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1.
Viruses ; 12(7)2020 07 07.
Article in English | MEDLINE | ID: covidwho-639283

ABSTRACT

Standard precautions to minimize the risk of SARS-CoV-2 transmission implies that infected cell cultures and clinical specimens may undergo some sort of inactivation to reduce or abolish infectivity. We evaluated three heat inactivation protocols (56 °C-30 min, 60 °C-60 min and 92 °C-15 min) on SARS-CoV-2 using (i) infected cell culture supernatant, (ii) virus-spiked human sera (iii) and nasopharyngeal samples according to the recommendations of the European norm NF EN 14476-A2. Regardless of the protocol and the type of samples, a 4 Log10 TCID50 reduction was observed. However, samples containing viral loads > 6 Log10 TCID50 were still infectious after 56 °C-30 min and 60 °C-60 min, although infectivity was < 10 TCID50. The protocols 56 °C-30 min and 60 °C-60 min had little influence on the RNA copies detection, whereas 92 °C-15 min drastically reduced the limit of detection, which suggests that this protocol should be avoided for inactivation ahead of molecular diagnostics. Lastly, 56 °C-30 min treatment of serum specimens had a negligible influence on the results of IgG detection using a commercial ELISA test, whereas a drastic decrease in neutralizing titers was observed.


Subject(s)
Betacoronavirus , Containment of Biohazards/methods , Coronavirus Infections/virology , Pneumonia, Viral/virology , Serologic Tests/methods , Virus Inactivation , Antibodies, Neutralizing/immunology , Betacoronavirus/immunology , Containment of Biohazards/standards , Coronavirus Infections/diagnosis , Coronavirus Infections/prevention & control , Enzyme-Linked Immunosorbent Assay , Hot Temperature , Humans , Neutralization Tests , Pandemics/prevention & control , Pneumonia, Viral/diagnosis , Pneumonia, Viral/prevention & control , Serologic Tests/standards
2.
Tidsskr Nor Laegeforen ; 140(11)2020 08 18.
Article in English, Norwegian | MEDLINE | ID: covidwho-724631

ABSTRACT

BACKGROUND: Robust serological assays for SARS-CoV-2 are essential for determining prior infection and the suitability of donated convalescent plasma for plasma therapy. We compared two in-house and three commercial serological assays in a family cohort with SARS-CoV-2-infected members. CASE PRESENTATION: Three individuals in a family of five developed COVID-19 confirmed by PCR, following a trip abroad. Three to four weeks after the onset of symptoms, three commercial ELISAs and an in-house immunofluorescence test demonstrated antibodies to SARS-CoV-2. An in-house neutralisation test also demonstrated neutralising antibodies. INTERPRETATION: The in-house assays and one commercial assay gave congruent results, which were also consistent with the initial PCR and/or clinical evaluation, indicating prior infection in three of the five family members. The other commercial assays indicated possible infection in a fourth family member, but this result was likely due to cross-reactivity. The neutralising antibodies suggest complete or partial immunity against reinfection.


Subject(s)
Antibodies, Viral/immunology , Antibody Formation , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , Antibodies, Neutralizing/immunology , Betacoronavirus , Enzyme-Linked Immunosorbent Assay , Family Health , Fluorescent Antibody Technique , Humans , Neutralization Tests , Pandemics , Serologic Tests
3.
Clin Microbiol Rev ; 33(4)2020 09 16.
Article in English | MEDLINE | ID: covidwho-721176

ABSTRACT

Convalescent plasma (CP) therapy has been used since the early 1900s to treat emerging infectious diseases; its efficacy was later associated with the evidence that polyclonal neutralizing antibodies can reduce the duration of viremia. Recent large outbreaks of viral diseases for which effective antivirals or vaccines are still lacking has renewed the interest in CP as a life-saving treatment. The ongoing COVID-19 pandemic has led to the scaling up of CP therapy to unprecedented levels. Compared with historical usage, pathogen reduction technologies have now added an extra layer of safety to the use of CP, and new manufacturing approaches are being explored. This review summarizes historical settings of application, with a focus on betacoronaviruses, and surveys current approaches for donor selection and CP collection, pooling technologies, pathogen inactivation systems, and banking of CP. We additionally list the ongoing registered clinical trials for CP throughout the world and discuss the trial results published thus far.


