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1.
Frontiers in cardiovascular medicine ; 9, 2022.
Article in English | EuropePMC | ID: covidwho-2057652

ABSTRACT

Background Electrocardiography (ECG) plays a very important role in various cardiovascular diseases and elevated D-dimer in serum associated with thrombosis. In patients with coronavirus disease 2019 (COVID-19), immense pieces of evidence showed that ECG abnormalities or elevated D-dimer in serum occurred frequently. However, it remains unclear whether ECG abnormalities combined with elevated D-dimer could be a new risk predictor in patients with COVID-19. Methods and results This retrospective cohort study enrolled 416 patients with COVID-19 at Wuhan Tongji Hospital from 1 February to 20 March 2020. ECG manifestations, D-dimer levels, and in-hospital deaths were recorded for all patients. Logistic regression analysis was performed to examine the association between ECG manifestations and in-hospital mortality in patients with elevated D-dimer levels. In patients hospitalized for COVID-19, ST-T abnormalities (34.3%) were the most frequent ECG manifestations, whereas sinus tachycardia (ST) (13.3%) and atrial arrhythmias with rapid rhythms (8.5%) were the two most common cardiac arrhythmias. Compared to severely ill patients with COVID-19, ST-T abnormalities, ST and atrial arrhythmias (p<0.001) with rapid rhythms, D-dimer levels, and in-hospital deaths were significantly more frequent in critically ill patients with COVID-19. Moreover, elevated D-dimer levels were observed in all the patients who died. In the subgroup of 303 patients with elevated serum D-dimer levels, the patient's age, the incidence of ST-T abnormalities, ST, atrial fibrillation (AF), and atrial premature beat were significantly higher than those in the non-elevated D-dimer subgroup. Multivariate logistic regression analysis further revealed that ST and AF were risk factors for in-hospital mortality in COVID-19 patients with elevated D-dimer levels. Conclusions ECG abnormalities and elevated D-dimer levels were associated with a higher risk of critical illness and death in patients hospitalized for COVID-19. ECG abnormalities, including ST and AF, combined with elevated D-dimer levels, can be used to predict death in COVID-19.

2.
Nat Commun ; 13(1): 4615, 2022 08 08.
Article in English | MEDLINE | ID: covidwho-2036813

ABSTRACT

Understanding the impact of age on vaccinations is essential for the design and delivery of vaccines against SARS-CoV-2. Here, we present findings from a comprehensive analysis of multiple compartments of the memory immune response in 312 individuals vaccinated with the BNT162b2 SARS-CoV-2 mRNA vaccine. Two vaccine doses induce high antibody and T cell responses in most individuals. However, antibody recognition of the Spike protein of the Delta and Omicron variants is less efficient than that of the ancestral Wuhan strain. Age-stratified analyses identify a group of low antibody responders where individuals ≥60 years are overrepresented. Waning of the antibody and cellular responses is observed in 30% of the vaccinees after 6 months. However, age does not influence the waning of these responses. Taken together, while individuals ≥60 years old take longer to acquire vaccine-induced immunity, they develop more sustained acquired immunity at 6 months post-vaccination. A third dose strongly boosts the low antibody responses in the older individuals against the ancestral Wuhan strain, Delta and Omicron variants.


Subject(s)
COVID-19 , Viral Vaccines , Aged , Antibodies, Viral , Antibody Formation , BNT162 Vaccine , COVID-19/prevention & control , COVID-19 Vaccines , Humans , Middle Aged , SARS-CoV-2 , Vaccination , Vaccines, Synthetic , mRNA Vaccines
3.
Clin Transl Immunology ; 11(8): e1403, 2022.
Article in English | MEDLINE | ID: covidwho-2003593

