Imprinted antibody responses against SARS-CoV-2 Omicron sublineages

SARS-CoV-2 Omicron sublineages carry distinct spike mutations and represent an antigenic shift resulting in escape from antibodies induced by previous infection or vaccination. We show that hybrid immunity or vaccine boosters result in potent plasma neutralizing activity against Omicron BA.1 and BA.2 and that breakthrough infections, but not vaccination-only, induce neutralizing activity in the nasal mucosa. Consistent with immunological imprinting, most antibodies derived from memory B cells or plasma cells of Omicron breakthrough cases cross-react with the Wuhan-Hu-1, BA.1 and BA.2 receptor-binding domains whereas Omicron primary infections elicit B cells of narrow specificity. While most clinical antibodies have reduced neutralization of Omicron, we identified an ultrapotent pan-variant antibody, that is unaffected by any Omicron lineage spike mutations and is a strong candidate for clinical development.

Structural changes in the SARS-CoV-2 spike E406W mutant escaping a clinical monoclonal antibody cocktail

The SARS-CoV-2 receptor-binding domain (RBD) E406W mutation abrogates neutralization mediated by the REGEN-CoV therapeutic monoclonal antibody (mAb) COVID-19 cocktail and the cilgavimab (AZD1061) mAb. Here, we show that this residue substitution remodels the ACE2-binding site allosterically, thereby dampening receptor recognition severely and altering the epitopes recognized by these three mAbs. Although vaccine-elicited neutralizing antibody titers are decreased similarly against the E406 mutant and the Delta or Epsilon variants, broadly neutralizing sarbecovirus mAbs, including a clinical mAb, inhibit the E406W spike mutant.

Reference diameter and characteristics of the distal radial artery based on ultrasonographic assessment

Background/Aims@#While distal radial artery (DRA) access is increasingly being used for diagnostic coronary angiography, limited information is available regarding DRA size. We aimed to determine the DRA reference diameters of Korean patients and identify the predictors of DRA diameter < 2.3 mm. @*Methods@#The outer bilateral DRA diameters were assessed using a linear ultrasound probe in 1,162 consecutive patients who underwent transthoracic echocardiography. The DRA diameter was measured by the perpendicular angle in the dorsum of the hand, and the average values were compared by sex. DRA diameter < 2.3 mm was defined as unsuitable for routine diagnostic coronary angiography using a 5 Fr introducer sheath. @*Results@#The mean DRA diameters were 2.31 ± 0.43 mm (right) and 2.35 ± 0.45 mm (left). The DRA was smaller in women than men (right: 2.15 ± 0.38 mm vs. 2.43 ± 0.44 mm, p < 0.001; left: 2.18 ± 0.39 mm vs. 2.47 ± 0.45 mm, p < 0.001). The DRA diameter was approximately 20% smaller than the radial artery diameter. A total of 630 (54.2%) and 574 (49.4%) patients had DRA diameter < 2.3 mm in the right and left hands, respectively. Female sex, low body mass index (BMI), and low body surface area (BSA) were significant predictors of DRA diameter < 2.3 mm. @*Conclusions@#We provided reference DRA diameters for Korean patients. Approximately 50% of the studied patients had DRA diameter < 2.3 mm. Female sex, low BMI, and low BSA remained significant predictors of DRA diameter < 2.3 mm.

Artificial Intelligence for Detection of CardiovascularRelated Diseases from Wearable Devices:A Systematic Review and Meta-Analysis

