single S-protein trimer, consistent with the avidity and potency of these molecules. Significantly, we show that the tetravalent nAbs show increased tolerance to potential virus escape mutants and an emerging variant of concern. Bivalent and tetravalent nAbs can be produced at large-scale and are as stable and specific as approved antibody drugs. Our results provide a general framework for enhancing antiviral therapies against COVID-19 and related viral threats, and our strategy can be applied to virtually any antibody drug.
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http://dx.doi.org/10.1016/j.jmb.2021.167177DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8316672PMC
July 2021

Decreased antiviral immune response within the central nervous system of aged mice is associated with increased lethality of West Nile virus encephalitis.

Aging Cell 2021 Jul 30:e13412. Epub 2021 Jul 30.

Department of Internal Medicine, Division of Infectious Diseases, Washington University School of Medicine, Saint Louis, Missouri, USA.

West Nile virus (WNV) is an emerging pathogen that causes disease syndromes ranging from a mild flu-like illness to encephalitis. While the incidence of WNV infection is fairly uniform across age groups, the risk of lethal encephalitis increases with advanced age. Prior studies have demonstrated age-related, functional immune deficits that limit systemic antiviral immunity and increase mortality; however, the effect of age on antiviral immune responses specifically within the central nervous system (CNS) is unknown. Here, we show that aged mice exhibit increased peripheral organ and CNS tissue viral burden, the latter of which is associated with alterations in activation of both myeloid and lymphoid cells compared with similarly infected younger animals. Aged mice exhibit lower MHCII expression by microglia, and higher levels of PD1 and lower levels of IFNγ expression by WNV-specific CD8 T cells in the CNS and CD8 CD45 cells. These data indicate that the aged CNS exhibits limited local reactivation of T cells during viral encephalitis, which may lead to reduced virologic control at this site.
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http://dx.doi.org/10.1111/acel.13412DOI Listing
July 2021

An intranasal vaccine durably protects against SARS-CoV-2 variants in mice.

Cell Rep 2021 07 10;36(4):109452. Epub 2021 Jul 10.

Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pathology & Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA; The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO 63110, USA. Electronic address:

SARS-CoV-2 variants that attenuate antibody neutralization could jeopardize vaccine efficacy. We recently reported the protective activity of an intranasally administered spike protein-based chimpanzee adenovirus-vectored vaccine (ChAd-SARS-CoV-2-S) in animals, which has advanced to human trials. Here, we assessed its durability, dose response, and cross-protective activity in mice. A single intranasal dose of ChAd-SARS-CoV-2-S induced durably high neutralizing and Fc effector antibody responses in serum and S-specific IgG and IgA secreting long-lived plasma cells in the bone marrow. Protection against a historical SARS-CoV-2 strain was observed across a 100-fold vaccine dose range and over a 200-day period. At 6 weeks or 9 months after vaccination, serum antibodies neutralized SARS-CoV-2 strains with B.1.351, B.1.1.28, and B.1.617.1 spike proteins and conferred almost complete protection in the upper and lower respiratory tracts after challenge with variant viruses. Thus, in mice, intranasal immunization with ChAd-SARS-CoV-2-S provides durable protection against historical and emerging SARS-CoV-2 strains.
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http://dx.doi.org/10.1016/j.celrep.2021.109452DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8270739PMC
July 2021

Multivalent designed proteins protect against SARS-CoV-2 variants of concern.

bioRxiv 2021 Jul 7. Epub 2021 Jul 7.

Escape variants of SARS-CoV-2 are threatening to prolong the COVID-19 pandemic. To address this challenge, we developed multivalent protein-based minibinders as potential prophylactic and therapeutic agents. Homotrimers of single minibinders and fusions of three distinct minibinders were designed to geometrically match the SARS-CoV-2 spike (S) trimer architecture and were optimized by cell-free expression and found to exhibit virtually no measurable dissociation upon binding. Cryo-electron microscopy (cryoEM) showed that these trivalent minibinders engage all three receptor binding domains on a single S trimer. The top candidates neutralize SARS-CoV-2 variants of concern with IC values in the low pM range, resist viral escape, and provide protection in highly vulnerable human ACE2-expressing transgenic mice, both prophylactically and therapeutically. Our integrated workflow promises to accelerate the design of mutationally resilient therapeutics for pandemic preparedness.

One-sentence Summary: We designed, developed, and characterized potent, trivalent miniprotein binders that provide prophylactic and therapeutic protection against emerging SARS-CoV-2 variants of concern.
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http://dx.doi.org/10.1101/2021.07.07.451375DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8282097PMC
July 2021

Neutralisation of SARS-CoV-2 lineage P.1 by antibodies elicited through natural SARS-CoV-2 infection or vaccination with an inactivated SARS-CoV-2 vaccine: an immunological study.

Lancet Microbe 2021 Jul 8. Epub 2021 Jul 8.

Tropical Medicine Institute, Medical School, University of São Paulo, São Paulo, Brazil.

Background: Mutations accrued by SARS-CoV-2 lineage P.1-first detected in Brazil in early January, 2021-include amino acid changes in the receptor-binding domain of the viral spike protein that also are reported in other variants of concern, including B.1.1.7 and B.1.351. We aimed to investigate whether isolates of wild-type P.1 lineage SARS-CoV-2 can escape from neutralising antibodies generated by a polyclonal immune response.