ABSTRACT

Objective: Despite the high vaccine efficacy of mRNA COVID-19 vaccines, there are individuals who developed excessive reactogenic and/or allergic responses after the first mRNA dose and were considered ineligible for further mRNA doses. CoronaVac, an inactivated SARS-CoV-2 vaccine, is recommended in Singapore as an alternative. Methods: Individuals, ineligible for further mRNA vaccines (BNT162b2 or mRNA-1273) because of excessive reactive responses to prime mRNA vaccination, were recruited and offered two doses of CoronaVac as booster vaccination 38-224 days post their mRNA vaccine dose. Individuals who did not develop any excessive reactive responses after the prime mRNA vaccination were also recruited and given another mRNA vaccine as booster vaccination. Blood samples were collected at days 0, 21 and 90 post first CoronaVac dose and mRNA dose, respectively, for analysis. Results: We showed that two CoronaVac booster doses induced specific immunity in these mRNA vaccine-primed individuals. Although the spike-specific antibody response was lower, their memory B cell response against the receptor-binding domain (RBD) of the spike protein was similar, compared with individuals who received two BNT162b2 injections. The spike-specific memory T cell response also increased following CoronaVac booster doses. However, specific immunity against the Omicron variant was low, similar to individuals with two BNT162b2 doses. Conclusion: Our findings showed that while mRNA vaccine-primed individuals can opt for two subsequent doses of CoronaVac, an additional dose may be necessary to achieve protection, especially against newly emerging immune escape variants such as Omicron.

4.
Transbound Emerg Dis ; 69(4): 1782-1793, 2022 Jul.
Article in English | MEDLINE | ID: covidwho-1973736

ABSTRACT

Since 2010, several duck Tembusu viruses (DTMUVs) have been isolated from infected ducks in China, and these virus strains have undergone extensive variation over the years. Although the infection rate is high, the mortality rate is usually relatively low-~5%-30%; however, since fall 2019, an infectious disease similar to DTMUV infection but with a high mortality rate of ~50% in goslings has been prevalent in Anhui Province, China. The present study identified a new Tembusu virus, designated DTMUV/Goose/China/2019/AQ-19 (AQ-19), that is believed to be responsible for the noticeably high mortality in goslings. To investigate the genetic variation of this strain, its entire genome was sequenced and analysed for specific variations, and goslings and mice were challenged with the isolated virus to investigate its pathogenicity. The AQ-19 genome shared only 94.3%-96.9% and 90.9% nucleotide identity with other Chinese and Malaysian DTMUVs, respectively; however, AQ-19 has high homology with Thailand DTMUVs (97.2%-98.1% nucleotide identity). Phylogenetic analysis of the E gene revealed that AQ-19 and most of Thailand DTMUVs form a branch separate from any of the previously reported DTMUV strains in China. After the challenge, some goslings and mice showed typical clinical signs of DTMUV, particularly severe neurological dysfunction. AQ-19 has high virulence in goslings and mice, resulting in 60% and 70% mortality through intramuscular and intracerebral routes, respectively. Pathological examination revealed severe histological lesions in the brain and liver of the infected goslings and mice. Taken together, these results demonstrated the emergence of a novel Tembusu virus with high virulence circulating in goslings in China for the first time, and our findings highlight the high genetic diversity of DTMUVs in China. Further study of the pathogenicity and host range of this novel Tembusu virus is particularly important.


Subject(s)
Flavivirus Infections , Flavivirus , Poultry Diseases , Rodent Diseases , Animals , China/epidemiology , Ducks , Flavivirus/genetics , Flavivirus Infections/epidemiology , Flavivirus Infections/veterinary , Geese , Mice , Nucleotides , Phylogeny , Poultry Diseases/epidemiology
5.
J Integr Med ; 20(6): 561-574, 2022 Nov.
Article in English | MEDLINE | ID: covidwho-1966871

