Background The ongoing outbreak of the recently emerged novel coronavirus (2019-nCoV) poses a challenge for public health laboratories as virus isolates are unavailable while there is growing evidence that the outbreak is more widespread than initially thought, and international spread through travellers does already occur. Aim We aimed to develop and deploy robust diagnostic methodology for use in public health laboratory settings without having virus material available. Methods Here we present a validated diagnostic workflow for 2019-nCoV, its design relying on close genetic relatedness of 2019-nCoV with SARS coronavirus, making use of synthetic nucleic acid technology. Results The workflow reliably detects 2019-nCoV, and further discriminates 2019-nCoV from SARS-CoV. Through coordination between academic and public laboratories, we confirmed assay exclusivity based on 297 original clinical specimens containing a full spectrum of human respiratory viruses. Control material is made available through European Virus Archive – Global (EVAg), a European Union infrastructure project. Conclusion The present study demonstrates the enormous response capacity achieved through coordination of academic and public laboratories in national and European research networks.

/pdf/detection-of-2019-novel-coronavirus-2019-ncov-by-real-time-5an3azdech.pdf

Detection of 2019 novel coronavirus (2019-nCoV) by real-time RT-PCR.

The present outbreak of a coronavirus-associated acute respiratory disease called coronavirus disease 19 (COVID-19) is the third documented spillover of an animal coronavirus to humans in only two decades that has resulted in a major epidemic. The Coronaviridae Study Group (CSG) of the International Committee on Taxonomy of Viruses, which is responsible for developing the classification of viruses and taxon nomenclature of the family Coronaviridae, has assessed the placement of the human pathogen, tentatively named 2019-nCoV, within the Coronaviridae. Based on phylogeny, taxonomy and established practice, the CSG recognizes this virus as forming a sister clade to the prototype human and bat severe acute respiratory syndrome coronaviruses (SARS-CoVs) of the species Severe acute respiratory syndrome-related coronavirus, and designates it as SARS-CoV-2. In order to facilitate communication, the CSG proposes to use the following naming convention for individual isolates: SARS-CoV-2/host/location/isolate/date. While the full spectrum of clinical manifestations associated with SARS-CoV-2 infections in humans remains to be determined, the independent zoonotic transmission of SARS-CoV and SARS-CoV-2 highlights the need for studying viruses at the species level to complement research focused on individual pathogenic viruses of immediate significance. This will improve our understanding of virus–host interactions in an ever-changing environment and enhance our preparedness for future outbreaks.

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The species Severe acute respiratory syndrome-related coronavirus: classifying 2019-nCoV and naming it SARS-CoV-2

A previously unknown coronavirus was isolated from the sputum of a 60-year-old man who presented with acute pneumonia and subsequent renal failure with a fatal outcome in Saudi Arabia. The virus (called HCoV-EMC) replicated readily in cell culture, producing cytopathic effects of rounding, detachment, and syncytium formation. The virus represents a novel betacoronavirus species. The closest known relatives are bat coronaviruses HKU4 and HKU5. Here, the clinical data, virus isolation, and molecular identification are presented. The clinical picture was remarkably similar to that of the severe acute respiratory syndrome (SARS) outbreak in 2003 and reminds us that animal coronaviruses can cause severe disease in humans.

http://iacld.ir/DL/elm/isolationofanovelcoronavirusfromamanwithpneumoniainsaudiarabia.pdf

Isolation of a Novel Coronavirus from a Man with Pneumonia in Saudi Arabia

What do a seventeenth-century mortality table (whose causes of death include "fainted in a bath," "frighted," and "itch"); the identification of South Africans during apartheid as European, Asian, colored, or black; and the separation of machine- from hand-washables have in common? All are examples of classification -- the scaffolding of information infrastructures. In Sorting Things Out, Geoffrey C. Bowker and Susan Leigh Star explore the role of categories and standards in shaping the modern world. In a clear and lively style, they investigate a variety of classification systems, including the International Classification of Diseases, the Nursing Interventions Classification, race classification under apartheid in South Africa, and the classification of viruses and of tuberculosis. The authors emphasize the role of invisibility in the process by which classification orders human interaction. They examine how categories are made and kept invisible, and how people can change this invisibility when necessary. They also explore systems of classification as part of the built information environment. Much as an urban historian would review highway permits and zoning decisions to tell a city's story, the authors review archives of classification design to understand how decisions have been made. Sorting Things Out has a moral agenda, for each standard and category valorizes some point of view and silences another. Standards and classifications produce advantage or suffering. Jobs are made and lost; some regions benefit at the expense of others. How these choices are made and how we think about that process are at the moral and political core of this work. The book is an important empirical source for understanding the building of information infrastructures.