Methods: We did an immunological study to assess the neutralising effects of antibodies on lineage P.1 and lineage B isolates of SARS-CoV-2, using plasma samples from patients previously infected with or vaccinated against SARS-CoV-2. Two specimens (P.1/28 and P.1/30) containing SARS-CoV-2 lineage P.1 (as confirmed by viral genome sequencing) were obtained from nasopharyngeal and bronchoalveolar lavage samples collected from patients in Manaus, Brazil, and compared against an isolate of SARS-CoV-2 lineage B (SARS.CoV2/SP02.2020) recovered from a patient in Brazil in February, 2020. Isolates were incubated with plasma samples from 21 blood donors who had previously had COVID-19 and from a total of 53 recipients of the chemically inactivated SARS-CoV-2 vaccine CoronaVac: 18 individuals after receipt of a single dose and an additional 20 individuals (38 in total) after receipt of two doses (collected 17-38 days after the most recent dose); and 15 individuals who received two doses during the phase 3 trial of the vaccine (collected 134-230 days after the second dose). Antibody neutralisation of P.1/28, P.1/30, and B isolates by plasma samples were compared in terms of median virus neutralisation titre (VNT, defined as the reciprocal value of the sample dilution that showed 50% protection against cytopathic effects).

Findings: In terms of VNT, plasma from individuals previously infected with SARS-CoV-2 had an 8·6 times lower neutralising capacity against the P.1 isolates (median VNT 30 [IQR <20-45] for P.1/28 and 30 [<20-40] for P.1/30) than against the lineage B isolate (260 [160-400]), with a binominal model showing significant reductions in lineage P.1 isolates compared with the lineage B isolate (p≤0·0001). Efficient neutralisation of P.1 isolates was not seen with plasma samples collected from individuals vaccinated with a first dose of CoronaVac 20-23 days earlier (VNTs below the limit of detection [<20] for most plasma samples), a second dose 17-38 days earlier (median VNT 24 [IQR <20-25] for P.1/28 and 28 [<20-25] for P.1/30), or a second dose 134-260 days earlier (all VNTs below limit of detection). Median VNTs against the lineage B isolate were 20 (IQR 20-30) after a first dose of CoronaVac 20-23 days earlier, 75 (<20-263) after a second dose 17-38 days earlier, and 20 (<20-30) after a second dose 134-260 days earlier. In plasma collected 17-38 days after a second dose of CoronaVac, neutralising capacity against both P.1 isolates was significantly decreased (p=0·0051 for P.1/28 and p=0·0336 for P.1/30) compared with that against the lineage B isolate. All data were corroborated by results obtained through plaque reduction neutralisation tests.

Interpretation: SARS-CoV-2 lineage P.1 might escape neutralisation by antibodies generated in response to polyclonal stimulation against previously circulating variants of SARS-CoV-2. Continuous genomic surveillance of SARS-CoV-2 combined with antibody neutralisation assays could help to guide national immunisation programmes.

Funding: São Paulo Research Foundation, Brazilian Ministry of Science, Technology and Innovation and Funding Authority for Studies, Medical Research Council, National Council for Scientific and Technological Development, National Institutes of Health.

Translation: For the Portuguese translation of the abstract see Supplementary Materials section.
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http://dx.doi.org/10.1016/S2666-5247(21)00129-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8266272PMC
July 2021

A single intranasal or intramuscular immunization with chimpanzee adenovirus-vectored SARS-CoV-2 vaccine protects against pneumonia in hamsters.

Cell Rep 2021 07 29;36(3):109400. Epub 2021 Jun 29.

Department of Internal Medicine, Washington University in Saint Louis School of Medicine, St. Louis, MO 63110, USA; Department of Molecular Microbiology and Microbial Pathogenesis, Washington University in Saint Louis School of Medicine, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University in Saint Louis School of Medicine, St. Louis, MO 63110, USA. Electronic address:

The development of an effective vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiologic agent of coronavirus disease 2019 (COVID-19), is a global priority. Here, we compare the protective capacity of intranasal and intramuscular delivery of a chimpanzee adenovirus-vectored vaccine encoding a prefusion stabilized spike protein (chimpanzee adenovirus [ChAd]-SARS-CoV-2-S) in Golden Syrian hamsters. Although immunization with ChAd-SARS-CoV-2-S induces robust spike-protein-specific antibodies capable of neutralizing the virus, antibody levels in serum are higher in hamsters vaccinated by an intranasal compared to intramuscular route. Accordingly, against challenge with SARS-CoV-2, ChAd-SARS-CoV-2-S-immunized hamsters are protected against less weight loss and have reduced viral infection in nasal swabs and lungs, and reduced pathology and inflammatory gene expression in the lungs, compared to ChAd-control immunized hamsters. Intranasal immunization with ChAd-SARS-CoV-2-S provides superior protection against SARS-CoV-2 infection and inflammation in the upper respiratory tract. These findings support intranasal administration of the ChAd-SARS-CoV-2-S candidate vaccine to prevent SARS-CoV-2 infection, disease, and possibly transmission.
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http://dx.doi.org/10.1016/j.celrep.2021.109400DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8238649PMC
July 2021

After the pandemic: perspectives on the future trajectory of COVID-19.

Nature 2021 Jul 8. Epub 2021 Jul 8.

Vir Biotechnology, San Francisco, CA, 94158, USA.