ABSTRACT

OBJECTIVE: Severe cases of coronavirus disease 2019 (COVID-19) are expected to have a worse prognosis than mild cases. Shenhuang Granule (SHG) has been shown to be a safe and effective treatment for severe COVID-19 in a previous randomized clinical trial, but the active chemical constituents and underlying mechanisms of action remain unknown. The goal of this study is to explore the chemical basis and mechanisms of SHG in the treatment of severe COVID-19, using network pharmacology. METHODS: Ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry was employed to screen chemical constituents of SHG. Putative therapeutic targets were predicted by searching traditional Chinese medicine system pharmacology database and analysis platform, SwissTargetPrediction, and Gene Expression Omnibus (GEO) databases. The target protein-protein interaction network and enrichment analysis were performed to investigate the hub genes and presumptive mechanisms. Molecular docking and molecular dynamics simulations were used to verify the stability and interaction between the key chemical constituents of SHG and COVID-19 protein targets. RESULTS: Forty-five chemical constituents of SHG were identified along with 131 corresponding therapeutic targets, including hub genes such as HSP90AA1, MMP9, CXCL8, PTGS2, IFNG, DNMT1, TYMS, MDM2, HDAC3 and ABCB1. Functional enrichment analysis indicated that SHG mainly acted on the neuroactive ligand-receptor interaction, calcium signaling pathway and cAMP signaling pathway. Molecular docking showed that the key constituents had a good affinity with the severe acute respiratory syndrome coronavirus 2 protein targets. Molecular dynamics simulations indicated that ginsenoside Rg4 formed a stable protein-ligand complex with helicase. CONCLUSION: Multiple components of SHG regulated multiple targets to inhibit virus invasion and cytokine storm through several signaling pathways; this provides a scientific basis for clinical applications and further experiments.


Subject(s)
COVID-19 , Drugs, Chinese Herbal , Humans , COVID-19/drug therapy , Molecular Docking Simulation , Ligands , Network Pharmacology , Drugs, Chinese Herbal/pharmacology , Drugs, Chinese Herbal/therapeutic use , Drugs, Chinese Herbal/chemistry , Medicine, Chinese Traditional
6.
Sci Signal ; 15(715): eabh0068, 2022 01 04.
Article in English | MEDLINE | ID: covidwho-1741564

ABSTRACT

The transcription regulator ID2 plays an essential role in the development and differentiation of immune cells. Here, we report that ID2 also negatively regulates antiviral innate immune responses. During viral infection of human epithelial cells, ID2 bound to TANK-binding kinase 1 (TBK1) and to inhibitor of nuclear factor κB kinase ε (IKKε). These interactions inhibited the recruitment and activation of interferon (IFN) regulatory factor 3 (IRF3) by TBK1 or IKKε, leading to a reduction in the expression of IFN-ß1 (IFNB1). IFN-ß induced the nuclear export of ID2 to form a negative feedback loop. Knocking out ID2 in human cells enhanced innate immune responses and suppressed infection by different viruses, including SARS-CoV-2. Mice with a myeloid-specific deficiency of ID2 produced more IFN-α in response to viral infection and were more resistant to viral infection than wild-type mice. Our findings not only establish ID2 as a modulator of IRF3 activation induced by TBK1 and/or IKKε but also introduce a mechanism for cross-talk between innate immunity and cell development and differentiation.


Subject(s)
COVID-19 , I-kappa B Kinase , Animals , Antiviral Agents , Humans , I-kappa B Kinase/genetics , I-kappa B Kinase/metabolism , Immunity, Innate , Inhibitor of Differentiation Protein 2 , Interferon Regulatory Factor-3/genetics , Interferon Regulatory Factor-3/metabolism , Mice , Phosphorylation , SARS-CoV-2
7.
MAbs ; 14(1): 2040350, 2022.
Article in English | MEDLINE | ID: covidwho-1740684

ABSTRACT

The emergence of escape variants of SARS-CoV-2 carrying mutations in the spike protein poses a challenge for therapeutic antibodies. Here, we show that through the comprehensive engineering of the variable region of the neutralizing monoclonal antibody 5A6, the engineered antibody, 5A6CCS1, is able to neutralize SARS-CoV-2 variants that escaped neutralization by the original 5A6 antibody. In addition to the improved affinity against variants, 5A6CCS1 was also optimized to achieve high solubility and low viscosity, enabling a high concentration formulation for subcutaneous injection. In cynomolgus monkeys, 5A6CCS1 showed a long plasma half-life and good subcutaneous bioavailability through engineering of the variable and constant region. These data demonstrate that 5A6CCS1 is a promising antibody for development against SARS-CoV-2 and highlight the importance of antibody engineering as a potential method to counteract escape variants.


