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1.
PLoS One ; 16(11): e0259165, 2021.
Article in English | MEDLINE | ID: covidwho-1581791

ABSTRACT

The rapid, sensitive and specific detection of SARS-CoV-2 is critical in responding to the current COVID-19 outbreak. In this proof-of-concept study, we explored the potential of targeted mass spectrometry (MS) based proteomics for the detection of SARS-CoV-2 proteins in both research samples and clinical specimens. First, we assessed the limit of detection for several SARS-CoV-2 proteins by parallel reaction monitoring (PRM) MS in infected Vero E6 cells. For tryptic peptides of Nucleocapsid protein, the limit of detection was estimated to be in the mid-attomole range (9E-13 g). Next, this PRM methodology was applied to the detection of viral proteins in various COVID-19 patient clinical specimens, such as sputum and nasopharyngeal swabs. SARS-CoV-2 proteins were detected in these samples with high sensitivity in all specimens with PCR Ct values <24 and in several samples with higher CT values. A clear relationship was observed between summed MS peak intensities for SARS-CoV-2 proteins and Ct values reflecting the abundance of viral RNA. Taken together, these results suggest that targeted MS based proteomics may have the potential to be used as an additional tool in COVID-19 diagnostics.


Subject(s)
COVID-19/diagnosis , Proteomics , SARS-CoV-2/isolation & purification , Viral Proteins/isolation & purification , Animals , COVID-19/pathology , COVID-19/virology , Chlorocebus aethiops , Humans , Mass Spectrometry , Nucleocapsid/genetics , Nucleocapsid/isolation & purification , Phosphoproteins/genetics , Phosphoproteins/isolation & purification , Proteome/genetics , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Sputum/virology , Vero Cells , Viral Proteins/genetics
2.
J Clin Immunol ; 2021 Nov 12.
Article in English | MEDLINE | ID: covidwho-1509277

ABSTRACT

PURPOSE: To study the effect of interferon-α2 auto-antibodies (IFN-α2 Abs) on clinical and virological outcomes in critically ill COVID-19 patients and the risk of IFN-α2 Abs transfer during convalescent plasma treatment. METHODS: Sera from healthy controls, cases of COVID-19, and other respiratory illness were tested for IFN-α2 Abs by ELISA and a pseudo virus-based neutralization assay. The effects of disease severity, sex, and age on the risk of having neutralizing IFN-α2 Abs were determined. Longitudinal analyses were performed to determine association between IFN-α2 Abs and survival and viral load and whether serum IFN-α2 Abs appeared after convalescent plasma transfusion. RESULTS: IFN-α2 neutralizing sera were found only in COVID-19 patients, with proportions increasing with disease severity and age. In the acute stage of COVID-19, all sera from patients with ELISA-detected IFN-α2 Abs (13/164, 7.9%) neutralized levels of IFN-α2 exceeding physiological concentrations found in human plasma and this was associated with delayed viral clearance. Convalescent plasma donors that were anti-IFN-α2 ELISA positive (3/118, 2.5%) did not neutralize the same levels of IFN-α2. Neutralizing serum IFN-α2 Abs were associated with delayed viral clearance from the respiratory tract. CONCLUSIONS: IFN-α2 Abs were detected by ELISA and neutralization assay in COVID-19 patients, but not in ICU patients with other respiratory illnesses. The presence of neutralizing IFN-α2 Abs in critically ill COVID-19 is associated with delayed viral clearance. IFN-α2 Abs in COVID-19 convalescent plasma donors were not neutralizing in the conditions tested.

3.
Nat Commun ; 12(1): 5498, 2021 09 17.
Article in English | MEDLINE | ID: covidwho-1428814

ABSTRACT

Rapid identification of host genes essential for virus replication may expedite the generation of therapeutic interventions. Genetic screens are often performed in transformed cell lines that poorly represent viral target cells in vivo, leading to discoveries that may not be translated to the clinic. Intestinal organoids are increasingly used to model human disease and are amenable to genetic engineering. To discern which host factors are reliable anti-coronavirus therapeutic targets, we generate mutant clonal IOs for 19 host genes previously implicated in coronavirus biology. We verify ACE2 and DPP4 as entry receptors for SARS-CoV/SARS-CoV-2 and MERS-CoV respectively. SARS-CoV-2 replication in IOs does not require the endosomal Cathepsin B/L proteases, but specifically depends on the cell surface protease TMPRSS2. Other TMPRSS family members were not essential. The newly emerging coronavirus variant B.1.1.7, as well as SARS-CoV and MERS-CoV similarly depended on TMPRSS2. These findings underscore the relevance of non-transformed human models for coronavirus research, identify TMPRSS2 as an attractive pan-coronavirus therapeutic target, and demonstrate that an organoid knockout biobank is a valuable tool to investigate the biology of current and future emerging coronaviruses.


