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1.
Euro Surveill ; 25(28)2020 07.
Article in English | MEDLINE | ID: covidwho-647504

ABSTRACT

BackgroundA novel coronavirus, SARS-CoV-2, which emerged at the end of 2019 and causes COVID-19, has resulted in worldwide human infections. While genetically distinct, SARS-CoV-1, the aetiological agent responsible for an outbreak of severe acute respiratory syndrome (SARS) in 2002-2003, utilises the same host cell receptor as SARS-CoV-2 for entry: angiotensin-converting enzyme 2 (ACE2). Parts of the SARS-CoV-1 spike glycoprotein (S protein), which interacts with ACE2, appear conserved in SARS-CoV-2.AimThe cross-reactivity with SARS-CoV-2 of monoclonal antibodies (mAbs) previously generated against the S protein of SARS-CoV-1 was assessed.MethodsThe SARS-CoV-2 S protein sequence was aligned to those of SARS-CoV-1, Middle East respiratory syndrome (MERS) and common-cold coronaviruses. Abilities of mAbs generated against SARS-CoV-1 S protein to bind SARS-CoV-2 or its S protein were tested with SARS-CoV-2 infected cells as well as cells expressing either the full length protein or a fragment of its S2 subunit. Quantitative ELISA was also performed to compare binding of mAbs to recombinant S protein.ResultsAn immunogenic domain in the S2 subunit of SARS-CoV-1 S protein is highly conserved in SARS-CoV-2 but not in MERS and human common-cold coronaviruses. Four murine mAbs raised against this immunogenic fragment could recognise SARS-CoV-2 S protein expressed in mammalian cell lines. In particular, mAb 1A9 was demonstrated to detect S protein in SARS-CoV-2-infected cells and is suitable for use in a sandwich ELISA format.ConclusionThe cross-reactive mAbs may serve as useful tools for SARS-CoV-2 research and for the development of diagnostic assays for COVID-19.


Subject(s)
Antibodies, Monoclonal/immunology , Betacoronavirus/immunology , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , SARS Virus/immunology , Severe Acute Respiratory Syndrome/immunology , Spike Glycoprotein, Coronavirus/immunology , Amino Acid Sequence , Animals , Betacoronavirus/genetics , Blotting, Western , COS Cells , Chlorocebus aethiops , Conserved Sequence , Coronavirus Infections/genetics , Coronavirus Infections/virology , Cross Reactions/immunology , Enzyme-Linked Immunosorbent Assay/methods , Fluorescent Antibody Technique/methods , Genome, Viral , Mice , Pandemics , Peptidyl-Dipeptidase A/immunology , Plasmids , Pneumonia, Viral/genetics , Recombinant Proteins/immunology , SARS Virus/genetics , Sequence Alignment , Severe Acute Respiratory Syndrome/virology , Spike Glycoprotein, Coronavirus/genetics , Transfection , Vero Cells , Virus Integration
2.
Euro Surveill ; 25(28)2020 07.
Article in English | MEDLINE | ID: covidwho-647501

ABSTRACT

Most cases of coronavirus disease 2019 are mild or asymptomatic. Therefore, many cases remain unrecorded. We determined seroprevalence of IgG antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 3,186 regular blood donors in three German federal states between 9 March and 3 June 2020. The IgG seroprevalence was 0.91% (95% confidence interval (CI): 0.58-1.24) overall, ranging from 0.66% (95% CI: 0.13-1.19) in Hesse to 1.22% (95% CI: 0.33-2.10) in Lower-Saxony.