Subject(s)
Coronavirus Infections/therapy , Pneumonia, Viral/therapy , Antibodies, Neutralizing/analysis , Biological Specimen Banks/standards , Donor Selection/methods , Donor Selection/standards , Enzyme-Linked Immunosorbent Assay , Humans , Immunization, Passive/adverse effects , Immunization, Passive/standards , Neutralization Tests/standards , Pandemics , Severe Acute Respiratory Syndrome/therapy
4.
J Exp Med ; 217(11)2020 11 02.
Article in English | MEDLINE | ID: covidwho-697830

ABSTRACT

The emergence of SARS-CoV-2 and the ensuing explosive epidemic of COVID-19 disease has generated a need for assays to rapidly and conveniently measure the antiviral activity of SARS-CoV-2-specific antibodies. Here, we describe a collection of approaches based on SARS-CoV-2 spike-pseudotyped, single-cycle, replication-defective human immunodeficiency virus type-1 (HIV-1), and vesicular stomatitis virus (VSV), as well as a replication-competent VSV/SARS-CoV-2 chimeric virus. While each surrogate virus exhibited subtle differences in the sensitivity with which neutralizing activity was detected, the neutralizing activity of both convalescent plasma and human monoclonal antibodies measured using each virus correlated quantitatively with neutralizing activity measured using an authentic SARS-CoV-2 neutralization assay. The assays described herein are adaptable to high throughput and are useful tools in the evaluation of serologic immunity conferred by vaccination or prior SARS-CoV-2 infection, as well as the potency of convalescent plasma or human monoclonal antibodies.


Subject(s)
Antibodies, Neutralizing/analysis , Antibodies, Viral/analysis , Betacoronavirus/immunology , Coronavirus Infections/immunology , Immunoassay/methods , Pneumonia, Viral/immunology , Animals , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Betacoronavirus/genetics , Cell Line , Chimera/genetics , Chimera/immunology , Chlorocebus aethiops , Coronavirus Infections/virology , HEK293 Cells , HIV-1/genetics , HIV-1/immunology , Humans , Neutralization Tests/methods , Pandemics , Pneumonia, Viral/virology , Recombination, Genetic , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Vero Cells , Vesicular stomatitis Indiana virus/genetics , Vesicular stomatitis Indiana virus/immunology
6.
Nature ; 584(7821): 450-456, 2020 08.
Article in English | MEDLINE | ID: covidwho-664494

ABSTRACT

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic continues, with devasting consequences for human lives and the global economy1,2. The discovery and development of virus-neutralizing monoclonal antibodies could be one approach to treat or prevent infection by this coronavirus. Here we report the isolation of sixty-one SARS-CoV-2-neutralizing monoclonal antibodies from five patients infected with SARS-CoV-2 and admitted to hospital with severe coronavirus disease 2019 (COVID-19). Among these are nineteen antibodies that potently neutralized authentic SARS-CoV-2 in vitro, nine of which exhibited very high potency, with 50% virus-inhibitory concentrations of 0.7 to 9 ng ml-1. Epitope mapping showed that this collection of nineteen antibodies was about equally divided between those directed against the receptor-binding domain (RBD) and those directed against the N-terminal domain (NTD), indicating that both of these regions at the top of the viral spike are immunogenic. In addition, two other powerful neutralizing antibodies recognized quaternary epitopes that overlap with the domains at the top of the spike. Cryo-electron microscopy reconstructions of one antibody that targets the RBD, a second that targets the NTD, and a third that bridges two separate RBDs showed that the antibodies recognize the closed, 'all RBD-down' conformation of the spike. Several of these monoclonal antibodies are promising candidates for clinical development as potential therapeutic and/or prophylactic agents against SARS-CoV-2.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Betacoronavirus/immunology , Coronavirus Infections/immunology , Epitopes, B-Lymphocyte/immunology , Pneumonia, Viral/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Monoclonal/analysis , Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/ultrastructure , Antibodies, Neutralizing/analysis , Antibodies, Neutralizing/chemistry , Antibodies, Neutralizing/ultrastructure , Antibodies, Viral/analysis , Antibodies, Viral/chemistry , Antibodies, Viral/ultrastructure , Betacoronavirus/chemistry , Betacoronavirus/ultrastructure , Coronavirus Infections/prevention & control , Cryoelectron Microscopy , Disease Models, Animal , Epitope Mapping , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/ultrastructure , Female , Humans , Immunoglobulin Fab Fragments/chemistry , Immunoglobulin Fab Fragments/immunology , Immunoglobulin Fab Fragments/ultrastructure , Lung/pathology , Lung/virology , Male , Mesocricetus , Models, Molecular , Neutralization Tests , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Spike Glycoprotein, Coronavirus/ultrastructure
7.
Nature ; 584(7821): 443-449, 2020 08.
Article in English | MEDLINE | ID: covidwho-647154