Purpose@#Several artificial intelligence (AI) models for the detection and prediction of cardiovascular-related diseases, including arrhythmias, diabetes, and sleep apnea, have been reported. This systematic review and meta-analysis aimed to identify AI models developed for or applicable to wearable and mobile devices for diverse cardiovascular-related diseases. @*Materials and Methods@#The searched databases included Medline, Embase, and Cochrane Library. For AI models for atrial fibrillation (AF) detection, a meta-analysis of diagnostic accuracy was performed to summarize sensitivity and specificity. @*Results@#A total of 102 studies were included in the qualitative review. There were AI models for the detection of arrythmia (n=62), followed by sleep apnea (n=11), peripheral vascular diseases (n=6), diabetes mellitus (n=5), hyper/hypotension (n=5), valvular heart disease (n=4), heart failure (n=3), myocardial infarction and cardiac arrest (n=2), and others (n=4). For quantitative analysis of 26 studies reporting AI models for AF detection, meta-analyzed sensitivity was 94.80% and specificity was 96.96%. Deep neural networks showed superior performance [meta-analyzed area under receiver operating characteristics curve (AUROC) of 0.981] compared to conventional machine learning algorithms (meta-analyzed AUROC of 0.961). However, AI models tested with proprietary dataset (meta-analyzed AUROC of 0.972) or data acquired from wearable devices (meta-analyzed AUROC of 0.977) showed inferior performance than those with public dataset (meta-analyzed AUROC of 0.986) or data from in-hospital devices (meta-analyzed AUROC of 0.983). @*Conclusion@#This review found that AI models for diverse cardiovascular-related diseases are being developed, and that they are gradually developing into a form that is suitable for wearable and mobile devices.

Structure, receptor recognition and antigenicity of the human coronavirus CCoV-HuPn-2018 spike glycoprotein

The recent isolation of CCoV-HuPn-2018 from a child respiratory swab indicates that more coronaviruses are spilling over to humans than previously appreciated. Here, we determined cryo-electron microscopy structures of the CCoV-HuPn-2018 spike glycoprotein trimer in two distinct conformational states and identified that it binds canine, feline and porcine aminopeptidase N (APN encoded by ANPEP) orthologs which serve as entry receptors. Introduction of an oligosaccharide at position N739 of human APN renders cells susceptible to CCoV-HuPn-2018 spike-mediated entry, suggesting that single nucleotide polymorphisms could account for the detection of this virus in some individuals. Human polyclonal plasma antibodies elicited by HCoV-229E infection and a porcine coronavirus monoclonal antibody inhibit CCoV-HuPn-2018 S-mediated entry, indicating elicitation of cross-neutralizing activity among -coronaviruses. These data provide a blueprint of the CCoV-HuPn-2018 infection machinery, unveil the viral entry receptor and pave the way for vaccine and therapeutic development targeting this zoonotic pathogen.

Antibody-mediated broad sarbecovirus neutralization through ACE2 molecular mimicry

Understanding broadly neutralizing sarbecovirus antibody responses is key to developing countermeasures effective against SARS-CoV-2 variants and future spillovers of other sarbecoviruses. Here we describe the isolation and characterization of a human monoclonal antibody, designated S2K146, broadly neutralizing viruses belonging to all three sarbecovirus clades known to utilize ACE2 as entry receptor and protecting therapeutically against SARS-CoV-2 beta challenge in hamsters. Structural and functional studies show that most of the S2K146 epitope residues are shared with the ACE2 binding site and that the antibody inhibits receptor attachment competitively. Viral passaging experiments underscore an unusually high barrier for emergence of escape mutants making it an ideal candidate for clinical development. These findings unveil a key site of vulnerability for the development of a next generation of vaccines eliciting broad sarbecovirus immunity.

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

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 IC50 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 SummaryWe designed, developed, and characterized potent, trivalent miniprotein binders that provide prophylactic and therapeutic protection against emerging SARS-CoV-2 variants of concern.