Subject(s)
Betacoronavirus/immunology , Blood Donors/statistics & numerical data , Coronavirus Infections/immunology , Immunoglobulin G/blood , Pneumonia, Viral/immunology , Coronavirus Infections/blood , Coronavirus Infections/diagnosis , Coronavirus Infections/epidemiology , Enzyme-Linked Immunosorbent Assay , Female , Germany/epidemiology , Humans , Male , Pandemics , Pneumonia, Viral/blood , Pneumonia, Viral/diagnosis , Pneumonia, Viral/epidemiology , Seroepidemiologic Studies , Spike Glycoprotein, Coronavirus/immunology , Time Factors
3.
J Virol ; 94(17)2020 08 17.
Article in English | MEDLINE | ID: covidwho-748774

ABSTRACT

In this review, we address issues that relate to the rapid "Warp Speed" development of vaccines to counter the COVID-19 pandemic. We review the antibody response that is triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection of humans and how it may inform vaccine research. The isolation and properties of neutralizing monoclonal antibodies from COVID-19 patients provide additional information on what vaccines should try to elicit. The nature and longevity of the antibody response to coronaviruses are relevant to the potency and duration of vaccine-induced immunity. We summarize the immunogenicity of leading vaccine candidates tested to date in animals and humans and discuss the outcome and interpretation of virus challenge experiments in animals. By far the most immunogenic vaccine candidates for antibody responses are recombinant proteins, which were not included in the initial wave of Warp Speed immunogens. A substantial concern for SARS-CoV-2 vaccines is adverse events, which we review by considering what was seen in studies of SARS-CoV-1 and Middle East respiratory syndrome coronavirus (MERS-CoV) vaccines. We conclude by outlining the possible outcomes of the Warp Speed vaccine program, which range from the hoped-for rapid success to a catastrophic adverse influence on vaccine uptake generally.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/prevention & control , Immunogenicity, Vaccine/immunology , Pneumonia, Viral/prevention & control , Viral Vaccines/immunology , Animals , Antibodies, Neutralizing , Antibodies, Viral/immunology , Humans , Middle East Respiratory Syndrome Coronavirus/immunology , Models, Animal , Pandemics/prevention & control , Spike Glycoprotein, Coronavirus/immunology , Viral Vaccines/adverse effects
4.
Nat Commun ; 11(1): 4303, 2020 08 27.
Article in English | MEDLINE | ID: covidwho-733523

ABSTRACT

The novel highly transmissible human coronavirus SARS-CoV-2 is the causative agent of the COVID-19 pandemic. Thus far, there is no approved therapeutic drug specifically targeting this emerging virus. Here we report the isolation and characterization of a panel of human neutralizing monoclonal antibodies targeting the SARS-CoV-2 receptor binding domain (RBD). These antibodies were selected from a phage display library constructed using peripheral circulatory lymphocytes collected from patients at the acute phase of the disease. These neutralizing antibodies are shown to recognize distinct epitopes on the viral spike RBD. A subset of the antibodies exert their inhibitory activity by abrogating binding of the RBD to the human ACE2 receptor. The human monoclonal antibodies described here represent a promising basis for the design of efficient combined post-exposure therapy for SARS-CoV-2 infection.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Betacoronavirus/immunology , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Monoclonal/metabolism , Antibodies, Neutralizing/metabolism , Antibodies, Viral/immunology , Antibodies, Viral/metabolism , Betacoronavirus/metabolism , Chlorocebus aethiops , Epitope Mapping , Epitopes , Humans , Peptide Library , Peptidyl-Dipeptidase A/metabolism , Protein Binding , Protein Interaction Domains and Motifs , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells
5.
PLoS Pathog ; 16(8): e1008762, 2020 08.
Article in English | MEDLINE | ID: covidwho-727333