ABSTRACT

The ongoing pandemic of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a major threat to global health1 and the medical countermeasures available so far are limited2,3. Moreover, we currently lack a thorough understanding of the mechanisms of humoral immunity to SARS-CoV-24. Here we analyse a large panel of human monoclonal antibodies that target the spike (S) glycoprotein5, and identify several that exhibit potent neutralizing activity and fully block the receptor-binding domain of the S protein (SRBD) from interacting with human angiotensin-converting enzyme 2 (ACE2). Using competition-binding, structural and functional studies, we show that the monoclonal antibodies can be clustered into classes that recognize distinct epitopes on the SRBD, as well as distinct conformational states of the S trimer. Two potently neutralizing monoclonal antibodies, COV2-2196 and COV2-2130, which recognize non-overlapping sites, bound simultaneously to the S protein and neutralized wild-type SARS-CoV-2 virus in a synergistic manner. In two mouse models of SARS-CoV-2 infection, passive transfer of COV2-2196, COV2-2130 or a combination of both of these antibodies protected mice from weight loss and reduced the viral burden and levels of inflammation in the lungs. In addition, passive transfer of either of two of the most potent ACE2-blocking monoclonal antibodies (COV2-2196 or COV2-2381) as monotherapy protected rhesus macaques from SARS-CoV-2 infection. These results identify protective epitopes on the SRBD and provide a structure-based framework for rational vaccine design and the selection of robust immunotherapeutic agents.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Betacoronavirus/immunology , Coronavirus Infections/immunology , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/immunology , Pneumonia, Viral/prevention & control , Animals , Antibodies, Monoclonal/immunology , Betacoronavirus/chemistry , Binding, Competitive , Cell Line , Cross Reactions , Disease Models, Animal , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/immunology , Female , Humans , Macaca mulatta , Male , Mice , Middle Aged , Neutralization Tests , Peptidyl-Dipeptidase A/genetics , Peptidyl-Dipeptidase A/metabolism , Pre-Exposure Prophylaxis , SARS Virus/chemistry , SARS Virus/immunology , Severe Acute Respiratory Syndrome/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism
8.
J Clin Virol ; 129: 104539, 2020 08.
Article in English | MEDLINE | ID: covidwho-633896

ABSTRACT

BACKGROUND: Serological tests for anti-SARS-CoV-2 antibodies are becoming of great interest to determine seroprevalence in a given population, define previous exposure and identify highly reactive human donors for the generation of convalescent serum as therapeutic. OBJECTIVES: We evaluated the diagnostic performance of the Abbott ARCHITECT SARS-CoV-2 IgG test, a fully automated indirect immunoassay that detects antibodies directed to a recombinant SARS-CoV-2 Nucleocapsid antigen. STUDY DESIGN: Abbott ARCHITECT SARS-CoV-2 IgG immunoassay was compared to an indirect immunofluorescence assay (IFA) on sera from patients with COVID-19 collected at different days after symptoms onset or infected by other human coronaviruses. Comparison with neutralization test was also performed. RESULTS: After 7, 14 and >14 days after onset ARCHITECT was positive on 8.3 %; 61.9 % and 100 % of the tested samples compared to 58.3 %; 85.7 % and 100 % by IFA. The sensitivity was 72 % vs. IFA and 66.7 % vs. a real-time PCR, the specificity was 100 %. On 18 samples with neutralizing activity, 17 were positive by Abbott ARCHITECT SARS-CoV-2 IgG. CONCLUSIONS: In our study, Abbott ARCHITECT SARS-CoV-2 IgG assay showed a satisfactory performance, with a very high specificity. IgG reactivity against SARSCoV-2 N antigen was detectable in all patients by two weeks after symptoms onset. In addition, concordance between this serological response and viral neutralization suggests that a strong humoral response may be predictive of a neutralization activity, regardless of the target antigens. This finding supports the use of this automated serological assay in diagnostic algorithm and public health intervention, especially for high loads of testing.