Antibodies to the SARS-CoV-2 receptor-binding domain that maximize breadth and resistance to viral escape

An ideal anti-SARS-CoV-2 antibody would resist viral escape1-3, have activity against diverse SARS-related coronaviruses4-7, and be highly protective through viral neutralization8-11 and effector functions12,13. Understanding how these properties relate to each other and vary across epitopes would aid development of antibody therapeutics and guide vaccine design. Here, we comprehensively characterize escape, breadth, and potency across a panel of SARS-CoV-2 antibodies targeting the receptor-binding domain (RBD), including S3094, the parental antibody of the late-stage clinical antibody VIR-7831. We observe a tradeoff between SARS-CoV-2 in vitro neutralization potency and breadth of binding across SARS-related coronaviruses. Nevertheless, we identify several neutralizing antibodies with exceptional breadth and resistance to escape, including a new antibody (S2H97) that binds with high affinity to all SARS-related coronavirus clades via a unique RBD epitope centered on residue E516. S2H97 and other escape-resistant antibodies have high binding affinity and target functionally constrained RBD residues. We find that antibodies targeting the ACE2 receptor binding motif (RBM) typically have poor breadth and are readily escaped by mutations despite high neutralization potency, but we identify one potent RBM antibody (S2E12) with breadth across sarbecoviruses closely related to SARS-CoV-2 and with a high barrier to viral escape. These data highlight functional diversity among antibodies targeting the RBD and identify epitopes and features to prioritize for antibody and vaccine development against the current and potential future pandemics.

Membrane lectins enhance SARS-CoV-2 infection and influence the neutralizing activity of different classes of antibodies

Investigating the mechanisms of SARS-CoV-2 cellular infection is key to better understand COVID-19 immunity and pathogenesis. Infection, which involves both cell attachment and membrane fusion, relies on the ACE2 receptor that is paradoxically found at low levels in the respiratory tract, suggesting that additional mechanisms facilitating infection may exist. Here we show that C-type lectin receptors, DC-SIGN, L-SIGN and the sialic acid-binding Ig-like lectin 1 (SIGLEC1) function as auxiliary receptors by enhancing ACE2-mediated infection and modulating the neutralizing activity of different classes of spike-specific antibodies. Antibodies to the N-terminal domain (NTD) or to the conserved proteoglycan site at the base of the Receptor Binding Domain (RBD), while poorly neutralizing infection of ACE2 over-expressing cells, effectively block lectin-facilitated infection. Conversely, antibodies to the Receptor Binding Motif (RBM), while potently neutralizing infection of ACE2 over-expressing cells, poorly neutralize infection of cells expressing DC-SIGN or L-SIGN and trigger fusogenic rearrangement of the spike promoting cell-to-cell fusion. Collectively, these findings identify a lectin-dependent pathway that enhances ACE2-dependent infection by SARS-CoV-2 and reveal distinct mechanisms of neutralization by different classes of spike-specific antibodies.

Retroperitoneal Viscum album extract instillation in patients with a large amount of drainage after kidney transplantation

Purpose@#After kidney transplantation (KT), a large amount of drainage can delay postoperative recovery. Viscum album extract is an agent used in pleurodesis, and the purpose of this study was to evaluate the efficacy of this agent in reducing the amount of drainage after KT. @*Methods@#Medical records of patients with a large amount of drainage (≥ 100 mL/day) on postoperative day (POD) 7 after KT who had undergone V. album extract instillation through drainage tube (n = 115) or conservative management (n = 177) were retrospectively reviewed. The primary endpoint was a decrease in the amount of drainage on POD 14 from POD 7. @*Results@#A decrease in the amount of drainage on POD 14 from POD 7 was larger in the V. album extract instillation group than in the conservative management group (–228.3 ± 181.6 mL vs. –144.6 ± 202.0 mL, P < 0.001). Duration of hospitalization after operation was shorter in the V. album extract instillation group than in the conservative management group (15.9 ± 3.2 days vs. 18.1 ± 5.3 days, P < 0.001). In multivariate analysis, there was a statistically significant association of V. album extract instillation with lower risk of persistent large amount of drainage (≥ 100 mL/day on POD 14), with an odds ratio of 0.57 (95% confidence interval, 0.35–0.93; P = 0.026). @*Conclusion@#Retroperitoneal V. album extract instillation could be effective in reducing the amount of drainage and promoting postoperative recovery in patients with a large amount of drainage after KT.