ABSTRACT

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is a newly emerging, highly transmissible, and pathogenic coronavirus in humans that has caused global public health emergencies and economic crises. To date, millions of infections and thousands of deaths have been reported worldwide, and the numbers continue to rise. Currently, there is no specific drug or vaccine against this deadly virus; therefore, there is a pressing need to understand the mechanism(s) through which this virus enters the host cell. Viral entry into the host cell is a multistep process in which SARS-CoV-2 utilizes the receptor-binding domain (RBD) of the spike (S) glycoprotein to recognize angiotensin-converting enzyme 2 (ACE2) receptors on the human cells; this initiates host-cell entry by promoting viral-host cell membrane fusion through large-scale conformational changes in the S protein. Receptor recognition and fusion are critical and essential steps of viral infections and are key determinants of the viral host range and cross-species transmission. In this review, we summarize the current knowledge on the origin and evolution of SARS-CoV-2 and the roles of key viral factors. We discuss the structure of RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 and its significance in drug discovery and explain the receptor recognition mechanisms of coronaviruses. Further, we provide a comparative analysis of the SARS-CoV and SARS-CoV-2 S proteins and their receptor-binding specificity and discuss the differences in their antigenicity based on biophysical and structural characteristics.


Subject(s)
Betacoronavirus/pathogenicity , Coronavirus Infections/virology , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/virology , Spike Glycoprotein, Coronavirus/metabolism , Animals , Coronavirus Infections/metabolism , Humans , Pandemics , Pneumonia, Viral/metabolism , Receptors, Virus/immunology , Receptors, Virus/metabolism , Spike Glycoprotein, Coronavirus/immunology , Virus Internalization
6.
Nat Commun ; 11(1): 4207, 2020 08 21.
Article in English | MEDLINE | ID: covidwho-724410

ABSTRACT

The rapid spread of coronavirus SARS-CoV-2 greatly threatens global public health but no prophylactic vaccine is available. Here, we report the generation of a replication-incompetent recombinant serotype 5 adenovirus, Ad5-S-nb2, carrying a codon-optimized gene encoding Spike protein (S). In mice and rhesus macaques, intramuscular injection with Ad5-S-nb2 elicits systemic S-specific antibody and cell-mediated immune (CMI) responses. Intranasal inoculation elicits both systemic and pulmonary antibody responses but weaker CMI response. At 30 days after a single vaccination with Ad5-S-nb2 either intramuscularly or intranasally, macaques are protected against SARS-CoV-2 challenge. A subsequent challenge reveals that macaques vaccinated with a 10-fold lower vaccine dosage (1 × 1010 viral particles) are also protected, demonstrating the effectiveness of Ad5-S-nb2 and the possibility of offering more vaccine dosages within a shorter timeframe. Thus, Ad5-S-nb2 is a promising candidate vaccine and warrants further clinical evaluation.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Viral Vaccines/administration & dosage , Adenoviridae/genetics , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Coronavirus Infections/immunology , Dose-Response Relationship, Immunologic , Female , HEK293 Cells , Humans , Immunity, Cellular , Macaca mulatta , Male , Mice , Mice, Inbred BALB C , Pneumonia, Viral/immunology , Respiratory System/pathology , Respiratory System/virology , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Vaccines, Synthetic/administration & dosage
7.
Nat Commun ; 11(1): 4198, 2020 08 21.
Article in English | MEDLINE | ID: covidwho-724360

ABSTRACT

COVID-19 caused by SARS-CoV-2 has become a global pandemic requiring the development of interventions for the prevention or treatment to curtail mortality and morbidity. No vaccine to boost mucosal immunity, or as a therapeutic, has yet been developed to SARS-CoV-2. In this study, we discover and characterize a cross-reactive human IgA monoclonal antibody, MAb362. MAb362 binds to both SARS-CoV and SARS-CoV-2 spike proteins and competitively blocks ACE2 receptor binding, by overlapping the ACE2 structural binding epitope. Furthermore, MAb362 IgA neutralizes both pseudotyped SARS-CoV and SARS-CoV-2 in 293 cells expressing ACE2. When converted to secretory IgA, MAb326 also neutralizes authentic SARS-CoV-2 virus while the IgG isotype shows no neutralization. Our results suggest that SARS-CoV-2 specific IgA antibodies, such as MAb362, may provide effective immunity against SARS-CoV-2 by inducing mucosal immunity within the respiratory system, a potentially critical feature of an effective vaccine.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Betacoronavirus/immunology , Immunoglobulin A/immunology , Peptidyl-Dipeptidase A/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Animals , Antibodies, Monoclonal/metabolism , Antibodies, Neutralizing/metabolism , Chlorocebus aethiops , Cross Reactions , Epitopes , HEK293 Cells , Humans , Immunoglobulin A/metabolism , Immunoglobulin A, Secretory/immunology , Immunoglobulin A, Secretory/metabolism , Immunoglobulin G/immunology , Immunoglobulin G/metabolism , Models, Molecular , Mutation , Protein Binding , Protein Interaction Domains and Motifs , SARS Virus/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Vero Cells
8.
PLoS One ; 15(8): e0237833, 2020.
Article in English | MEDLINE | ID: covidwho-717610