Subject(s)
Antibodies, Viral/blood , Betacoronavirus/immunology , Clinical Laboratory Techniques/methods , Coronavirus Infections/diagnosis , Fluorescent Antibody Technique, Indirect/methods , Neutralization Tests/methods , Pneumonia, Viral/diagnosis , Serologic Tests/methods , Adolescent , Adult , Aged , Aged, 80 and over , Antibodies, Neutralizing/blood , Child , Child, Preschool , Female , Humans , Immunoglobulin G/blood , Infant , Infant, Newborn , Male , Middle Aged , Pandemics , Sensitivity and Specificity , Young Adult
9.
Nat Commun ; 11(1): 3436, 2020 07 06.
Article in English | MEDLINE | ID: covidwho-630511

ABSTRACT

The world is entering a new era of the COVID-19 pandemic in which there is an increasing call for reliable antibody testing. To support decision making on the deployment of serology for either population screening or diagnostics, we present a detailed comparison of serological COVID-19 assays. We show that among the selected assays there is a wide diversity in assay performance in different scenarios and when correlated to virus neutralizing antibodies. The Wantai ELISA detecting total immunoglobulins against the receptor binding domain of SARS CoV-2, has the best overall characteristics to detect functional antibodies in different stages and severity of disease, including the potential to set a cut-off indicating the presence of protective antibodies. The large variety of available serological assays requires proper assay validation before deciding on deployment of assays for specific applications.


Subject(s)
Antibodies, Viral/blood , Coronavirus Infections/diagnosis , Pneumonia, Viral/diagnosis , Serologic Tests/standards , Antibodies, Neutralizing/blood , Betacoronavirus , Clinical Laboratory Techniques , Enzyme-Linked Immunosorbent Assay , High-Throughput Screening Assays , Humans , Luminescent Measurements , Neutralization Tests , Pandemics , Sensitivity and Specificity
10.
J Infect ; 81(3): e31-e32, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-625901

ABSTRACT

We followed-up a mild COVID-19 patient for 91 days and serially monitored his serum antibodies to four SARS-CoV-2 related antigens (NP, RBD, S1 and ECD) and neutralization activities. Our data revealed a profile of serial antibody responses during the progress and a quick decline of neutralization activities after discharge.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Betacoronavirus/immunology , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , Adult , Antigens, Viral/immunology , Enzyme-Linked Immunosorbent Assay , Humans , Longitudinal Studies , Male , Neutralization Tests , Pandemics , RNA, Viral , Retrospective Studies
11.
Cell Rep ; 32(3): 107918, 2020 07 21.
Article in English | MEDLINE | ID: covidwho-625076