There is a realistic expectation that the global effort in vaccination will bring the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic under control. Nonetheless, uncertainties remain about the type of long-term association the virus will establish with the human population, particularly whether the coronavirus disease 2019 (COVID-19) will become an endemic disease. Although the trajectory is difficult to predict, the conditions, concepts, and variables that influence this transition can be anticipated. Persistence of SARS-CoV-2 as an endemic virus, perhaps with seasonal epidemic peaks, may be fueled by pockets of susceptible individuals and waning immunity after infection or vaccination, changes in the virus through antigenic drift that diminish protection, and reentries from zoonotic reservoirs. Here, we review relevant observations from previous epidemics and discuss the potential evolution of SARS-CoV-2 as it adapts during persistent transmission in the presence of a level of population immunity. Lack of effective surveillance or adequate response could enable the emergence of new epidemic or pandemic patterns from an endemic infection of SARS-CoV-2. There are key pieces of data that are urgently needed in order to make good decisions. We outline these and propose a way forward.
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http://dx.doi.org/10.1038/s41586-021-03792-wDOI Listing
July 2021

Assessment of serological assays for identifying high titer convalescent plasma.

Transfusion 2021 Jul 3. Epub 2021 Jul 3.

Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.

Background: The COVID-19 pandemic has been accompanied by the largest mobilization of therapeutic convalescent plasma (CCP) in over a century. Initial identification of high titer units was based on dose-response data using the Ortho VITROS IgG assay. The proliferation of severe acute respiratory syndrome coronavirus 2 serological assays and non-uniform application has led to uncertainty about their interrelationships. The purpose of this study was to establish correlations and analogous cutoffs between multiple serological assays.

Methods: We compared the Ortho, Abbott, Roche, an anti-spike (S) ELISA, and a virus neutralization assay. Relationships relative to FDA-approved cutoffs under the CCP emergency use authorization were identified in convalescent plasma from a cohort of 79 donors from April 2020.

Results: Relative to the neutralization assay, the spearman r value of the Ortho Clinical, Abbott, Roche, anti-S ELISA assays was 0.65, 0.59, 0.45, and 0.76, respectively. The best correlative index for establishing high-titer units was 3.87 signal-to-cutoff (S/C) for the Abbott, 13.82 cutoff index for the Roche, 1:1412 for the anti-S ELISA, 1:219 by the neutralization assay, and 15.9 S/C by the Ortho Clinical assay. The overall agreement using derived cutoffs compared to a neutralizing titer of 1:250 was 78.5% for Abbott, 74.7% for Roche, 83.5% for the anti-S ELISA, and 78.5% for Ortho Clinical.

Discussion: Assays based on antibodies against the nucleoprotein were positively associated with neutralizing titers and the Ortho assay, although their ability to distinguish FDA high-titer specimens was imperfect. The resulting relationships help reconcile results from the large body of serological data generated during the COVID-19 pandemic.
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http://dx.doi.org/10.1111/trf.16580DOI Listing
July 2021

Systematic analysis of SARS-CoV-2 infection of an ACE2-negative human airway cell.

Cell Rep 2021 07 23;36(2):109364. Epub 2021 Jun 23.

Department of Cell Biology and Physiology, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA; Department of Otolaryngology, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA. Electronic address:

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) variants govern transmissibility, responsiveness to vaccination, and disease severity. In a screen for new models of SARS-CoV-2 infection, we identify human H522 lung adenocarcinoma cells as naturally permissive to SARS-CoV-2 infection despite complete absence of angiotensin-converting enzyme 2 (ACE2) expression. Remarkably, H522 infection requires the E484D S variant; viruses expressing wild-type S are not infectious. Anti-S monoclonal antibodies differentially neutralize SARS-CoV-2 E484D S in H522 cells as compared to ACE2-expressing cells. Sera from vaccinated individuals block this alternative entry mechanism, whereas convalescent sera are less effective. Although the H522 receptor remains unknown, depletion of surface heparan sulfates block H522 infection. Temporally resolved transcriptomic and proteomic profiling reveal alterations in cell cycle and the antiviral host cell response, including MDA5-dependent activation of type I interferon signaling. These findings establish an alternative SARS-CoV-2 host cell receptor for the E484D SARS-CoV-2 variant, which may impact tropism of SARS-CoV-2 and consequently human disease pathogenesis.
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http://dx.doi.org/10.1016/j.celrep.2021.109364DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8220945PMC
July 2021

Ultrapotent miniproteins targeting the SARS-CoV-2 receptor-binding domain protect against infection and disease.

Cell Host Microbe 2021 07 24;29(7):1151-1161.e5. Epub 2021 Jun 24.

Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pathology & Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA; The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO 63110, USA. Electronic address:

Despite the introduction of public health measures and spike protein-based vaccines to mitigate the COVID-19 pandemic, SARS-CoV-2 infections and deaths continue to have a global impact. Previously, we used a structural design approach to develop picomolar range miniproteins targeting the SARS-CoV-2 spike receptor-binding domain. Here, we investigated the capacity of modified versions of one lead miniprotein, LCB1, to protect against SARS-CoV-2-mediated lung disease in mice. Systemic administration of LCB1-Fc reduced viral burden, diminished immune cell infiltration and inflammation, and completely prevented lung disease and pathology. A single intranasal dose of LCB1v1.3 reduced SARS-CoV-2 infection in the lung when given as many as 5 days before or 2 days after virus inoculation. Importantly, LCB1v1.3 protected in vivo against a historical strain (WA1/2020), an emerging B.1.1.7 strain, and a strain encoding key E484K and N501Y spike protein substitutions. These data support development of LCB1v1.3 for prevention or treatment of SARS-CoV-2 infection.
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http://dx.doi.org/10.1016/j.chom.2021.06.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8221914PMC
July 2021

Detection of antibodies neutralizing historical and emerging SARS-CoV-2 strains using a thermodynamically coupled de novo biosensor system.

bioRxiv 2021 Jun 22. Epub 2021 Jun 22.