ABSTRACT

OBJECTIVE: Serological testing is needed to investigate the extent of transmission of SARS-CoV-2 from front-line essential workers to their household members. However, the requirement for serum/plasma limits serological testing to clinical settings where it is feasible to collect and process venous blood. To address this problem we developed a serological test for SARS-CoV-2 IgG antibodies that requires only a single drop of finger stick capillary whole blood, collected in the home and dried on filter paper (dried blood spot, DBS). We describe assay performance and demonstrate its utility for remote sampling with results from a community-based study. METHODS: An ELISA to the receptor binding domain of the SARS-CoV-2 spike protein was optimized to quantify IgG antibodies in DBS. Samples were self-collected from a community sample of 232 participants enriched with health care workers, including 30 known COVID-19 cases and their household members. RESULTS: Among 30 individuals sharing a household with a virus-confirmed case of COVID-19, 80% were seropositive. Of 202 community individuals without prior confirmed acute COVID-19 diagnoses, 36% were seropositive. Of documented convalescent COVID-19 cases from the community, 29 of 30 (97%) were seropositive for IgG antibodies to the receptor binding domain. CONCLUSION: DBS ELISA provides a minimally-invasive alternative to venous blood collection. Early analysis suggests a high rate of transmission among household members. High rates of seroconversion were also noted following recovery from infection. Serological testing for SARS-CoV-2 IgG antibodies in DBS samples can facilitate seroprevalence assessment in community settings to address epidemiological questions, monitor duration of antibody responses, and assess if antibodies against the spike protein correlate with protection from reinfection.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/diagnosis , Coronavirus Infections/epidemiology , Dried Blood Spot Testing , Family Characteristics , Health Personnel , Pneumonia, Viral/diagnosis , Pneumonia, Viral/epidemiology , Serologic Tests/methods , Adolescent , Adult , Aged , Antibodies, Viral/blood , Coronavirus Infections/transmission , Coronavirus Infections/virology , Enzyme-Linked Immunosorbent Assay , Female , Humans , Immunoglobulin G/blood , Male , Middle Aged , Pandemics , Pneumonia, Viral/transmission , Pneumonia, Viral/virology , Seroepidemiologic Studies , Spike Glycoprotein, Coronavirus/immunology , Young Adult
9.
Nat Commun ; 11(1): 4081, 2020 08 14.
Article in English | MEDLINE | ID: covidwho-717117

ABSTRACT

The unprecedented coronavirus disease 2019 (COVID-19) epidemic has created a worldwide public health emergency, and there is an urgent need to develop an effective vaccine to control this severe infectious disease. Here, we find that a single vaccination with a replication-defective human type 5 adenovirus encoding the SARS-CoV-2 spike protein (Ad5-nCoV) protect mice completely against mouse-adapted SARS-CoV-2 infection in the upper and lower respiratory tracts. Additionally, a single vaccination with Ad5-nCoV protects ferrets from wild-type SARS-CoV-2 infection in the upper respiratory tract. This study suggests that the mucosal vaccination may provide a desirable protective efficacy and this delivery mode is worth further investigation in human clinical trials.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Viral Vaccines/immunology , Animals , Antibodies, Viral/immunology , Coronavirus Infections/immunology , Disease Models, Animal , Drug Design , Female , Genetic Vectors , HEK293 Cells , Humans , Mice , Mice, Inbred BALB C , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Viral Vaccines/administration & dosage , Viral Vaccines/genetics
11.
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
12.
BMC Res Notes ; 13(1): 372, 2020 Aug 06.
Article in English | MEDLINE | ID: covidwho-696522