Short- and Long-Term Exposure to Particulate Matter and Pulse Wave Velocity / 가정의학회지

Background@#In hemodialysis patients, brachial-ankle pulse wave velocity (baPWV) levels are affected by particulate matter with an aerodynamic diameter of 10 μm or less (PM10). We conducted this study to determine whether there is an association between short- and long-term PM10 exposure and baPWV in apparently healthy adults aged 40 years and older. @*Methods@#A total of 1,628 subjects who underwent health examinations between 2006 and 2009 were included in the study. On the basis of the day of medical screening, the 1–3-day and 365-day moving averages of PM10 concentrations were used to evaluate the association between short- and long-term exposure to PM10 and high baPWV (≥the third quartile of baPWV, 1,534 cm/s) using logistic regression models. Additional subgroup analyses were conducted according to age, sex, obesity (body mass index ≥25.0 kg/m2), and comorbidities such as metabolic syndrome. @*Results@#No statistically significant associations were identified between short-term and long-term exposure to PM10 and baPWV in any of the subjects and subgroups. A 10-μg/m3 increase in the 2-day moving average of PM10 exposure was marginally associated with high baPWV in non-obese subjects (odds ratio, 1.059; P=0.058). This association in non-obese subjects was significantly different from that in obese subjects (P=0.038). @*Conclusion@#This study did not show statistically significant associations between short-term and long-term exposure to PM10 and baPWV in apparently healthy subjects. With short-term exposure to PM10, non-obese subjects showed a marginally unfavorable association with baPWV. Further studies are necessary to validate and elucidate the mechanism underlying the effect of PM10 on baPWV.

Effects of the conditions of microarc oxidation and hydrothermal treatments on the formation of micro-nano hybrid surface on titanium / 대한치과재료학회지

The effects of the conditions of microarc oxidation (MAO) and hydrothermal treatments on the formation of micro-nano hybrid surface on titanium has been studied. Titanium metals were microarc oxidized using the electrolyte containing Ca and P ions for 30, 60, 120, 180, and 240 s, respectively. These MAO-treated specimens were hydrothermally treated using alkaline solution (HT-treatment) or P-containing alkaline solution (HTP-treatment). The porous morphology was appeared after MAO treatment for more than 60 s. The Ca and P ions in oxide layer were detected clearly after MAO treatment for 120 s, and their contents increased as MAO-treatment time increased. After hydrothermal treatment, micro-sized hydroxyapatite (HAp) and nano-sized TiO2 crystallites were formed on porous surfaces. The size of HAp crystallites formed by HTP-treatment was larger than that formed by HT-treatment, while the size of TiO2 crystallites showed the opposite tendency. Surface roughness of MAO-treated groups increased with MAO-treatment time. After hydrothermal treatment, the roughnesses of the specimens MAO-treated for 30 and 60 s decreased, while the roughness increased after MAO treatment for 120 s. The hydrophilicity of MAO-treated specimens increased with MAO-treatment time. The hydrophilicity of the specimens MAO-treated for 30 and 60 s decreased after hydrothermal treatment. However, the hydrophilicity of the specimens treated with MAO over 120 s and subsequent HT- or HTP- treatments increased with the formation of HAp on their surfaces.

Evaluation of Adherence to Guideline for Heart Failure with Reduced Ejection Fraction in Heart Failure with Preserved Ejection Fraction and with or without Atrial Fibrillation