With global vaccination efforts against SARS-CoV-2 underway, there is a need for rapid quantification methods for neutralizing antibodies elicited by vaccination and characterization of their strain dependence. Here, we describe a designed protein biosensor that enables sensitive and rapid detection of neutralizing antibodies against wild type and variant SARS-CoV-2 in serum samples. More generally, our thermodynamic coupling approach can better distinguish sample to sample differences in analyte binding affinity and abundance than traditional competition based assays.
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http://dx.doi.org/10.1101/2021.06.22.449355DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8240681PMC
June 2021

SARS-CoV-2 mRNA vaccines induce persistent human germinal centre responses.

Nature 2021 Jun 28. Epub 2021 Jun 28.

Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA.

SARS-CoV-2 mRNA-based vaccines are about 95% effective in preventing COVID-19. The dynamics of antibody-secreting plasmablasts and germinal centre B cells induced by these vaccines in humans remain unclear. Here we examined antigen-specific B cell responses in peripheral blood (n = 41) and draining lymph nodes in 14 individuals who had received 2 doses of BNT162b2, an mRNA-based vaccine that encodes the full-length SARS-CoV-2 spike (S) gene. Circulating IgG- and IgA-secreting plasmablasts that target the S protein peaked one week after the second immunization and then declined, becoming undetectable three weeks later. These plasmablast responses preceded maximal levels of serum anti-S binding and neutralizing antibodies to an early circulating SARS-CoV-2 strain as well as emerging variants, especially in individuals who had previously been infected with SARS-CoV-2 (who produced the most robust serological responses). By examining fine needle aspirates of draining axillary lymph nodes, we identified germinal centre B cells that bound S protein in all participants who were sampled after primary immunization. High frequencies of S-binding germinal centre B cells and plasmablasts were sustained in these draining lymph nodes for at least 12 weeks after the booster immunization. S-binding monoclonal antibodies derived from germinal centre B cells predominantly targeted the receptor-binding domain of the S protein, and fewer clones bound to the N-terminal domain or to epitopes shared with the S proteins of the human betacoronaviruses OC43 and HKU1. These latter cross-reactive B cell clones had higher levels of somatic hypermutation as compared to those that recognized only the SARS-CoV-2 S protein, which suggests a memory B cell origin. Our studies demonstrate that SARS-CoV-2 mRNA-based vaccination of humans induces a persistent germinal centre B cell response, which enables the generation of robust humoral immunity.
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http://dx.doi.org/10.1038/s41586-021-03738-2DOI Listing
June 2021

In vivo monoclonal antibody efficacy against SARS-CoV-2 variant strains.

Nature 2021 Jun 21. Epub 2021 Jun 21.

Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA.

Rapidly emerging SARS-CoV-2 variants jeopardize antibody-based countermeasures. Although cell culture experiments have demonstrated a loss of potency of several anti-spike neutralizing antibodies against variant strains of SARS-CoV-2, the in vivo importance of these results remains uncertain. Here we report the in vitro and in vivo activity of a panel of monoclonal antibodies (mAbs), which correspond to many in advanced clinical development by Vir Biotechnology, AbbVie, AstraZeneca, Regeneron and Lilly, against SARS-CoV-2 variant viruses. Although some individual mAbs showed reduced or abrogated neutralizing activity in cell culture against B.1.351, B.1.1.28, B.1.617.1 and B.1.526 viruses with mutations at residue E484 of the spike protein, low prophylactic doses of mAb combinations protected against infection by many variants in K18-hACE2 transgenic mice, 129S2 immunocompetent mice and hamsters, without the emergence of resistance. Exceptions were LY-CoV555 monotherapy and LY-CoV555 and LY-CoV016 combination therapy, both of which lost all protective activity, and the combination of AbbVie 2B04 and 47D11, which showed a partial loss of activity. When administered after infection, higher doses of several mAb cocktails protected in vivo against viruses with a B.1.351 spike gene. Therefore, many-but not all-of the antibody products with Emergency Use Authorization should retain substantial efficacy against the prevailing variant strains of SARS-CoV-2.
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http://dx.doi.org/10.1038/s41586-021-03720-yDOI Listing
June 2021

Cross-reactive coronavirus antibodies with diverse epitope specificities and Fc effector functions.

Cell Rep Med 2021 Jun 21;2(6):100313. Epub 2021 May 21.

Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA.