Subject(s)
COVID-19 , Spike Glycoprotein, Coronavirus , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/therapy , Humans , Membrane Glycoproteins , Neutralization Tests , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Viral Envelope Proteins
8.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-312660

ABSTRACT

[Background] On January 7, 2020, the novel coronavirus named "COVID-19" aroused worldwide concern was identified by Chinese scientists. Many related research works were developed for the emerging, rapidly evolving situation of this epidemic. This study aimed to analyze the research literatures on SARS, MERS and COVID-19 to retrieve important information for virologists, epidemiologist and policy decision makers. [Methods] In this study, we collected data from multi data sources and compared bibliometrics indices among COVID-19, Severe Acute Respiratory Syndrome (SARS), and Middle East Respiratory Syndrome (MERS) up to March 25, 2020. In purpose to extract data in corresponding quantity and scale, the volume of search results will be balance with the limitation of publication years. For further analysis, we extracted 1,480 documents from 1,671 candidates with Natural Language Processing technologies. [Results] In total, 13,945 research literatures of 7 datasets were selected for analysis. Unlike other topics, research passion on epidemic may reach its peak at the first year the outbreak happens. The document type distribution of SARS, MERS and COVID-19 are nearly the same (less than 6 point difference for each type), however, there were notable growth in the research qualities during these three epidemics (3.68, 6.63 and 11.35 for Field-Weighted Citation Impact scores). Asian countries has less international collaboration (less than 35.1\%) than the Occident (more than 49.5\%), which should be noticed as same as research itself. [Conclusions] We found that research passion on epidemics may always reach its peak at the first year after outburst, however, the peak of research on MERS appeared at the third year because of its outburst of reproduction in 2015. For the research quality, although we did better in research qualities than before especially on COVID-19, research on epidemics not started from our own country should not be looked down. Another important effective strategy for enhancing epidemic prevention for China and other Asian countries is to continue strengthening international collaboration.

9.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-311275

ABSTRACT

Early detection of infections is crucial to limit the spread of coronavirus 2019 disease (COVID-19). Here, we developed a flow cytometry-based assay to detect SARS-CoV-2 Spike protein (S protein) antibodies in COVID-19 patients. The assay detected specific IgM and IgG in COVID-19 patients and also the acquisition of all IgG subclasses, with IgG1 being the most dominant. The antibody response was significantly higher at a later stage of the infection. Furthermore, asymptomatic COVID-19 patients also developed specific IgM and IgG, with IgG1 as the most dominant subclass. Although the antibody levels were lower in asymptomatic infections, the assay was highly sensitive and detected 97% of asymptomatic infections. These findings demonstrated that the assay could be used for serological analysis of symptomatic patients, and also as a sensitive tool to detect asymptomatic infections, which may go undetected.Funding: Biomedical Research Council (BMRC), the A*ccelerate GAP-funded project (ACCL/19-GAP064-R20H-H) from Agency of Science, Technology and Research (A*STAR), and National Medical Research Council (NMRC) COVID-19 Research fund (COVID19RF-001, COVID-19RF-007, COVID-19RF-60).Conflict of Interest: The authors declare no competing interests.Ethical Approval: The study design and protocols for COVID-19, recovered SARS and seasonal human CoV patient cohorts were approved by National Healthcare Group (NHG) Domain Specific Review Board (DSRB) and performed, following ethical guidelines in the approved studies 2012/00917, 2020/00091 and 2020/00076 respectively. Healthy donor samples were collected in accordance with approved studies 2017/2806 and NUS IRB 04-140. Written informed consent was obtained from participants in accordance with the Declaration of Helsinki for Human Research.