Subject(s)
Angiotensin-Converting Enzyme 2/genetics , Biological Specimen Banks , CRISPR-Cas Systems , Coronavirus , Dipeptidyl Peptidase 4/genetics , Organoids/metabolism , Serine Endopeptidases/genetics , COVID-19 , Cell Line , Humans , Middle East Respiratory Syndrome Coronavirus , SARS-CoV-2 , Transcriptome , Virus Replication
4.
Elife ; 102021 04 09.
Article in English | MEDLINE | ID: covidwho-1389777

ABSTRACT

Virus propagation methods generally use transformed cell lines to grow viruses from clinical specimens, which may force viruses to rapidly adapt to cell culture conditions, a process facilitated by high viral mutation rates. Upon propagation in VeroE6 cells, SARS-CoV-2 may mutate or delete the multibasic cleavage site (MBCS) in the spike protein. Previously, we showed that the MBCS facilitates serine protease-mediated entry into human airway cells (Mykytyn et al., 2021). Here, we report that propagating SARS-CoV-2 on the human airway cell line Calu-3 - that expresses serine proteases - prevents cell culture adaptations in the MBCS and directly adjacent to the MBCS (S686G). Similar results were obtained using a human airway organoid-based culture system for SARS-CoV-2 propagation. Thus, in-depth knowledge on the biology of a virus can be used to establish methods to prevent cell culture adaptation.


Subject(s)
Epithelial Cells , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/genetics , Virus Cultivation/methods , Virus Internalization , Animals , Cell Line , Chlorocebus aethiops , Epithelial Cells/cytology , Epithelial Cells/metabolism , Epithelial Cells/virology , Humans , Proteolysis , Respiratory System/cytology , Respiratory System/virology , Serine Proteases/metabolism
5.
Dis Model Mech ; 14(6)2021 06 01.
Article in English | MEDLINE | ID: covidwho-1295507

ABSTRACT

The COVID-19 pandemic has emphasised the need to develop effective treatments to combat emerging viruses. Model systems that poorly represent a virus' cellular environment, however, may impede research and waste resources. Collaborations between cell biologists and virologists have led to the rapid development of representative organoid model systems to study severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We believe that lung organoids, in particular, have advanced our understanding of SARS-CoV-2 pathogenesis, and have laid a foundation to study future pandemic viruses and develop effective treatments.


Subject(s)
COVID-19/virology , Lung/virology , Models, Biological , Organoids/virology , SARS-CoV-2 , Animals , COVID-19/epidemiology , Humans , Pandemics , Pulmonary Alveoli/virology , Research Design/trends , SARS-CoV-2/pathogenicity
6.
J Infect Dis ; 223(12): 2020-2028, 2021 06 15.
Article in English | MEDLINE | ID: covidwho-1246725

ABSTRACT

Effective clinical intervention strategies for coronavirus disease 2019 (COVID-19) are urgently needed. Although several clinical trials have evaluated use of convalescent plasma containing virus-neutralizing antibodies, levels of neutralizing antibodies are usually not assessed and the effectiveness has not been proven. We show that hamsters treated prophylactically with a 1:2560 titer of human convalescent plasma or a 1:5260 titer of monoclonal antibody were protected against weight loss, had a significant reduction of virus replication in the lungs, and showed reduced pneumonia. Interestingly, this protective effect was lost with a titer of 1:320 of convalescent plasma. These data highlight the importance of screening plasma donors for high levels of neutralizing antibodies. Our data show that prophylactic administration of high levels of neutralizing antibody, either monoclonal or from convalescent plasma, prevent severe SARS-CoV-2 pneumonia in a hamster model, and could be used as an alternative or complementary to other antiviral treatments for COVID-19.