The continual emergence of novel coronaviruses (CoV), such as severe acute respiratory syndrome-(SARS)-CoV-2, highlights the critical need for broadly reactive therapeutics and vaccines against this family of viruses. From a recovered SARS-CoV donor sample, we identify and characterize a panel of six monoclonal antibodies that cross-react with CoV spike (S) proteins from the highly pathogenic SARS-CoV and SARS-CoV-2, and demonstrate a spectrum of reactivity against other CoVs. Epitope mapping reveals that these antibodies recognize multiple epitopes on SARS-CoV-2 S, including the receptor-binding domain, the N-terminal domain, and the S2 subunit. Functional characterization demonstrates that the antibodies mediate phagocytosis-and in some cases trogocytosis-but not neutralization . When tested in murine models, two of the antibodies demonstrate a reduction in hemorrhagic pathology in the lungs. The identification of cross-reactive epitopes recognized by functional antibodies expands the repertoire of targets for pan-coronavirus vaccine design strategies.
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http://dx.doi.org/10.1016/j.xcrm.2021.100313DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8139315PMC
June 2021

Hypergraph models of biological networks to identify genes critical to pathogenic viral response.

BMC Bioinformatics 2021 May 29;22(1):287. Epub 2021 May 29.

Computing and Analytics Division, Pacific Northwest National Laboratory, Seattle, WA, USA.

Background: Representing biological networks as graphs is a powerful approach to reveal underlying patterns, signatures, and critical components from high-throughput biomolecular data. However, graphs do not natively capture the multi-way relationships present among genes and proteins in biological systems. Hypergraphs are generalizations of graphs that naturally model multi-way relationships and have shown promise in modeling systems such as protein complexes and metabolic reactions. In this paper we seek to understand how hypergraphs can more faithfully identify, and potentially predict, important genes based on complex relationships inferred from genomic expression data sets.

Results: We compiled a novel data set of transcriptional host response to pathogenic viral infections and formulated relationships between genes as a hypergraph where hyperedges represent significantly perturbed genes, and vertices represent individual biological samples with specific experimental conditions. We find that hypergraph betweenness centrality is a superior method for identification of genes important to viral response when compared with graph centrality.

Conclusions: Our results demonstrate the utility of using hypergraphs to represent complex biological systems and highlight central important responses in common to a variety of highly pathogenic viruses.
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http://dx.doi.org/10.1186/s12859-021-04197-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8164482PMC
May 2021

SARS-CoV-2 exacerbates proinflammatory responses in myeloid cells through C-type lectin receptors and Tweety family member 2.

Immunity 2021 06 9;54(6):1304-1319.e9. Epub 2021 May 9.

Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06519, USA.

Despite mounting evidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) engagement with immune cells, most express little, if any, of the canonical receptor of SARS-CoV-2, angiotensin-converting enzyme 2 (ACE2). Here, using a myeloid cell receptor-focused ectopic expression screen, we identified several C-type lectins (DC-SIGN, L-SIGN, LSECtin, ASGR1, and CLEC10A) and Tweety family member 2 (TTYH2) as glycan-dependent binding partners of the SARS-CoV-2 spike. Except for TTYH2, these molecules primarily interacted with spike via regions outside of the receptor-binding domain. Single-cell RNA sequencing analysis of pulmonary cells from individuals with coronavirus disease 2019 (COVID-19) indicated predominant expression of these molecules on myeloid cells. Although these receptors do not support active replication of SARS-CoV-2, their engagement with the virus induced robust proinflammatory responses in myeloid cells that correlated with COVID-19 severity. We also generated a bispecific anti-spike nanobody that not only blocked ACE2-mediated infection but also the myeloid receptor-mediated proinflammatory responses. Our findings suggest that SARS-CoV-2-myeloid receptor interactions promote immune hyperactivation, which represents potential targets for COVID-19 therapy.
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http://dx.doi.org/10.1016/j.immuni.2021.05.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8106883PMC
June 2021

Profiling B cell immunodominance after SARS-CoV-2 infection reveals antibody evolution to non-neutralizing viral targets.

Immunity 2021 06 6;54(6):1290-1303.e7. Epub 2021 May 6.

Department of Medicine, Washington University School of Medicine, St Louis, MO 63130, USA.

Dissecting the evolution of memory B cells (MBCs) against SARS-CoV-2 is critical for understanding antibody recall upon secondary exposure. Here, we used single-cell sequencing to profile SARS-CoV-2-reactive B cells in 38 COVID-19 patients. Using oligo-tagged antigen baits, we isolated B cells specific to the SARS-CoV-2 spike, nucleoprotein (NP), open reading frame 8 (ORF8), and endemic human coronavirus (HCoV) spike proteins. SARS-CoV-2 spike-specific cells were enriched in the memory compartment of acutely infected and convalescent patients several months post symptom onset. With severe acute infection, substantial populations of endemic HCoV-reactive antibody-secreting cells were identified and possessed highly mutated variable genes, signifying preexisting immunity. Finally, MBCs exhibited pronounced maturation to NP and ORF8 over time, especially in older patients. Monoclonal antibodies against these targets were non-neutralizing and non-protective in vivo. These findings reveal antibody adaptation to non-neutralizing intracellular antigens during infection, emphasizing the importance of vaccination for inducing neutralizing spike-specific MBCs.
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http://dx.doi.org/10.1016/j.immuni.2021.05.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8101792PMC
June 2021

SARS-CoV-2 ferritin nanoparticle vaccines elicit broad SARS coronavirus immunogenicity.

bioRxiv 2021 May 10. Epub 2021 May 10.