ABSTRACT

OBJECTIVE: COVID19 has caused a global and ongoing pandemic. The need for population seroconversion data is apparent to monitor and respond to the pandemic. Using a lateral flow assay (LFA) testing platform, the seropositivity in 63 New York Blood Center (NYBC) Convelescent Plasma (CP) donor samples were evaluated for the presence of COVID19 specific IgG and IgM. RESULTS: CP donors showed diverse antibody result. Convalescent donor plasma contains SARS-CoV-2 specific antibodies. Weak antibody bands may identify low titer CP donors. LFA tests can identify antibody positive individuals that have recovered from COVID19. Confirming suspected cases using antibody detection could help inform the patient and the community as to the relative risk to future exposure and a better understanding of disease exposure.


Subject(s)
Antibodies, Viral/blood , Antigens, Viral/immunology , Betacoronavirus/immunology , Blood Donors , Clinical Laboratory Techniques/methods , Convalescence , Coronavirus Infections/diagnosis , Immunoassay/methods , Immunoglobulin G/blood , Immunoglobulin M/blood , Nucleocapsid Proteins/immunology , Pandemics , Pneumonia, Viral/diagnosis , Point-of-Care Testing , Spike Glycoprotein, Coronavirus/immunology , Antibody Specificity , Coronavirus Infections/therapy , Gold Colloid , Humans , Immunization, Passive , Plasma , Protein Domains , Recombinant Proteins/immunology , Reproducibility of Results , Sensitivity and Specificity , Seroconversion
14.
Sci Immunol ; 5(49)2020 07 29.
Article in English | MEDLINE | ID: covidwho-690482

ABSTRACT

Limited data are available for pregnant women affected by SARS-CoV-2. Serological tests are critically important for determining SARS-CoV-2 exposures within both individuals and populations. We validated a SARS-CoV-2 spike receptor binding domain serological test using 834 pre-pandemic samples and 31 samples from COVID-19 recovered donors. We then completed SARS-CoV-2 serological testing of 1,293 parturient women at two centers in Philadelphia from April 4 to June 3, 2020. We found 80/1,293 (6.2%) of parturient women possessed IgG and/or IgM SARS-CoV-2-specific antibodies. We found race/ethnicity differences in seroprevalence rates, with higher rates in Black/non-Hispanic and Hispanic/Latino women. Of the 72 seropositive women who also received nasopharyngeal polymerase chain reaction testing during pregnancy, 46 (64%) were positive. Continued serologic surveillance among pregnant women may inform perinatal clinical practices and can potentially be used to estimate exposure to SARS-CoV-2 within the community.


Subject(s)
Antibodies, Viral/blood , Betacoronavirus/isolation & purification , Coronavirus Infections/epidemiology , Health Status Disparities , Pneumonia, Viral/epidemiology , Pregnancy Complications, Infectious/epidemiology , Adult , African Americans/statistics & numerical data , Antibodies, Viral/immunology , Betacoronavirus/immunology , Clinical Laboratory Techniques/methods , Clinical Laboratory Techniques/statistics & numerical data , Cohort Studies , Coronavirus Infections/blood , Coronavirus Infections/diagnosis , Coronavirus Infections/immunology , Coronavirus Infections/virology , Female , Hispanic Americans/statistics & numerical data , Humans , Immunoglobulin G/blood , Immunoglobulin G/immunology , Immunoglobulin M/blood , Immunoglobulin M/immunology , Pandemics , Philadelphia/epidemiology , Pneumonia, Viral/blood , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , Pregnancy , Pregnancy Complications, Infectious/blood , Pregnancy Complications, Infectious/immunology , Pregnancy Complications, Infectious/virology , Protein Domains/immunology , Seroepidemiologic Studies , Spike Glycoprotein, Coronavirus/immunology , Young Adult
15.
Infect Dis Poverty ; 9(1): 88, 2020 Jul 10.
Article in English | MEDLINE | ID: covidwho-690345