10.
EMBO Mol Med ; 14(3): e15227, 2022 03 07.
Article in English | MEDLINE | ID: covidwho-1643965

ABSTRACT

The SARS-CoV-2 Delta (B.1.617.2) variant is capable of infecting vaccinated persons. An open question remains as to whether deficiencies in specific vaccine-elicited immune responses result in susceptibility to vaccine breakthrough infection. We investigated 55 vaccine breakthrough infection cases (mostly Delta) in Singapore, comparing them against 86 vaccinated close contacts who did not contract infection. Vaccine breakthrough cases showed lower memory B cell frequencies against SARS-CoV-2 receptor-binding domain (RBD). Compared to plasma antibodies, antibodies secreted by memory B cells retained a higher fraction of neutralizing properties against the Delta variant. Inflammatory cytokines including IL-1ß and TNF were lower in vaccine breakthrough infections than primary infection of similar disease severity, underscoring the usefulness of vaccination in preventing inflammation. This report highlights the importance of memory B cells against vaccine breakthrough and suggests that lower memory B cell levels may be a correlate of risk for Delta vaccine breakthrough infection.


Subject(s)
COVID-19 , COVID-19/prevention & control , COVID-19 Vaccines , Humans , SARS-CoV-2
11.
JMIR Perioper Med ; 4(2): e30473, 2021 Oct 06.
Article in English | MEDLINE | ID: covidwho-1523625

ABSTRACT

BACKGROUND: The Enhanced Recovery After Surgery (ERAS) protocol has been recently extended to hepatopancreatobiliary (HPB) surgery, with excellent outcomes reported. Early mobilization is an essential facet of the ERAS protocol, but compliance has been reported to be poor. We recently reported our success in a 6-month clinical practice improvement program (CPIP) for early postoperative mobilization. During the COVID-19 pandemic, we experienced reduced staffing and resource availability, which can make CPIP sustainability difficult. OBJECTIVE: We report outcomes at 1 year following the implementation of our CPIP to improve postoperative mobilization in patients undergoing major HPB surgery during the COVID-19 pandemic. METHODS: We divided our study into 4 phases-phase 1: before CPIP implementation (January to April 2019); phase 2: CPIP implementation (May to September 2019); phase 3: post-CPIP implementation but prior to the COVID-19 pandemic (October 2019 to March 2020); and phase 4: post-CPIP implementation and during the pandemic (April 2020 to September 2020). Major HPB surgery was defined as any surgery on the liver, pancreas, and biliary system with a duration of >2 hours and with an anticipated blood loss of ≥500 ml. Study variables included length of hospital stay, distance ambulated on postoperative day (POD) 2, morbidity, balance measures (incidence of fall and accidental dislodgement of drains), and reasons for failure to achieve targets. Successful mobilization was defined as the ability to sit out of bed for >6 hours on POD 1 and ambulate ≥30 m on POD 2. The target mobilization rate was ≥75%. RESULTS: A total of 114 patients underwent major HPB surgery from phases 2 to 4 of our study, with 33 (29.0%), 45 (39.5%), and 36 (31.6%) patients in phases 2, 3, and 4, respectively. No baseline patient demographic data were collected for phase 1 (pre-CPIP implementation). The majority of the patients were male (n=79, 69.3%) and underwent hepatic surgery (n=92, 80.7%). A total of 76 (66.7%) patients underwent ON-Q PainBuster insertion intraoperatively. The median mobilization rate was 22% for phase 1, 78% for phases 2 and 3 combined, and 79% for phase 4. The mean pain score was 2.7 (SD 1.0) on POD 1 and 1.8 (SD 1.5) on POD 2. The median length of hospitalization was 6 days (IQR 5-11.8). There were no falls or accidental dislodgement of drains. Six patients (5.3%) had pneumonia, and 21 (18.4%) patients failed to ambulate ≥30 m on POD 2 from phases 2 to 4. The most common reason for failure to achieve the ambulation target was pain (6/21, 28.6%) and lethargy or giddiness (5/21, 23.8%). CONCLUSIONS: This follow-up study demonstrates the sustainability of our CPIP in improving early postoperative mobilization rates following major HPB surgery 1 year after implementation, even during the COVID-19 pandemic. Further large-scale, multi-institutional prospective studies should be conducted to assess compliance and determine its sustainability.