Background@#This study evaluated the relationship between guideline adherence for heart failure (HF) with reduced ejection fraction (HFrEF) at discharge and relevant clinical outcomes in patients with acute HF with preserved ejection fraction (HFpEF) with or without atrial fibrillation (AF). @*Methods@#We analyzed Korean Acute Heart Failure Registry data for 707 patients with HFpEF with documented AF and 687 without AF. Guideline adherence was defined as good or poor according to the prescription of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, β-blockers, and mineralocorticoid receptor antagonists. Anticoagulation adherence was also incorporated for the AF group. @*Results@#Among patients with normal sinus rhythm, those with poor guideline adherence had a reduced prevalence of comorbidities and favorable clinical characteristics when compared with those with good guideline adherence. Using inverse probability of treatment weighting (IPTW) to address the bias of nonrandom treatment assignment, good adherence was associated with a poor 60-day composite endpoint in the multivariable Cox model (weighted hazard ratio [wHR], 1.74; 95% confidence interval [CI], 1.01–3.00; P = 0.045). For patients with AF, baseline clinical characteristics were similar according to the degree of adherence. The IPTW-adjusted analysis indicated that good adherence was significantly associated with the 60-day composite endpoint (wHR, 0.47; 95% CI, 0.27–0.79; P = 0.005). In the analysis excluding warfarin, good adherence was associated with 60-day rehospitalization (wHR, 0.60; 95% CI, 0.37–0.98; P = 0.040), 1-year re-hospitalization (wHR, 0.67; 95% CI, 0.48–0.93; P = 0.018), and the composite endpoint (wHR, 0.77; 95% CI, 0.59–0.99; P = 0.041). @*Conclusion@#Our findings indicate that good adherence to guidelines for HFrEF is associated with a better 60-day composite endpoint in patients with HFpEF with AF.

Short- and Long-Term Exposure to Particulate Matter and Pulse Wave Velocity / 가정의학회지

Background@#In hemodialysis patients, brachial-ankle pulse wave velocity (baPWV) levels are affected by particulate matter with an aerodynamic diameter of 10 μm or less (PM10). We conducted this study to determine whether there is an association between short- and long-term PM10 exposure and baPWV in apparently healthy adults aged 40 years and older. @*Methods@#A total of 1,628 subjects who underwent health examinations between 2006 and 2009 were included in the study. On the basis of the day of medical screening, the 1–3-day and 365-day moving averages of PM10 concentrations were used to evaluate the association between short- and long-term exposure to PM10 and high baPWV (≥the third quartile of baPWV, 1,534 cm/s) using logistic regression models. Additional subgroup analyses were conducted according to age, sex, obesity (body mass index ≥25.0 kg/m2), and comorbidities such as metabolic syndrome. @*Results@#No statistically significant associations were identified between short-term and long-term exposure to PM10 and baPWV in any of the subjects and subgroups. A 10-μg/m3 increase in the 2-day moving average of PM10 exposure was marginally associated with high baPWV in non-obese subjects (odds ratio, 1.059; P=0.058). This association in non-obese subjects was significantly different from that in obese subjects (P=0.038). @*Conclusion@#This study did not show statistically significant associations between short-term and long-term exposure to PM10 and baPWV in apparently healthy subjects. With short-term exposure to PM10, non-obese subjects showed a marginally unfavorable association with baPWV. Further studies are necessary to validate and elucidate the mechanism underlying the effect of PM10 on baPWV.

Effects of the conditions of microarc oxidation and hydrothermal treatments on the formation of micro-nano hybrid surface on titanium / 대한치과재료학회지

The effects of the conditions of microarc oxidation (MAO) and hydrothermal treatments on the formation of micro-nano hybrid surface on titanium has been studied. Titanium metals were microarc oxidized using the electrolyte containing Ca and P ions for 30, 60, 120, 180, and 240 s, respectively. These MAO-treated specimens were hydrothermally treated using alkaline solution (HT-treatment) or P-containing alkaline solution (HTP-treatment). The porous morphology was appeared after MAO treatment for more than 60 s. The Ca and P ions in oxide layer were detected clearly after MAO treatment for 120 s, and their contents increased as MAO-treatment time increased. After hydrothermal treatment, micro-sized hydroxyapatite (HAp) and nano-sized TiO2 crystallites were formed on porous surfaces. The size of HAp crystallites formed by HTP-treatment was larger than that formed by HT-treatment, while the size of TiO2 crystallites showed the opposite tendency. Surface roughness of MAO-treated groups increased with MAO-treatment time. After hydrothermal treatment, the roughnesses of the specimens MAO-treated for 30 and 60 s decreased, while the roughness increased after MAO treatment for 120 s. The hydrophilicity of MAO-treated specimens increased with MAO-treatment time. The hydrophilicity of the specimens MAO-treated for 30 and 60 s decreased after hydrothermal treatment. However, the hydrophilicity of the specimens treated with MAO over 120 s and subsequent HT- or HTP- treatments increased with the formation of HAp on their surfaces.