The need for SARS-CoV-2 next-generation vaccines has been highlighted by the rise of variants of concern (VoC) and the long-term threat of other coronaviruses. Here, we designed and characterized four categories of engineered nanoparticle immunogens that recapitulate the structural and antigenic properties of prefusion Spike (S), S1 and RBD. These immunogens induced robust S-binding, ACE2-inhibition, and authentic and pseudovirus neutralizing antibodies against SARS-CoV-2 in mice. A Spike-ferritin nanoparticle (SpFN) vaccine elicited neutralizing titers more than 20-fold higher than convalescent donor serum, following a single immunization, while RBD-Ferritin nanoparticle (RFN) immunogens elicited similar responses after two immunizations. Passive transfer of IgG purified from SpFN- or RFN-immunized mice protected K18-hACE2 transgenic mice from a lethal SARS-CoV-2 virus challenge. Furthermore, SpFN- and RFN-immunization elicited ACE2 blocking activity and neutralizing ID50 antibody titers >2,000 against SARS-CoV-1, along with high magnitude neutralizing titers against major VoC. These results provide design strategies for pan-coronavirus vaccine development.

Highlights: Iterative structure-based design of four Spike-domain Ferritin nanoparticle classes of immunogensSpFN-ALFQ and RFN-ALFQ immunization elicits potent neutralizing activity against SARS-CoV-2, variants of concern, and SARS-CoV-1Passively transferred IgG from immunized C57BL/6 mice protects K18-hACE2 mice from lethal SARS-CoV-2 challenge.
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http://dx.doi.org/10.1101/2021.05.09.443331DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8132231PMC
May 2021

Common Mechanism of SARS-CoV and SARS-CoV-2 Pathogenesis across Species.

bioRxiv 2021 May 14. Epub 2021 May 14.

Sarbecovirus (CoV) infections, including Severe Acute Respiratory CoV (SARS-CoV) and SARS-CoV-2, are considerable human threats. Human GWAS studies have recently identified loci associated with variation in SARS-CoV-2 susceptibility. However, genetically tractable models that reproduce human CoV disease outcomes are needed to mechanistically evaluate genetic determinants of CoV susceptibility. We used the Collaborative Cross (CC) and human GWAS datasets to elucidate host susceptibility loci that regulate CoV infections and to identify host quantitative trait loci that modulate severe CoV and pan-CoV disease outcomes including a major disease regulating loci including ablation resulted in enhanced titer, weight loss, respiratory dysfunction, mortality, and inflammation, providing mechanistic support in mitigating protection from severe SARS-CoV-2 pathogenesis across species. This study represents a comprehensive analysis of susceptibility loci for an entire genus of human pathogens conducted, identifies a large collection of susceptibility loci and candidate genes that regulate multiple aspects type-specific and cross-CoV pathogenesis, and also validates the paradigm of using the CC platform to identify common cross-species susceptibility loci and genes for newly emerging and pre-epidemic viruses.
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http://dx.doi.org/10.1101/2021.05.14.444205DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8132217PMC
May 2021

Western diet induces Paneth cell defects through microbiome alterations and farnesoid X receptor and type I interferon activation.

Cell Host Microbe 2021 06 18;29(6):988-1001.e6. Epub 2021 May 18.

Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO 63110, USA. Electronic address:

Intestinal Paneth cells modulate innate immunity and infection. In Crohn's disease, genetic mutations together with environmental triggers can disable Paneth cell function. Here, we find that a western diet (WD) similarly leads to Paneth cell dysfunction through mechanisms dependent on the microbiome and farnesoid X receptor (FXR) and type I interferon (IFN) signaling. Analysis of multiple human cohorts suggests that obesity is associated with Paneth cell dysfunction. In mouse models, consumption of a WD for as little as 4 weeks led to Paneth cell dysfunction. WD consumption in conjunction with Clostridium spp. increased the secondary bile acid deoxycholic acid levels in the ileum, which in turn inhibited Paneth cell function. The process required excess signaling of both FXR and IFN within intestinal epithelial cells. Our findings provide a mechanistic link between poor diet and inhibition of gut innate immunity and uncover an effect of FXR activation in gut inflammation.
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http://dx.doi.org/10.1016/j.chom.2021.04.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8192497PMC
June 2021

Differential usage of transcriptional repressor Zeb2 enhancers distinguishes adult and embryonic hematopoiesis.

Immunity 2021 Jul 17;54(7):1417-1432.e7. Epub 2021 May 17.

Department of Pathology and Immunology, Washington University in St. Louis, School of Medicine, St. Louis, MO 63110, USA. Electronic address:

The transcriptional repressor ZEB2 regulates development of many cell fates among somatic, neural, and hematopoietic lineages, but the basis for its requirement in these diverse lineages is unclear. Here, we identified a 400-basepair (bp) region located 165 kilobases (kb) upstream of the Zeb2 transcriptional start site (TSS) that binds the E proteins at several E-box motifs and was active in hematopoietic lineages. Germline deletion of this 400-bp region (Zeb2mice) specifically prevented Zeb2 expression in hematopoietic stem cell (HSC)-derived lineages. Zeb2 mice lacked development of plasmacytoid dendritic cells (pDCs), monocytes, and B cells. All macrophages in Zeb2 mice were exclusively of embryonic origin. Using single-cell chromatin profiling, we identified a second Zeb2 enhancer located at +164-kb that was selectively active in embryonically derived lineages, but not HSC-derived ones. Thus, Zeb2 expression in adult, but not embryonic, hematopoiesis is selectively controlled by the -165-kb Zeb2 enhancer.
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http://dx.doi.org/10.1016/j.immuni.2021.04.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8282756PMC
July 2021

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

bioRxiv 2021 May 3. Epub 2021 May 3.