ABSTRACT

BACKGROUND: An outbreak of infection caused by SARS-CoV-2 recently has brought a great challenge to public health. Rapid identification of immune epitopes would be an efficient way to screen the candidates for vaccine development at the time of pandemic. This study aimed to predict the protective epitopes with bioinformatics methods and resources for vaccine development. METHODS: The genome sequence and protein sequences of SARS-CoV-2 were retrieved from the National Center for Biotechnology Information (NCBI) database. ABCpred and BepiPred servers were utilized for sequential B-cell epitope analysis. Discontinuous B-cell epitopes were predicted via DiscoTope 2.0 program. IEDB server was utilized for HLA-1 and HLA-2 binding peptides computation. Surface accessibility, antigenicity, and other important features of forecasted epitopes were characterized for immunogen potential evaluation. RESULTS: A total of 63 sequential B-cell epitopes on spike protein were predicted and 4 peptides (Spike315-324, Spike333-338, Spike648-663, Spike1064-1079) exhibited high antigenicity score and good surface accessibility. Ten residues within spike protein (Gly496, Glu498, Pro499, Thr500, Leu1141, Gln1142, Pro1143, Glu1144, Leu1145, Asp1146) are forecasted as components of discontinuous B-cell epitopes. The bioinformatics analysis of HLA binding peptides within nucleocapsid protein produced 81 and 64 peptides being able to bind MHC class I and MHC class II molecules respectively. The peptides (Nucleocapsid66-75, Nucleocapsid104-112) were predicted to bind a wide spectrum of both HLA-1 and HLA-2 molecules. CONCLUSIONS: B-cell epitopes on spike protein and T-cell epitopes within nucleocapsid protein were identified and recommended for developing a protective vaccine against SARS-CoV-2.


Subject(s)
Betacoronavirus/genetics , Betacoronavirus/immunology , Computational Biology/methods , Coronavirus Infections/prevention & control , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/immunology , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Viral Vaccines/immunology , Amino Acid Sequence , Coronavirus Infections/immunology , Coronavirus Infections/virology , Drug Design , Epitopes, B-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/chemistry , Humans , Immunogenicity, Vaccine/immunology , Models, Molecular , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , Sequence Alignment , Sequence Analysis , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Viral Envelope Proteins/immunology
16.
Front Immunol ; 11: 1663, 2020.
Article in English | MEDLINE | ID: covidwho-687238

ABSTRACT

A recent pandemic caused by a single-stranded RNA virus, COVID-19, initially discovered in China, is now spreading globally. This poses a serious threat that needs to be addressed immediately. Genome analysis of SARS-CoV-2 has revealed its close relation to SARS-coronavirus along with few changes in its spike protein. The spike protein aids in receptor binding and viral entry within the host and therefore represents a potential target for vaccine and therapeutic development. In the current study, the spike protein of SARS-CoV-2 was explored for potential immunogenic epitopes to design multi-epitope vaccine constructs. The S1 and S2 domains of spike proteins were analyzed, and two vaccine constructs were prioritized with T-cell and B-cell epitopes. We adapted a comprehensive predictive framework to provide novel insights into immunogenic epitopes of spike proteins, which can further be evaluated as potential vaccine candidates against COVID-19. Prioritized epitopes were then modeled using linkers and adjuvants, and respective 3D models were constructed to evaluate their physiochemical properties and their possible interactions with ACE2, HLA Superfamily alleles, TLR2, and TLR4.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/immunology , Coronavirus Infections/prevention & control , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/immunology , Pandemics/prevention & control , Pneumonia, Viral/immunology , Pneumonia, Viral/prevention & control , Viral Vaccines/immunology , Amino Acid Sequence , Coronavirus Infections/virology , Epitopes, B-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/chemistry , HLA Antigens/chemistry , HLA Antigens/immunology , Humans , Models, Chemical , Molecular Docking Simulation , Peptidyl-Dipeptidase A/chemistry , Peptidyl-Dipeptidase A/immunology , Pneumonia, Viral/virology , Protein Structure, Secondary , Protein Structure, Tertiary , Spike Glycoprotein, Coronavirus/immunology , Toll-Like Receptor 2/chemistry , Toll-Like Receptor 2/immunology , Toll-Like Receptor 4/chemistry , Toll-Like Receptor 4/immunology , Viral Vaccines/chemistry
17.
Antiviral Res ; 181: 104882, 2020 09.
Article in English | MEDLINE | ID: covidwho-684270