12.
NPJ Vaccines ; 6(1): 125, 2021 Oct 25.
Article in English | MEDLINE | ID: covidwho-1483131

ABSTRACT

The rapid spreading of SARS-CoV-2 variants B.1.1.7 originated from the United Kingdom and B.1.351 from South Africa has contributed to the second wave of COVID-19 cases in the respective countries and also around the world. In this study, we employed advanced biochemical and virological methodologies to evaluate the impact of Spike mutations of these strains on the degree of protection afforded by humoral immune responses following natural infection of the ancestral SARS-CoV-2 strain during the early stages of the outbreak. We found that antibody-mediated neutralization activity was partially reduced for B.1.1.7 variant and significantly attenuated for the B.1.351 strain. We also found that mutations outside the receptor-binding domain (RBD) can strongly influence antibody binding and neutralization, cautioning the use of solely RBD mutations in evaluating vaccine efficacy. These findings highlight an urgent need to develop new SARS-CoV-2 vaccines that are not based exclusively on the ancestral SARS-CoV-2 Spike gene sequence.

13.
Viruses ; 13(10)2021 09 30.
Article in English | MEDLINE | ID: covidwho-1481008

ABSTRACT

Measles virus (MeV) genotype B3 is one globally significant circulating genotype. Here, we present a systematic description of long-term evolutionary characterizations of the MeV genotype B3's hemagglutinin (H) gene in the elimination era. Our results show that the B3 H gene can be divided into two main sub-genotypes, and the highest intra-genotypic diversity was observed in 2004. MeV genotype B3's H gene diverged in 1976; its overall nucleotide substitution rate is estimated to be 5.697 × 10-4 substitutions/site/year, and is slowing down. The amino acid substitution rate of genotype B3's H gene is also decreasing, and the mean effective population size has been in a downward trend since 2000. Selection pressure analysis only recognized a few sites under positive selection, and the number of positive selection sites is getting smaller. All of these observations may reveal that genotype B3's H gene is not under strong selection pressure, and is becoming increasingly conservative. MeV H-gene or whole-genome sequencing should be routine, so as to better elucidate the molecular epidemiology of MeV in the future.


Subject(s)
Hemagglutinins, Viral/genetics , Measles virus/genetics , China , Evolution, Molecular , Genetic Variation/genetics , Genotype , Hemagglutinins/genetics , Humans , Measles/virology , Molecular Epidemiology/methods , Phylogeny , Sequence Analysis, DNA/methods
15.
Glob Health Res Policy ; 6(1): 22, 2021 07 06.
Article in English | MEDLINE | ID: covidwho-1296630

ABSTRACT

BACKGROUND: China has increasingly emerged as an important player in global health. However, compared to developed countries, China still lacks a sufficient health workforce for global health engagement with the necessary competencies required. The world has recognized that to solve global health issues, the role of China needs to be strengthened. The priorities for the deployment of the Chinese workforce in global health remain unclear. This study aims to identify the priorities of the deployment of Chinese global health workforce by exploring the core competencies for Chinese global health workforce, factors influencing the deployment and the approach of deployment. METHODS: Quantitative descriptive statistical analysis was applied to analyze the quantitative data. A total of 148 key respondents from 10 provinces in China conducting global health projects over the last 3 years were selected as the study subjects. A structured questionnaire was developed to collect the data on four aspects, including general information, core competencies, factors influencing deployment, and mode of deployment. The questionnaire was distributed to the respondents through an online survey. All original data were exported to Microsoft Excel 2010 to calculate the frequencies and percentages of each option. A descriptive analysis was carried out of the priorities of deployment of the Chinese global health workforce. RESULTS: More than half of the respondents (51.4%, 76/148) regarded "communication" as the most important competency of the Chinese global health workforce, while a large proportion of participants from Chinese embassies (50.0%, 6/12) and international organizations (75.0%, 12/16) believed that "professional skills" were paramount. In addition, 58.1% (86/148) of the participants agreed that incentive factors (salary, professional position, etc.) were the main factors that influenced deployment, whereas 75% (12/16) of participants from international organizations emphasized "security" as the most important determinant. In addition, 60.8% (90/148) of the participants thought that the deployment of staff should be based on the needs of the global health project implementation. CONCLUSIONS: This study highlights the deployment priorities of the Chinese global health workforce, including strengthening communication and professional skills, focusing on personal security and incentives, and catering to the project implementation. This study also highlights the importance of Chinese agencies in developing global health mindsets through global health practices and proactive integration within the global community.