ABSTRACT

Coronavirus disease 2019 (COVID-19) has become a worldwide threat to humans, and neutralizing antibodies have therapeutic potential. We have purified more than 1,000 memory B cells specific to SARS-CoV-2 S1 or its RBD (receptor binding domain) and obtain 729 paired heavy- and light-chain fragments. Among these, 178 antibodies test positive for antigen binding, and the majority of the top 17 binders with EC50 below 1 nM are RBD binders. Furthermore, we identify 11 neutralizing antibodies, eight of which show IC50 within 10 nM, and the best one, 414-1, with IC50 of 1.75 nM. Through epitope mapping, we find three main epitopes in RBD recognized by these antibodies, and epitope-B antibody 553-15 could substantially enhance the neutralizing abilities of most of the other antibodies. We also find that 515-5 could cross neutralize the SARS-CoV pseudovirus. Altogether, our study provides 11 potent human neutralizing antibodies for COVID-19 as therapeutic candidates.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Betacoronavirus/immunology , Receptors, Virus/immunology , Spike Glycoprotein, Coronavirus/immunology , Antibodies, Monoclonal/therapeutic use , B-Lymphocytes/immunology , Coronavirus Infections/therapy , Epitope Mapping , Epitopes/immunology , Humans , Immunologic Memory/immunology , Neutralization Tests , Pandemics , Pneumonia, Viral/therapy , Protein Domains/immunology
12.
Curr Protoc Microbiol ; 58(1): e108, 2020 09.
Article in English | MEDLINE | ID: covidwho-614201

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in the city of Wuhan, Hubei Province, China, in late 2019. Since then, the virus has spread globally and caused a pandemic. Assays that can measure the antiviral activity of antibodies or antiviral compounds are needed for SARS-CoV-2 vaccine and drug development. Here, we describe in detail a microneutralization assay, which can be used to assess in a quantitative manner if antibodies or drugs can block entry and/or replication of SARS-CoV-2 in vitro. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Microneutralization assay to test inhibition of virus by antibodies (purified antibodies or serum/plasma) Basic Protocol 2: Screening of anti-SARS-CoV-2 compounds in vitro Support Protocol: SARS-CoV-2 propagation.


Subject(s)
Antibodies, Viral/immunology , Betacoronavirus/immunology , Drug Evaluation, Preclinical/methods , Neutralization Tests/methods , Animals , Chlorocebus aethiops , Coronavirus Infections/immunology , Coronavirus Infections/virology , Humans , Mice , Pandemics , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , Vero Cells , Virus Internalization/drug effects , Virus Replication/drug effects
13.
Nature ; 584(7821): 437-442, 2020 08.
Article in English | MEDLINE | ID: covidwho-606946

ABSTRACT

During the coronavirus disease-2019 (COVID-19) pandemic, severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) has led to the infection of millions of people and has claimed hundreds of thousands of lives. The entry of the virus into cells depends on the receptor-binding domain (RBD) of the spike (S) protein of SARS-CoV-2. Although there is currently no vaccine, it is likely that antibodies will be essential for protection. However, little is known about the human antibody response to SARS-CoV-21-5. Here we report on 149 COVID-19-convalescent individuals. Plasma samples collected an average of 39 days after the onset of symptoms had variable half-maximal pseudovirus neutralizing titres; titres were less than 50 in 33% of samples, below 1,000 in 79% of samples and only 1% of samples had titres above 5,000. Antibody sequencing revealed the expansion of clones of RBD-specific memory B cells that expressed closely related antibodies in different individuals. Despite low plasma titres, antibodies to three distinct epitopes on the RBD neutralized the virus with half-maximal inhibitory concentrations (IC50 values) as low as 2 ng ml-1. In conclusion, most convalescent plasma samples obtained from individuals who recover from COVID-19 do not contain high levels of neutralizing activity. Nevertheless, rare but recurring RBD-specific antibodies with potent antiviral activity were found in all individuals tested, suggesting that a vaccine designed to elicit such antibodies could be broadly effective.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Betacoronavirus/immunology , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , Adolescent , Adult , Aged , Antibodies, Monoclonal/analysis , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/analysis , Antibodies, Viral/analysis , Antibody Specificity , Coronavirus Infections/prevention & control , Enzyme-Linked Immunosorbent Assay , Female , Humans , Male , Middle Aged , Neutralization Tests , Pandemics , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Viral Vaccines/immunology , Young Adult
14.
Euro Surveill ; 25(24)2020 06.
Article in English | MEDLINE | ID: covidwho-605371

ABSTRACT

We evaluated SARS-CoV-2 RNA and neutralising antibodies in blood donors (BD) residing in the Lodi Red Zone, Italy. Of 390 BDs recruited after 20 February 2020 - when the first COVID-19 case in Lombardy was identified, 91 (23%) aged 19-70 years were antibody positive. Viral RNA was detected in an additional 17 (4.3%) BDs, yielding ca 28% (108/390) with evidence of virus exposure. Five stored samples collected as early as 12 February were seropositive.