ABSTRACT

SARS-CoV-2 is a novel pandemic coronavirus that caused a global health and economic crisis. The development of efficient drugs and vaccines against COVID-19 requires detailed knowledge about SARS-CoV-2 biology. Several techniques to detect SARS-CoV-2 infection have been established, mainly based on counting infected cells by staining plaques or foci, or by quantifying the viral genome by PCR. These methods are laborious, time-consuming and expensive and therefore not suitable for a high sample throughput or rapid diagnostics. We here report a novel enzyme-based immunodetection assay that directly quantifies the amount of de novo synthesized viral spike protein within fixed and permeabilized cells. This in-cell ELISA enables a rapid and quantitative detection of SARS-CoV-2 infection in microtiter format, regardless of the virus isolate or target cell culture. It follows the established method of performing ELISA assays and does not require expensive instrumentation. Utilization of the in-cell ELISA allows to e.g. determine TCID50 of virus stocks, antiviral efficiencies (IC50 values) of drugs or neutralizing activity of sera. Thus, the in-cell spike ELISA represents a promising alternative to study SARS-CoV-2 infection and inhibition and may facilitate future research.


Subject(s)
Antibodies, Viral/immunology , Betacoronavirus/immunology , Coronavirus Infections/virology , Enzyme-Linked Immunosorbent Assay/methods , Pneumonia, Viral/virology , Severe Acute Respiratory Syndrome/virology , Spike Glycoprotein, Coronavirus/immunology , Animals , Betacoronavirus/isolation & purification , Chlorocebus aethiops , Coronavirus Infections/diagnosis , Humans , Pandemics , Pneumonia, Viral/diagnosis , Severe Acute Respiratory Syndrome/diagnosis , Spike Glycoprotein, Coronavirus/genetics , Vero Cells , Viral Plaque Assay
18.
Biophys Chem ; 265: 106441, 2020 10.
Article in English | MEDLINE | ID: covidwho-679608

ABSTRACT

The possibility of immobilizing a protein with antigenic properties on a solid support offers significant possibilities in the development of immunosensors and vaccine formulations. For both applications, the orientation of the antigen should ensure ready accessibility of the antibodies to the epitope. However, an experimental assessment of the orientational preferences necessarily proceeds through the preparation/isolation of the antigen, the immobilization on different surfaces and one or more biophysical characterization steps. To predict a priori whether favorable orientations can be achieved or not would allow one to select the most promising experimental routes, partly mitigating the time cost towards the final product. In this manuscript, we apply a simple computational model, based on united-residue modelling, to the prediction of the orientation of the receptor binding domain of the SARS-CoV-2 spike protein on surfaces commonly used in lateral-flow devices. These calculations can account for the experimental observation that direct immobilization on gold gives sufficient exposure of the epitope to obtain a response in immunochemical assays.