Subject(s)
Antibodies, Monoclonal/therapeutic use , Antibodies, Neutralizing/therapeutic use , COVID-19/therapy , Lung/pathology , SARS-CoV-2/immunology , Virus Replication/drug effects , Animals , Antibodies, Monoclonal/administration & dosage , Antibodies, Neutralizing/administration & dosage , COVID-19/immunology , Cricetinae , Disease Models, Animal , Humans , Immunization, Passive , Lung/drug effects , Virus Shedding/drug effects , Weight Loss/drug effects
7.
Elife ; 102021 01 04.
Article in English | MEDLINE | ID: covidwho-1063492

ABSTRACT

Coronavirus entry is mediated by the spike protein that binds the receptor and mediates fusion after cleavage by host proteases. The proteases that mediate entry differ between cell lines, and it is currently unclear which proteases are relevant in vivo. A remarkable feature of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike is the presence of a multibasic cleavage site (MBCS), which is absent in the SARS-CoV spike. Here, we report that the SARS-CoV-2 spike MBCS increases infectivity on human airway organoids (hAOs). Compared with SARS-CoV, SARS-CoV-2 entered faster into Calu-3 cells and, more frequently, formed syncytia in hAOs. Moreover, the MBCS increased entry speed and plasma membrane serine protease usage relative to cathepsin-mediated endosomal entry. Blocking serine proteases, but not cathepsins, effectively inhibited SARS-CoV-2 entry and replication in hAOs. Our findings demonstrate that SARS-CoV-2 enters relevant airway cells using serine proteases, and suggest that the MBCS is an adaptation to this viral entry strategy.


Subject(s)
Organoids/virology , Respiratory System/virology , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/chemistry , Virus Internalization , Amino Acid Motifs , Animals , COVID-19/virology , Cell Fusion , Cell Line, Tumor , Chlorocebus aethiops , Humans , SARS Virus/chemistry , SARS Virus/physiology , SARS-CoV-2/chemistry , Serine Endopeptidases , Vero Cells
8.
Nat Commun ; 12(1): 267, 2021 01 11.
Article in English | MEDLINE | ID: covidwho-1019818

ABSTRACT

Key questions in COVID-19 are the duration and determinants of infectious virus shedding. Here, we report that infectious virus shedding is detected by virus cultures in 23 of the 129 patients (17.8%) hospitalized with COVID-19. The median duration of shedding infectious virus is 8 days post onset of symptoms (IQR 5-11) and drops below 5% after 15.2 days post onset of symptoms (95% confidence interval (CI) 13.4-17.2). Multivariate analyses identify viral loads above 7 log10 RNA copies/mL (odds ratio [OR] of 14.7 (CI 3.57-58.1; p < 0.001) as independently associated with isolation of infectious SARS-CoV-2 from the respiratory tract. A serum neutralizing antibody titre of at least 1:20 (OR of 0.01 (CI 0.003-0.08; p < 0.001) is independently associated with non-infectious SARS-CoV-2. We conclude that quantitative viral RNA load assays and serological assays could be used in test-based strategies to discontinue or de-escalate infection prevention and control precautions.


Subject(s)
COVID-19/diagnosis , COVID-19/virology , SARS-CoV-2 , Virus Shedding , Aged , COVID-19 Testing , Female , Humans , Male , Middle Aged , Multivariate Analysis , Odds Ratio , RNA, Viral , Respiratory System/virology , Viral Load
9.
Emerg Microbes Infect ; 10(1): 1-7, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-990475

ABSTRACT

Transmission of severe acute respiratory coronavirus-2 (SARS-CoV-2) between livestock and humans is a potential public health concern. We demonstrate the susceptibility of rabbits to SARS-CoV-2, which excrete infectious virus from the nose and throat upon experimental inoculation. Therefore, investigations on the presence of SARS-CoV-2 in farmed rabbits should be considered.


Subject(s)
COVID-19/transmission , Rabbits/virology , SARS-CoV-2/isolation & purification , Angiotensin-Converting Enzyme 2/physiology , Animals , COVID-19/etiology , COVID-19/veterinary , Disease Susceptibility/veterinary , Female , HEK293 Cells , Humans , Virus Shedding
10.
Sci Rep ; 10(1): 21894, 2020 12 14.
Article in English | MEDLINE | ID: covidwho-977275