Subject(s)
Global Health , Health Workforce , China , Humans , Surveys and Questionnaires , Workforce
16.
Cell ; 184(12): 3192-3204.e16, 2021 06 10.
Article in English | MEDLINE | ID: covidwho-1222850

ABSTRACT

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is initiated by binding of the viral Spike protein to host receptor angiotensin-converting enzyme 2 (ACE2), followed by fusion of viral and host membranes. Although antibodies that block this interaction are in emergency use as early coronavirus disease 2019 (COVID-19) therapies, the precise determinants of neutralization potency remain unknown. We discovered a series of antibodies that potently block ACE2 binding but exhibit divergent neutralization efficacy against the live virus. Strikingly, these neutralizing antibodies can inhibit or enhance Spike-mediated membrane fusion and formation of syncytia, which are associated with chronic tissue damage in individuals with COVID-19. As revealed by cryoelectron microscopy, multiple structures of Spike-antibody complexes have distinct binding modes that not only block ACE2 binding but also alter the Spike protein conformational cycle triggered by ACE2 binding. We show that stabilization of different Spike conformations leads to modulation of Spike-mediated membrane fusion with profound implications for COVID-19 pathology and immunity.


Subject(s)
Antibodies, Neutralizing/chemistry , Giant Cells/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/immunology , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/metabolism , Antigen-Antibody Complex/chemistry , Antigen-Antibody Complex/metabolism , Binding Sites , CHO Cells , COVID-19/pathology , COVID-19/virology , Cricetinae , Cricetulus , Cryoelectron Microscopy , Giant Cells/cytology , Humans , Membrane Fusion , Peptide Library , Protein Binding , Protein Domains , Protein Structure, Quaternary , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism
17.
EMBO Mol Med ; 13(6): e14045, 2021 06 07.
Article in English | MEDLINE | ID: covidwho-1219070

ABSTRACT

The immune responses and mechanisms limiting symptom progression in asymptomatic cases of SARS-CoV-2 infection remain unclear. We comprehensively characterized transcriptomic profiles, cytokine responses, neutralization capacity of antibodies, and cellular immune phenotypes of asymptomatic patients with acute SARS-CoV-2 infection to identify potential protective mechanisms. Compared to symptomatic patients, asymptomatic patients had higher counts of mature neutrophils and lower proportion of CD169+ expressing monocytes in the peripheral blood. Systemic levels of pro-inflammatory cytokines were also lower in asymptomatic patients, accompanied by milder pro-inflammatory gene signatures. Mechanistically, a more robust systemic Th2 cell signature with a higher level of virus-specific Th17 cells and a weaker yet sufficient neutralizing antibody profile against SARS-CoV-2 was observed in asymptomatic patients. In addition, asymptomatic COVID-19 patients had higher systemic levels of growth factors that are associated with cellular repair. Together, the data suggest that asymptomatic patients mount less pro-inflammatory and more protective immune responses against SARS-CoV-2 indicative of disease tolerance. Insights from this study highlight key immune pathways that could serve as therapeutic targets to prevent disease progression in COVID-19.