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 SARS-CoV-2 infection or in plasmablasts from an individual after vaccination with mRNA-encoded spike protein. We identified 29 public clonotypes, including clones recognizing the receptor-binding domain (RBD) in the spike protein S1 subunit (including a neutralizing, ACE2-blocking clone that protects ), and others recognizing non-RBD epitopes that bound the heptad repeat 1 region of the S2 domain. Germline-revertant forms of some public clonotypes bound efficiently to spike protein, suggesting these common germline-encoded antibodies are preconfigured for avid recognition. Identification of large numbers of public clonotypes provides insight into the molecular basis of efficacy of SARS-CoV-2 vaccines and sheds light on the immune pressures driving the selection of common viral escape mutants.
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http://dx.doi.org/10.1101/2021.05.02.442326DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8109196PMC
May 2021

Efficacy and breadth of adjuvanted SARS-CoV-2 receptor-binding domain nanoparticle vaccine in macaques.

bioRxiv 2021 Apr 10. Epub 2021 Apr 10.

Emergence of novel variants of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) underscores the need for next-generation vaccines able to elicit broad and durable immunity. Here we report the evaluation of a ferritin nanoparticle vaccine displaying the receptor-binding domain of the SARS-CoV-2 spike protein (RFN) adjuvanted with Army Liposomal Formulation QS-21 (ALFQ). RFN vaccination of macaques using a two-dose regimen resulted in robust, predominantly Th1 CD4+ T cell responses and reciprocal peak mean neutralizing antibody titers of 14,000-21,000. Rapid control of viral replication was achieved in the upper and lower airways of animals after high-dose SARS-CoV-2 respiratory challenge, with undetectable replication within four days in 7 of 8 animals receiving 50 µg RFN. Cross-neutralization activity against SARS-CoV-2 variant B.1.351 decreased only ∼2-fold relative to USA-WA1. In addition, neutralizing, effector antibody and cellular responses targeted the heterotypic SARS-CoV-1, highlighting the broad immunogenicity of RFN-ALFQ for SARS-like betacoronavirus vaccine development.

Significance Statement: The emergence of SARS-CoV-2 variants of concern (VOC) that reduce the efficacy of current COVID-19 vaccines is a major threat to pandemic control. We evaluate a SARS-CoV-2 Spike receptor-binding domain ferritin nanoparticle protein vaccine (RFN) in a nonhuman primate challenge model that addresses the need for a next-generation, efficacious vaccine with increased pan-SARS breadth of coverage. RFN, adjuvanted with a liposomal-QS21 formulation (ALFQ), elicits humoral and cellular immune responses exceeding those of current vaccines in terms of breadth and potency and protects against high-dose respiratory tract challenge. Neutralization activity against the B.1.351 VOC within two-fold of wild-type virus and against SARS-CoV-1 indicate exceptional breadth. Our results support consideration of RFN for SARS-like betacoronavirus vaccine development.
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http://dx.doi.org/10.1101/2021.04.09.439166DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8043445PMC
April 2021

Broadly neutralizing monoclonal antibodies protect against multiple tick-borne flaviviruses.

J Exp Med 2021 May;218(5)

Department of Medicine, Washington University School of Medicine, St. Louis, MO.

Although Powassan virus (POWV) is an emerging tick-transmitted flavivirus that causes severe or fatal neuroinvasive disease in humans, medical countermeasures have not yet been developed. Here, we developed a panel of neutralizing anti-POWV mAbs recognizing six distinct antigenic sites. The most potent of these mAbs bind sites within domain II or III of the envelope (E) protein and inhibit postattachment viral entry steps. A subset of these mAbs cross-react with other flaviviruses. Both POWV type-specific and cross-reactive neutralizing mAbs confer protection in mice against POWV infection when given as prophylaxis or postexposure therapy. Several cross-reactive mAbs mapping to either domain II or III also protect in vivo against heterologous tick-transmitted flaviviruses including Langat and tick-borne encephalitis virus. Our experiments define structural and functional correlates of antibody protection against POWV infection and identify epitopes targeted by broadly neutralizing antibodies with therapeutic potential against multiple tick-borne flaviviruses.
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http://dx.doi.org/10.1084/jem.20210174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8040518PMC
May 2021

The mechanistic basis of protection by non-neutralizing anti-alphavirus antibodies.

Cell Rep 2021 Apr;35(1):108962

Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA; The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine. St. Louis, MO 63110, USA. Electronic address:

Although neutralizing monoclonal antibodies (mAbs) against epitopes within the alphavirus E2 protein can protect against infection, the functional significance of non-neutralizing mAbs is poorly understood. Here, we evaluate the activity of 13 non-neutralizing mAbs against Mayaro virus (MAYV), an emerging arthritogenic alphavirus. These mAbs bind to the MAYV virion and surface of infected cells but fail to neutralize infection in cell culture. Mapping studies identify six mAb binding groups that localize to discrete epitopes within or adjacent to the A domain of the E2 glycoprotein. Remarkably, passive transfer of non-neutralizing mAbs protects against MAYV infection and disease in mice, and their efficacy requires Fc effector functions. Monocytes mediate the protection of non-neutralizing mAbs in vivo, as Fcγ-receptor-expressing myeloid cells facilitate the binding, uptake, and clearance of MAYV without antibody-dependent enhancement of infection. Humoral protection against alphaviruses likely reflects contributions from non-neutralizing antibodies through Fc-dependent mechanisms that accelerate viral clearance.
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http://dx.doi.org/10.1016/j.celrep.2021.108962DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8055377PMC
April 2021

Assessment of serological assays for identifying high titer convalescent plasma.

medRxiv 2021 Mar 28. Epub 2021 Mar 28.