Evaluation of Adherence to Guideline for Heart Failure with Reduced Ejection Fraction in Heart Failure with Preserved Ejection Fraction and with or without Atrial Fibrillation

Background@#This study evaluated the relationship between guideline adherence for heart failure (HF) with reduced ejection fraction (HFrEF) at discharge and relevant clinical outcomes in patients with acute HF with preserved ejection fraction (HFpEF) with or without atrial fibrillation (AF). @*Methods@#We analyzed Korean Acute Heart Failure Registry data for 707 patients with HFpEF with documented AF and 687 without AF. Guideline adherence was defined as good or poor according to the prescription of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, β-blockers, and mineralocorticoid receptor antagonists. Anticoagulation adherence was also incorporated for the AF group. @*Results@#Among patients with normal sinus rhythm, those with poor guideline adherence had a reduced prevalence of comorbidities and favorable clinical characteristics when compared with those with good guideline adherence. Using inverse probability of treatment weighting (IPTW) to address the bias of nonrandom treatment assignment, good adherence was associated with a poor 60-day composite endpoint in the multivariable Cox model (weighted hazard ratio [wHR], 1.74; 95% confidence interval [CI], 1.01–3.00; P = 0.045). For patients with AF, baseline clinical characteristics were similar according to the degree of adherence. The IPTW-adjusted analysis indicated that good adherence was significantly associated with the 60-day composite endpoint (wHR, 0.47; 95% CI, 0.27–0.79; P = 0.005). In the analysis excluding warfarin, good adherence was associated with 60-day rehospitalization (wHR, 0.60; 95% CI, 0.37–0.98; P = 0.040), 1-year re-hospitalization (wHR, 0.67; 95% CI, 0.48–0.93; P = 0.018), and the composite endpoint (wHR, 0.77; 95% CI, 0.59–0.99; P = 0.041). @*Conclusion@#Our findings indicate that good adherence to guidelines for HFrEF is associated with a better 60-day composite endpoint in patients with HFpEF with AF.

Structural basis for broad coronavirus neutralization

Three highly pathogenic {beta}-coronaviruses crossed the animal-to-human species barrier in the past two decades: SARS-CoV, MERS-CoV and SARS-CoV-2. SARS-CoV-2 has infected more than 64 million people worldwide, claimed over 1.4 million lives and is responsible for the ongoing COVID-19 pandemic. We isolated a monoclonal antibody, termed B6, cross-reacting with eight {beta}-coronavirus spike glycoproteins, including all five human-infecting {beta}-coronaviruses, and broadly inhibiting entry of pseudotyped viruses from two coronavirus lineages. Cryo-electron microscopy and X-ray crystallography characterization reveal that B6 binds to a conserved cryptic epitope located in the fusion machinery and indicate that antibody binding sterically interferes with spike conformational changes leading to membrane fusion. Our data provide a structural framework explaining B6 cross-reactivity with {beta}-coronaviruses from three lineages along with proof-of-concept for antibody-mediated broad coronavirus neutralization elicited through vaccination. This study unveils an unexpected target for next-generation structure-guided design of a pan-coronavirus vaccine.