Subject(s)
Antibodies, Neutralizing/immunology , Betacoronavirus/immunology , Coronavirus Infections/epidemiology , Pneumonia, Viral/epidemiology , Adult , Aged , Blood Donors , Clinical Laboratory Techniques , Coronavirus Infections/diagnosis , Coronavirus Infections/immunology , Coronavirus Infections/therapy , Female , Humans , Immunization, Passive , Italy/epidemiology , Male , Middle Aged , Neutralization Tests , Pandemics , Pneumonia, Viral/immunology , Pneumonia, Viral/therapy , Prevalence , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Seroepidemiologic Studies , Young Adult
15.
Viruses ; 12(6)2020 06 13.
Article in English | MEDLINE | ID: covidwho-602214

ABSTRACT

As of June 2020, the number of people infected with severe acute respiratory coronavirus 2 (SARS-CoV-2) continues to skyrocket, with more than 6.7 million cases worldwide. Both the World Health Organization (WHO) and United Nations (UN) has highlighted the need for better control of SARS-CoV-2 infections. However, developing novel virus-specific vaccines, monoclonal antibodies and antiviral drugs against SARS-CoV-2 can be time-consuming and costly. Convalescent sera and safe-in-man broad-spectrum antivirals (BSAAs) are readily available treatment options. Here, we developed a neutralization assay using SARS-CoV-2 strain and Vero-E6 cells. We identified the most potent sera from recovered patients for the treatment of SARS-CoV-2-infected patients. We also screened 136 safe-in-man broad-spectrum antivirals against the SARS-CoV-2 infection in Vero-E6 cells and identified nelfinavir, salinomycin, amodiaquine, obatoclax, emetine and homoharringtonine. We found that a combination of orally available virus-directed nelfinavir and host-directed amodiaquine exhibited the highest synergy. Finally, we developed a website to disseminate the knowledge on available and emerging treatments of COVID-19.


Subject(s)
Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Coronavirus Infections/drug therapy , Neutralization Tests/methods , Pneumonia, Viral/drug therapy , Amodiaquine/pharmacology , Animals , Caco-2 Cells , Cell Line, Tumor , Chlorocebus aethiops , Coronavirus Infections/therapy , Drug Therapy, Combination , Emetine/pharmacology , HEK293 Cells , HT29 Cells , Homoharringtonine/pharmacology , Humans , Immune Sera/immunology , Immunization, Passive/methods , Nelfinavir/pharmacology , Pandemics , Pyrans/pharmacology , Pyrroles/pharmacology , Vero Cells
16.
Science ; 369(6506): 1014-1018, 2020 08 21.
Article in English | MEDLINE | ID: covidwho-599039

ABSTRACT

Antibodies targeting the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) present a promising approach to combat the coronavirus disease 2019 (COVID-19) pandemic; however, concerns remain that mutations can yield antibody resistance. We investigated the development of resistance against four antibodies to the spike protein that potently neutralize SARS-CoV-2, individually as well as when combined into cocktails. These antibodies remain effective against spike variants that have arisen in the human population. However, novel spike mutants rapidly appeared after in vitro passaging in the presence of individual antibodies, resulting in loss of neutralization; such escape also occurred with combinations of antibodies binding diverse but overlapping regions of the spike protein. Escape mutants were not generated after treatment with a noncompeting antibody cocktail.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Betacoronavirus/immunology , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , Spike Glycoprotein, Coronavirus/immunology , Betacoronavirus/chemistry , Betacoronavirus/genetics , Epitopes , Genome, Viral , Humans , Mutant Proteins/chemistry , Mutant Proteins/immunology , Mutation , Neutralization Tests , Pandemics , Protein Interaction Domains and Motifs , Selection, Genetic , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics
17.
Science ; 369(6506): 1010-1014, 2020 08 21.
Article in English | MEDLINE | ID: covidwho-599036