Department of Pathology & Immunology. Washington University School of Medicine. St. Louis, MO.

The COVID-19 pandemic has been accompanied by the largest mobilization of therapeutic convalescent plasma (CCP) in over a century. Initial identification of high titer units was based on dose-response data using the Ortho VITROS IgG assay. The proliferation of SARS-CoV-2 serological assays and non-uniform application has led to uncertainty about their interrelationships. The purpose of this study was to establish correlations and analogous cutoffs between commercially available serological tests (Ortho, Abbott, Roche), a spike ELISA, and a virus neutralization assay using convalescent plasma from a cohort of 79 donors from April 2020. Relationships relative to FDA-approved cutoffs under the CCP EUA were identified by linear regression and receiver operator characteristic curves. Relative to the Ortho VITROS assay, the r of the Abbott, Roche, the anti-Spike ELISA and the neutralizing assay were 0.58, 0.5, 0.82, and 0.44, respectively. The best correlative index for establishing high-titer units was 3.82 S/C for the Abbott, 10.89 COI for the Roche, 1:1,202 for the anti-Spike ELISA, and 1:200 by the neutralization assay. The overall agreement using derived cutoffs compared to the CCP EUA Ortho VITROS cutoff of 9.5 was 92.4% for Abbott, 84.8% for Roche, 87.3% for the anti-S ELISA and 78.5% for the neutralization assay. Assays based on antibodies against the nucleoprotein (Roche, Abbott) and neutralizing antibody tests were positively associated with the Ortho assay, although their ability to distinguish FDA high-titer specimens was imperfect. The resulting relationships help reconcile results from the large body of serological data generated during the COVID-19 pandemic.
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http://dx.doi.org/10.1101/2021.03.26.21254427DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8010743PMC
March 2021

A public vaccine-induced human antibody protects against SARS-CoV-2 and emerging variants.

bioRxiv 2021 Mar 24. Epub 2021 Mar 24.

The emergence of antigenically distinct severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with increased transmissibility is a public health threat. Some of these variants show substantial resistance to neutralization by SARS-CoV-2 infection- or vaccination-induced antibodies, which principally target the receptor binding domain (RBD) on the virus spike glycoprotein. Here, we describe 2C08, a SARS-CoV-2 mRNA vaccine-induced germinal center B cell-derived human monoclonal antibody that binds to the receptor binding motif within the RBD. 2C08 broadly neutralizes SARS-CoV-2 variants with remarkable potency and reduces lung inflammation, viral load, and morbidity in hamsters challenged with either an ancestral SARS-CoV-2 strain or a recent variant of concern. Clonal analysis identified 2C08-like public clonotypes among B cell clones responding to SARS-CoV-2 infection or vaccination in at least 20 out of 78 individuals. Thus, 2C08-like antibodies can be readily induced by SARS-CoV-2 vaccines and mitigate resistance by circulating variants of concern.

One Sentence Summary: Protection against SARS-CoV-2 variants by a potently neutralizing vaccine-induced human monoclonal antibody.
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http://dx.doi.org/10.1101/2021.03.24.436864DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8010723PMC
March 2021

Efficacy of a Broadly Neutralizing SARS-CoV-2 Ferritin Nanoparticle Vaccine in Nonhuman Primates.

bioRxiv 2021 Mar 25. Epub 2021 Mar 25.

The emergence of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants stresses the continued need for next-generation vaccines that confer broad protection against coronavirus disease 2019 (COVID-19). We developed and evaluated an adjuvanted SARS-CoV-2 Spike Ferritin Nanoparticle (SpFN) vaccine in nonhuman primates (NHPs). High-dose (50 g) SpFN vaccine, given twice within a 28 day interval, induced a Th1-biased CD4 T cell helper response and a peak neutralizing antibody geometric mean titer of 52,773 against wild-type virus, with activity against SARS-CoV-1 and minimal decrement against variants of concern. Vaccinated animals mounted an anamnestic response upon high-dose SARS-CoV-2 respiratory challenge that translated into rapid elimination of replicating virus in their upper and lower airways and lung parenchyma. SpFN's potent and broad immunogenicity profile and resulting efficacy in NHPs supports its utility as a candidate platform for SARS-like betacoronaviruses.

One-sentence Summary: A SARS-CoV-2 Spike protein ferritin nanoparticle vaccine, co-formulated with a liposomal adjuvant, elicits broad neutralizing antibody responses that exceed those observed for other major vaccines and rapidly protects against respiratory infection and disease in the upper and lower airways and lung tissue of nonhuman primates.
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http://dx.doi.org/10.1101/2021.03.24.436523DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8010721PMC
March 2021

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

Cell 2021 04 16;184(9):2316-2331.e15. Epub 2021 Mar 16.

Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA. Electronic address:

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.
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http://dx.doi.org/10.1016/j.cell.2021.03.029DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7962591PMC
April 2021
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