De novo design of picomolar SARS-CoV-2 miniprotein inhibitors

We used two approaches to design proteins with shape and chemical complementarity to the receptor binding domain (RBD) of SARS-CoV-2 Spike protein near the binding site for the human ACE2 receptor. Scaffolds were built around an ACE2 helix that interacts with the RBD, or de novo designed scaffolds were docked against the RBD to identify new binding modes. In both cases, designed sequences were optimized first in silico and then experimentally for target binding, folding and stability. Nine designs bound the RBD with affinities ranging from 100pM to 10nM, and blocked bona fide SARS-CoV-2 infection of Vero E6 cells with IC50 values ranging from 35 pM to 35 nM; the most potent of these -- 56 and 64 residue hyperstable proteins made using the second approach -- are roughly six times more potent on a per mass basis (IC50 ~ 0.23 ng/ml) than the best monoclonal antibodies reported thus far. Cryo-electron microscopy structures of the SARS-CoV-2 spike ectodomain trimer in complex with the two most potent minibinders show that the structures of the designs and their binding interactions with the RBD are nearly identical to the computational models, and that all three RBDs in a single Spike protein can be engaged simultaneously. These hyperstable minibinders provide promising starting points for new SARS-CoV-2 therapeutics, and illustrate the power of computational protein design for rapidly generating potential therapeutic candidates against pandemic threats.

Structural and functional analysis of a potent sarbecovirus neutralizing antibody

SARS-CoV-2 is a newly emerged coronavirus responsible for the current COVID-19 pandemic that has resulted in more than one million infections and 73,000 deaths1,2. Vaccine and therapeutic discovery efforts are paramount to curb the pandemic spread of this zoonotic virus. The SARS-CoV-2 spike (S) glycoprotein promotes entry into host cells and is the main target of neutralizing antibodies. Here we describe multiple monoclonal antibodies targeting SARS-CoV-2 S identified from memory B cells of a SARS survivor infected in 2003. One antibody, named S309, potently neutralizes SARS-CoV-2 and SARS-CoV pseudoviruses as well as authentic SARS-CoV-2 by engaging the S receptor-binding domain. Using cryo-electron microscopy and binding assays, we show that S309 recognizes a glycan-containing epitope that is conserved within the sarbecovirus subgenus, without competing with receptor attachment. Antibody cocktails including S309 along with other antibodies identified here further enhanced SARS-CoV-2 neutralization and may limit the emergence of neutralization-escape mutants. These results pave the way for using S309 and S309-containing antibody cocktails for prophylaxis in individuals at high risk of exposure or as a post-exposure therapy to limit or treat severe disease.

Structure, function and antigenicity of the SARS-CoV-2 spike glycoprotein

The recent emergence of a novel coronavirus associated with an ongoing outbreak of pneumonia (Covid-2019) resulted in infections of more than 72,000 people and claimed over 1,800 lives. Coronavirus spike (S) glycoprotein trimers promote entry into cells and are the main target of the humoral immune response. We show here that SARS-CoV-2 S mediates entry in VeroE6 cells and in BHK cells transiently transfected with human ACE2, establishing ACE2 as a functional receptor for this novel coronavirus. We further demonstrate that the receptor-binding domains of SARS-CoV-2 S and SARS-CoV S bind with similar affinities to human ACE2, which correlates with the efficient spread of SARS-CoV-2 among humans. We found that the SARS-CoV-2 S glycoprotein harbors a furin cleavage site at the boundary between the S1/S2 subunits, which is processed during biogenesis and sets this virus apart from SARS-CoV and other SARS-related CoVs. We determined a cryo-electron microscopy structure of the SARS-CoV-2 S ectodomain trimer, demonstrating spontaneous opening of the receptor-binding domain, and providing a blueprint for the design of vaccines and inhibitors of viral entry. Finally, we demonstrate that SARS-CoV S murine polyclonal sera potently inhibited SARS-CoV-2 S-mediated entry into target cells, thereby indicating that cross-neutralizing antibodies targeting conserved S epitopes can be elicited upon vaccination.