Subject(s)
Betacoronavirus/metabolism , Epitopes/chemistry , Models, Molecular , Spike Glycoprotein, Coronavirus/metabolism , Antigens/chemistry , Antigens/immunology , Antigens/metabolism , Epitopes/immunology , Molecular Docking Simulation , Protein Domains , Silicon Dioxide/chemistry , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Surface Properties
20.
Lancet ; 396(10249): 479-488, 2020 08 15.
Article in English | MEDLINE | ID: covidwho-666142

ABSTRACT

BACKGROUND: This is the first randomised controlled trial for assessment of the immunogenicity and safety of a candidate non-replicating adenovirus type-5 (Ad5)-vectored COVID-19 vaccine, aiming to determine an appropriate dose of the candidate vaccine for an efficacy study. METHODS: This randomised, double-blind, placebo-controlled, phase 2 trial of the Ad5-vectored COVID-19 vaccine was done in a single centre in Wuhan, China. Healthy adults aged 18 years or older, who were HIV-negative and previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection-free, were eligible to participate and were randomly assigned to receive the vaccine at a dose of 1 × 1011 viral particles per mL or 5 × 1010 viral particles per mL, or placebo. Investigators allocated participants at a ratio of 2:1:1 to receive a single injection intramuscularly in the arm. The randomisation list (block size 4) was generated by an independent statistician. Participants, investigators, and staff undertaking laboratory analyses were masked to group allocation. The primary endpoints for immunogenicity were the geometric mean titres (GMTs) of specific ELISA antibody responses to the receptor binding domain (RBD) and neutralising antibody responses at day 28. The primary endpoint for safety evaluation was the incidence of adverse reactions within 14 days. All recruited participants who received at least one dose were included in the primary and safety analyses. This study is registered with ClinicalTrials.gov, NCT04341389. FINDINGS: 603 volunteers were recruited and screened for eligibility between April 11 and 16, 2020. 508 eligible participants (50% male; mean age 39·7 years, SD 12·5) consented to participate in the trial and were randomly assigned to receive the vaccine (1 × 1011 viral particles n=253; 5 × 1010 viral particles n=129) or placebo (n=126). In the 1 × 1011 and 5 × 1010 viral particles dose groups, the RBD-specific ELISA antibodies peaked at 656·5 (95% CI 575·2-749·2) and 571·0 (467·6-697·3), with seroconversion rates at 96% (95% CI 93-98) and 97% (92-99), respectively, at day 28. Both doses of the vaccine induced significant neutralising antibody responses to live SARS-CoV-2, with GMTs of 19·5 (95% CI 16·8-22·7) and 18·3 (14·4-23·3) in participants receiving 1 × 1011 and 5 × 1010 viral particles, respectively. Specific interferon γ enzyme-linked immunospot assay responses post vaccination were observed in 227 (90%, 95% CI 85-93) of 253 and 113 (88%, 81-92) of 129 participants in the 1 × 1011 and 5 × 1010 viral particles dose groups, respectively. Solicited adverse reactions were reported by 183 (72%) of 253 and 96 (74%) of 129 participants in the 1 × 1011 and 5 × 1010 viral particles dose groups, respectively. Severe adverse reactions were reported by 24 (9%) participants in the 1 × 1011 viral particles dose group and one (1%) participant in the 5 × 1010 viral particles dose group. No serious adverse reactions were documented. INTERPRETATION: The Ad5-vectored COVID-19 vaccine at 5 × 1010 viral particles is safe, and induced significant immune responses in the majority of recipients after a single immunisation. FUNDING: National Key R&D Programme of China, National Science and Technology Major Project, and CanSino Biologics.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Viral Vaccines/adverse effects , Viral Vaccines/immunology , Adenoviridae , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , China , Coronavirus Infections/immunology , Double-Blind Method , Female , Genetic Vectors , Humans , Male , Middle Aged , Spike Glycoprotein, Coronavirus/immunology , T-Lymphocytes/immunology , Viral Vaccines/administration & dosage , Young Adult
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