ABSTRACT

Neutralizing antibodies have become an important tool in treating infectious diseases. Recently, two separate approaches yielded successful antibody treatments for Ebola-one from genetically humanized mice and the other from a human survivor. Here, we describe parallel efforts using both humanized mice and convalescent patients to generate antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein, which yielded a large collection of fully human antibodies that were characterized for binding, neutralization, and three-dimensional structure. On the basis of these criteria, we selected pairs of highly potent individual antibodies that simultaneously bind the receptor binding domain of the spike protein, thereby providing ideal partners for a therapeutic antibody cocktail that aims to decrease the potential for virus escape mutants that might arise in response to selective pressure from a single-antibody treatment.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Betacoronavirus/immunology , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , Spike Glycoprotein, Coronavirus/immunology , Adolescent , Adult , Animals , Antibodies, Neutralizing/chemistry , Antibodies, Viral/chemistry , Antibody Affinity , Antibody-Dependent Cell Cytotoxicity , Betacoronavirus/chemistry , Binding Sites, Antibody , Broadly Neutralizing Antibodies/chemistry , Broadly Neutralizing Antibodies/immunology , Cell Line , Coronavirus Infections/therapy , Cytophagocytosis , Epitopes , Humans , Immunization, Passive , Mice , Middle Aged , Models, Molecular , Neutralization Tests , Pandemics , Peptidyl-Dipeptidase A/metabolism , Protein Interaction Domains and Motifs , Receptors, Virus/metabolism , SARS Virus/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Young Adult
18.
Science ; 369(6506): 956-963, 2020 08 21.
Article in English | MEDLINE | ID: covidwho-599034

ABSTRACT

Countermeasures to prevent and treat coronavirus disease 2019 (COVID-19) are a global health priority. We enrolled a cohort of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-recovered participants, developed neutralization assays to investigate antibody responses, adapted our high-throughput antibody generation pipeline to rapidly screen more than 1800 antibodies, and established an animal model to test protection. We isolated potent neutralizing antibodies (nAbs) to two epitopes on the receptor binding domain (RBD) and to distinct non-RBD epitopes on the spike (S) protein. As indicated by maintained weight and low lung viral titers in treated animals, the passive transfer of a nAb provides protection against disease in high-dose SARS-CoV-2 challenge in Syrian hamsters. The study suggests a role for nAbs in prophylaxis, and potentially therapy, of COVID-19. The nAbs also define protective epitopes to guide vaccine design.


Subject(s)
Antibodies, Monoclonal , Antibodies, Neutralizing , Antibodies, Viral , Betacoronavirus/immunology , Coronavirus Infections/immunology , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/immunology , Pneumonia, Viral/prevention & control , Adult , Animals , Antibodies, Monoclonal/blood , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/isolation & purification , Antibodies, Monoclonal/therapeutic use , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/isolation & purification , Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/blood , Antibodies, Viral/immunology , Antibodies, Viral/isolation & purification , Antibodies, Viral/therapeutic use , Antibody Affinity , Antibody Specificity , Betacoronavirus/physiology , Binding Sites , Cell Line , Coronavirus Infections/therapy , Coronavirus Infections/virology , Disease Models, Animal , Epitopes , Female , Humans , Immunization, Passive , Lung/virology , Male , Mesocricetus , Middle Aged , Neutralization Tests , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/therapy , Pneumonia, Viral/virology , Protein Domains , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism , Viral Load , Virus Replication
19.
Science ; 369(6504): 731-736, 2020 08 07.
Article in English | MEDLINE | ID: covidwho-599033