Subject(s)
COVID-19/pathology , Carrier State/immunology , Biomarkers/metabolism , Brain-Derived Neurotrophic Factor/metabolism , COVID-19/immunology , COVID-19/virology , Carrier State/pathology , Carrier State/virology , Cytokines/metabolism , Humans , Monocytes/cytology , Monocytes/immunology , Monocytes/metabolism , Neutrophils/cytology , Neutrophils/immunology , Neutrophils/metabolism , SARS-CoV-2/isolation & purification , Th17 Cells/cytology , Th17 Cells/immunology , Th17 Cells/metabolism , Transcriptome , Up-Regulation , Vascular Endothelial Growth Factor D/metabolism
18.
Virol Sin ; 36(5): 890-900, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1174013

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a devastating pandemic worldwide. Vaccines and antiviral drugs are the most promising candidates for combating this global epidemic, and scientists all over the world have made great efforts to this end. However, manipulation of the SARS-CoV-2 should be performed in the biosafety level 3 laboratory. This makes experiments complicated and time-consuming. Therefore, a safer system for working with this virus is urgently needed. Here, we report the construction of plasmid-based, non-infectious SARS-CoV-2 replicons with turbo-green fluorescent protein and/or firefly luciferase reporters by reverse genetics using transformation-associated recombination cloning in Saccharomyces cerevisiae. Replication of these replicons was achieved simply by direct transfection of cells with the replicon plasmids as evident by the expression of reporter genes. Using SARS-CoV-2 replicons, the inhibitory effects of E64-D and remdesivir on SARS-CoV-2 replication were confirmed, and the half-maximal effective concentration (EC50) value of remdesivir and E64-D was estimated by different quantification methods respectively, indicating that these SARS-CoV-2 replicons are useful tools for antiviral drug evaluation.


Subject(s)
COVID-19 , SARS-CoV-2 , Antiviral Agents/pharmacology , Drug Evaluation , Humans , Replicon , Virus Replication
19.
Cell Rep Med ; 2(2): 100193, 2021 02 16.
Article in English | MEDLINE | ID: covidwho-1069040

ABSTRACT

Early detection of infection is crucial to limit the spread of coronavirus disease 2019 (COVID-19). Here we develop a flow cytometry-based assay to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein antibodies in individuals with COVID-19. The assay detects specific immunoglobulin M (IgM), IgA, and IgG in individuals with COVID-19 and also acquisition of all IgG subclasses, with IgG1 being the most dominant. The antibody response is significantly higher at a later stage of infection. Furthermore, asymptomatic individuals with COVID-19 also develop specific IgM, IgA, and IgG, with IgG1 being the most dominant subclass. Although the antibody levels are lower in asymptomatic infection, the assay is highly sensitive and detects 97% of asymptomatic infections. These findings demonstrate that the assay can be used for serological analysis of symptomatic and asymptomatic infections, which may otherwise remain undetected.


Subject(s)
Antibodies, Viral/blood , COVID-19/pathology , Immunoglobulin Class Switching/physiology , Immunoglobulin G/blood , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/immunology , Antibodies, Viral/immunology , Asymptomatic Diseases , COVID-19/immunology , COVID-19/virology , Flow Cytometry , Humans , Immunoglobulin G/immunology , Immunologic Tests/methods , SARS-CoV-2/isolation & purification
20.
bioRxiv ; 2020 Jul 15.
Article in English | MEDLINE | ID: covidwho-920837

ABSTRACT

In vitro antibody selection against pathogens from naïve combinatorial libraries can yield various classes of antigen-specific binders that are distinct from those evolved from natural infection 1-4 . Also, rapid neutralizing antibody discovery can be made possible by a strategy that selects for those interfering with pathogen and host interaction 5 . Here we report the discovery of antibodies that neutralize SARS-CoV-2, the virus responsible for the COVID-19 pandemic, from a highly diverse naïve human Fab library. Lead antibody 5A6 blocks the receptor binding domain (RBD) of the viral spike from binding to the host receptor angiotensin converting enzyme 2 (ACE2), neutralizes SARS-CoV-2 infection of Vero E6 cells, and reduces viral replication in reconstituted human nasal and bronchial epithelium models. 5A6 has a high occupancy on the viral surface and exerts its neutralization activity via a bivalent binding mode to the tip of two neighbouring RBDs at the ACE2 interaction interface, one in the "up" and the other in the "down" position, explaining its superior neutralization capacity. Furthermore, 5A6 is insensitive to several spike mutations identified in clinical isolates, including the D614G mutant that has become dominant worldwide. Our results suggest that 5A6 could be an effective prophylactic and therapeutic treatment of COVID-19.

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