https://www.reciis.icict.fiocruz.br/index.php/reciis/article/download/794/1436

Sorting Things Out: Classification and Its Consequences

https://www.cell.com/cell/pdf/S0092-8674(00)80205-6.pdf

Core structure of GP41 from the HIV envelope glycoprotein

The practical need to partition the world of viruses into distinguishable, universally agreed upon entities is the ultimate justification for developing a virus classification system. Since 1971, the International Committee on Taxonomy of Viruses (ICTV) operating on behalf of the world community of virologists has taken on the task of developing a single, universal taxonomic scheme for all viruses infecting animals (vertebrate, invertebrates, and protozoa), plants (higher plants and algae), fungi, bacteria, and archaea. The current report builds on the accumulated taxonomic construction of the eight previous reports dating back to 1971 and records the proceedings of the Committee since publication of the last report in 2005. Representing the work of more than 500 virologists worldwide, this report is the authoritative reference for virus organization, distinction, and structure.

Virus taxonomy: classification and nomenclature of viruses. Seventh report of the International Committee on Taxonomy of Viruses.

Most continuous antigenic determinants of tobacco mosaic virus protein (TMVP), myoglobin and lysozyme correspond to those surface regions in the protein structure, as determined by X-ray crystallography, which possess a run of high-temperature factors along the polypeptide backbone, that is, a high segmental mobility. The mobility of an antigenic determinant may make it easier to adjust to a pre-existing antibody site not fashioned to fit the exact geometry of a protein. The correlation found between temperature factors and antigenicity is better than that between hydrophilicity and antigenicity.

Correlation between segmental mobility and the location of antigenic determinants in proteins

Synthetic peptides as antigens: Pitfalls of conjugation methods

Three analogues of the model peptide of sequence IRGERA corresponding to the COOH-terminal residues 130-135 of histone H3 were synthesized, and their antigenicity, immunogenicity, and resistance to trypsin were compared to those of the natural L-peptide. The three analogues correspond to the D-enantiomer, containing only D-residues, and two retro-peptides containing NH-CO bonds instead of natural peptide bonds. The chirality of each residue was maintained in the retro-peptide and inverted in the retro-inverso-peptide. Antibodies to the four peptide analogues were produced by injecting BALB/c mice with peptides covalently coupled to small unilamellar liposomes containing monophosphoryl lipid A. Each of the four peptide analogues induced IgG antibodies of various subclasses. The IgG3 antibodies reacted similarly with the four analogues, whereas antibodies of the IgG1, IgG2a, and IgG2b isotypes showed strong conformational preferences for certain peptides. The retro-inverso-peptide IRGERA mimicked the structure and antigenic activity of the natural L-peptide but not of the D- and retro-peptides, whereas the retro-peptide IRGERA mimicked the D-peptide but not the L- and retro-inverso-peptides. The equilibrium affinity constants (Ka) of three monoclonal antibodies generated against the L- and D-peptides with respect to the four peptide analogues were measured in a biosensor system. Large differences in Ka values were observed when each monoclonal antibody was tested with respect to the four peptides. The use of retro-inverso-peptides to replace natural L-peptides is likely to find many applications in immunodiagnosis and as potential synthetic vaccines.

https://www.pnas.org/content/pnas/91/21/9765.full.pdf

Antigenic mimicry of natural L-peptides with retro-inverso-peptidomimetics.

Publisher Summary This chapter describes epitopes that are considered as “functional epitopes”—that is, portions or fragments of a protein that are able to bind to antibody in an immunoassay—and not as “contact epitopes” or “energetic epitopes” identifiable only in structural studies. The most common way of classifying epitopes is into continuous and discontinuous epitopes. The label “continuous epitope” is given to any short linear peptide fragment of an antigen that is able to bind to antibodies raised against the intact protein. In most cases, these antibodies cross-react only weakly with linear peptide fragment of the antigen. A more extreme viewpoint has been advocated, according to which all continuous epitopes represent “unfoldons”—that is, unfolded regions of the antigen that cross-react only with antibodies specific for the denatured protein. Such antibodies may be present in antisera raised against the protein, because some of the antigen molecules used for immunization is denatured or they could be obtained by immunization with peptide fragments.

M.H.V. Van Regenmortel

Papers

Virus taxonomy: classification and nomenclature of viruses. Seventh report of the International Committee on Taxonomy of Viruses.

Correlation between segmental mobility and the location of antigenic determinants in proteins

Synthetic peptides as antigens: Pitfalls of conjugation methods

Antigenic mimicry of natural L-peptides with retro-inverso-peptidomimetics.

Predicting location of continuous epitopes in proteins from their primary structures