ABSTRACT

Broadly protective vaccines against known and preemergent human coronaviruses (HCoVs) are urgently needed. To gain a deeper understanding of cross-neutralizing antibody responses, we mined the memory B cell repertoire of a convalescent severe acute respiratory syndrome (SARS) donor and identified 200 SARS coronavirus 2 (SARS-CoV-2) binding antibodies that target multiple conserved sites on the spike (S) protein. A large proportion of the non-neutralizing antibodies display high levels of somatic hypermutation and cross-react with circulating HCoVs, suggesting recall of preexisting memory B cells elicited by prior HCoV infections. Several antibodies potently cross-neutralize SARS-CoV, SARS-CoV-2, and the bat SARS-like virus WIV1 by blocking receptor attachment and inducing S1 shedding. These antibodies represent promising candidates for therapeutic intervention and reveal a target for the rational design of pan-sarbecovirus vaccines.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Viral/immunology , Betacoronavirus/immunology , Broadly Neutralizing Antibodies/immunology , SARS Virus/immunology , Spike Glycoprotein, Coronavirus/immunology , Adult , Aged , Antibody Affinity , B-Lymphocyte Subsets/immunology , Binding Sites , Cross Reactions , Epitopes , Female , Humans , Immunologic Memory , Male , Middle Aged , Neutralization Tests , Peptidyl-Dipeptidase A/chemistry , Peptidyl-Dipeptidase A/metabolism , Protein Domains , Receptors, Virus/chemistry , Receptors, Virus/metabolism , Severe Acute Respiratory Syndrome/immunology , Somatic Hypermutation, Immunoglobulin , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Young Adult
20.
J Clin Virol ; 129: 104512, 2020 08.
Article in English | MEDLINE | ID: covidwho-598659

ABSTRACT

There is an urgent need for reliable high-throughput serological assays for the management of the ongoing COVID-19 pandemic. Preferably, the performance of serological tests for a novel virus should be determined with clinical specimens against a gold standard, i.e. virus neutralisation. We compared the performance of six commercial immunoassays for the detection of SARS-COV-2 IgG, IgA and IgM antibodies, including four automated assays [Abbott SARS-COV-2 IgG (CE marked), Diasorin Liaison® SARS-COV-2 S1/S2 IgG (research use only, RUO), and Euroimmun SARS-COV-2 IgG and IgA (CE marked)], and two rapid lateral flow (immunocromatographic) tests [Acro Biotech 2019-nCoV IgG/IgM (CE marked) and Xiamen Biotime Biotechnology SARS-COV-2 IgG/IgM (CE marked)] with a microneutralisation test (MNT). Two specimen panels from serum samples sent to Helsinki University Hospital Laboratory (HUSLAB) were compiled: the patient panel (N=70) included sera from PCR confirmed COVID-19 patients, and the negative panel (N=81) included sera sent for screening of autoimmune diseases and respiratory virus antibodies in 2018 and 2019. The MNT was carried out for all COVID-19 samples (70 serum samples, 62 individuals) and for 53 samples from the negative panel. Forty-one out of 62 COVID-19 patients showed neutralising antibodies.The specificity and sensitivity values of the commercial tests against MNT, respectively, were as follows: 95.1 %/80.5 % (Abbott Architect SARS-CoV-2 IgG), 94.9 %/43.8 % (Diasorin Liaison SARS-CoV-2 IgG; RUO), 68.3 %/87.8 % (Euroimmun SARS-CoV-2 IgA), 86.6 %/70.7 % (Euroimmun SARS-CoV-2 IgG), 74.4 %/56.1 % (Acro 2019-nCoV IgG), 69.5 %/46.3 % (Acro 2019-nCoV IgM), 97.5 %/71.9 % (Xiamen Biotime SARS-CoV-2 IgG), and 88.8 %/81.3 % (Xiamen Biotime SARS-CoV-2 IgM). This study shows variable performance values. Laboratories should carefully consider their testing process, such as a two-tier approach, in order to optimize the overall performance of SARS- CoV-2 serodiagnostics.


Subject(s)
Antibodies, Viral/blood , Betacoronavirus/immunology , Clinical Laboratory Techniques/methods , Coronavirus Infections/diagnosis , Neutralization Tests/methods , Pneumonia, Viral/diagnosis , Serologic Tests/methods , Adolescent , Adult , Aged , Aged, 80 and over , Automation, Laboratory/methods , Child , Child, Preschool , Female , Hospitals , Humans , Immunoassay/methods , Immunoglobulin A/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , Pandemics , Sensitivity and Specificity , Young Adult
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