ABSTRACT

The rapid emergence of SARS-CoV-2, the causative agent of COVID-19, and its dissemination globally has caused an unprecedented strain on public health. Animal models are urgently being developed for SARS-CoV-2 to aid rational design of vaccines and therapeutics. Immunohistochemistry and in situ hybridisation techniques that facilitate reliable and reproducible detection of SARS-CoV and SARS-CoV-2 viral products in formalin-fixed paraffin-embedded (FFPE) specimens would be of great utility. A selection of commercial antibodies generated against SARS-CoV spike protein and nucleoprotein, double stranded RNA, and RNA probe for spike genes were evaluated for the ability to detect FFPE infected cells. We also tested both heat- and enzymatic-mediated virus antigen retrieval methods to determine the optimal virus antigen recovery as well as identifying alternative retrieval methods to enable flexibility of IHC methods. In addition to using native virus infected cells as positive control material, the evaluation of non-infected cells expressing coronavirus (SARS, MERS) spike as a biosecure alternative to assays involving live virus was undertaken. Optimized protocols were successfully applied to experimental animal-derived tissues. The diverse techniques for virus detection and control material generation demonstrated in this study can be applied to investigations of coronavirus pathogenesis and therapeutic research in animal models.


Subject(s)
Antigens, Viral/immunology , COVID-19 Testing , COVID-19 , Immunohistochemistry , SARS-CoV-2/isolation & purification , Animals , Antibodies, Monoclonal/immunology , Antibodies, Viral/immunology , COVID-19/diagnosis , COVID-19/virology , Chlorocebus aethiops , Ferrets , In Situ Hybridization , RNA Probes/immunology , SARS Virus/isolation & purification , Vero Cells
11.
EMBO J ; 40(5): e105912, 2021 03 01.
Article in English | MEDLINE | ID: covidwho-962496

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), which may result in acute respiratory distress syndrome (ARDS), multiorgan failure, and death. The alveolar epithelium is a major target of the virus, but representative models to study virus host interactions in more detail are currently lacking. Here, we describe a human 2D air-liquid interface culture system which was characterized by confocal and electron microscopy and single-cell mRNA expression analysis. In this model, alveolar cells, but also basal cells and rare neuroendocrine cells, are grown from 3D self-renewing fetal lung bud tip organoids. These cultures were readily infected by SARS-CoV-2 with mainly surfactant protein C-positive alveolar type II-like cells being targeted. Consequently, significant viral titers were detected and mRNA expression analysis revealed induction of type I/III interferon response program. Treatment of these cultures with a low dose of interferon lambda 1 reduced viral replication. Hence, these cultures represent an experimental model for SARS-CoV-2 infection and can be applied for drug screens.


Subject(s)
Alveolar Epithelial Cells/metabolism , COVID-19/metabolism , Models, Biological , Organoids/metabolism , SARS-CoV-2/physiology , Virus Replication , Alveolar Epithelial Cells/pathology , Alveolar Epithelial Cells/virology , Animals , COVID-19/virology , Chlorocebus aethiops , Gene Expression Regulation , Humans , Interferon Type I/biosynthesis , Interferons/biosynthesis , Organoids/pathology , Organoids/virology , Vero Cells
12.
Emerg Infect Dis ; 26(7):1478-1488, 2020.
Article in English | MEDLINE | ID: covidwho-655091

ABSTRACT

A new coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has recently emerged to cause a human pandemic. Although molecular diagnostic tests were rapidly developed, serologic assays are still lacking, yet urgently needed. Validated serologic assays are needed for contact tracing, identifying the viral reservoir, and epidemiologic studies. We developed serologic assays for detection of SARS-CoV-2 neutralizing, spike protein-specific, and nucleocapsid-specific antibodies. Using serum samples from patients with PCR-confirmed SARS-CoV-2 infections, other coronaviruses, or other respiratory pathogenic infections, we validated and tested various antigens in different in-house and commercial ELISAs. We demonstrated that most PCR-confirmed SARS-CoV-2-infected persons seroconverted by 2 weeks after disease onset. We found that commercial S1 IgG or IgA ELISAs were of lower specificity, and sensitivity varied between the 2 assays;the IgA ELISA showed higher sensitivity. Overall, the validated assays described can be instrumental for detection of SARS-CoV-2-specific antibodies for diagnostic, seroepidemiologic, and vaccine evaluation studies.

13.
Nat Commun ; 11(1): 3496, 2020 07 08.
Article in English | MEDLINE | ID: covidwho-640239

ABSTRACT

SARS-CoV-2, a coronavirus that emerged in late 2019, has spread rapidly worldwide, and information about the modes of transmission of SARS-CoV-2 among humans is critical to apply appropriate infection control measures and to slow its spread. Here we show that SARS-CoV-2 is transmitted efficiently via direct contact and via the air (via respiratory droplets and/or aerosols) between ferrets, 1 to 3 days and 3 to 7 days after exposure respectively. The pattern of virus shedding in the direct contact and indirect recipient ferrets is similar to that of the inoculated ferrets and infectious virus is isolated from all positive animals, showing that ferrets are productively infected via either route. This study provides experimental evidence of robust transmission of SARS-CoV-2 via the air, supporting the implementation of community-level social distancing measures currently applied in many countries in the world and informing decisions on infection control measures in healthcare settings.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/transmission , Coronavirus Infections/virology , Pneumonia, Viral/transmission , Pneumonia, Viral/virology , Animals , Antibodies, Viral/blood , Betacoronavirus/genetics , Betacoronavirus/immunology , Betacoronavirus/isolation & purification , COVID-19 , Disease Models, Animal , Ferrets , Genome, Viral/genetics , Humans , Pandemics , Rectum/virology , Respiratory System/virology , SARS-CoV-2 , Sequence Analysis, RNA , Virus Shedding
14.
Science ; 369(6499): 50-54, 2020 07 03.
Article in English | MEDLINE | ID: covidwho-154670

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause coronavirus disease 2019 (COVID-19), an influenza-like disease that is primarily thought to infect the lungs with transmission through the respiratory route. However, clinical evidence suggests that the intestine may present another viral target organ. Indeed, the SARS-CoV-2 receptor angiotensin-converting enzyme 2 (ACE2) is highly expressed on differentiated enterocytes. In human small intestinal organoids (hSIOs), enterocytes were readily infected by SARS-CoV and SARS-CoV-2, as demonstrated by confocal and electron microscopy. Enterocytes produced infectious viral particles, whereas messenger RNA expression analysis of hSIOs revealed induction of a generic viral response program. Therefore, the intestinal epithelium supports SARS-CoV-2 replication, and hSIOs serve as an experimental model for coronavirus infection and biology.


Subject(s)
Betacoronavirus/physiology , Enterocytes/virology , Ileum/virology , Virus Replication , Angiotensin-Converting Enzyme 2 , Betacoronavirus/ultrastructure , Cell Culture Techniques , Cell Differentiation , Cell Lineage , Cell Proliferation , Culture Media , Enterocytes/metabolism , Enterocytes/ultrastructure , Gene Expression , Humans , Ileum/metabolism , Ileum/ultrastructure , Lung/virology , Male , Organoids , Peptidyl-Dipeptidase A/genetics , Peptidyl-Dipeptidase A/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptors, Virus/genetics , Receptors, Virus/metabolism , Respiratory Mucosa/virology , SARS Virus/physiology , SARS-CoV-2
15.
Science ; 368(6494): 1012-1015, 2020 05 29.
Article in English | MEDLINE | ID: covidwho-71867

ABSTRACT

The current pandemic coronavirus, severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), was recently identified in patients with an acute respiratory syndrome, coronavirus disease 2019 (COVID-19). To compare its pathogenesis with that of previously emerging coronaviruses, we inoculated cynomolgus macaques with SARS-CoV-2 or Middle East respiratory syndrome (MERS)-CoV and compared the pathology and virology with historical reports of SARS-CoV infections. In SARS-CoV-2-infected macaques, virus was excreted from nose and throat in the absence of clinical signs and detected in type I and II pneumocytes in foci of diffuse alveolar damage and in ciliated epithelial cells of nasal, bronchial, and bronchiolar mucosae. In SARS-CoV infection, lung lesions were typically more severe, whereas they were milder in MERS-CoV infection, where virus was detected mainly in type II pneumocytes. These data show that SARS-CoV-2 causes COVID-19-like disease in macaques and provides a new model to test preventive and therapeutic strategies.


Subject(s)
Betacoronavirus/pathogenicity , Coronavirus Infections/pathology , Coronavirus Infections/virology , Disease Models, Animal , Lung/pathology , Macaca fascicularis , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , Aging , Animals , Betacoronavirus/isolation & purification , Betacoronavirus/physiology , COVID-19 , Female , Lung/virology , Middle East Respiratory Syndrome Coronavirus/isolation & purification , Middle East Respiratory Syndrome Coronavirus/physiology , Pandemics , Pulmonary Alveoli/pathology , Pulmonary Alveoli/virology , Respiratory System/pathology , Respiratory System/virology , SARS Virus/isolation & purification , SARS Virus/physiology , SARS-CoV-2 , Severe Acute Respiratory Syndrome/pathology , Severe Acute Respiratory Syndrome/virology , Virus Replication , Virus Shedding
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