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Order Articulavirales
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
The order is of extremely high medical importance, because of the continuous healthcare concern associated with influenza infections. There are four types of influenza virus, namely types A, B, C, and D belonging to the genera Alphainfluenzavirus, Betainfluenzavirus, Gammainfluenzavirus, and Deltainfluenzavirus, respectively. The influenza A and B viruses are clinically relevant for humans. Influenza A viruses are responsible for annual epidemics and all known influenza pandemics. The influenza B virus is primarily a human pathogen, which is not associated with an animal reservoir. It causes similar symptoms and disease as the influenza A virus. However, the frequency of the severe cases of influenza B infections appears to be significantly lower than that of influenza A. As to the influenza C, well-defined outbreaks have rarely been detected in humans, and the virus is rarely associated with severe syndromes. Most people have antibody to the influenza C virus by early adulthood, and influenza C is not included in the current influenza vaccine formulations. For more information and references, reviews of Pushko et al. (2008), Pushko and Tumpey (2015), and Pushko and Tretyakova (2020) are recommended.
Determination of Antiviral Activity
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
The Orthomyxoviridae family contains only the influenza viruses, which have long been considered primary targets for antiviral chemotherapy. The serious epidemic respiratory infections caused by influenza A and B viruses, as well as the sporadic infections caused by influenza C virus, have been well documented [183,184],
RAT α 2 -Macroglobulin and Related α-Macroglobulins in the Acute Phase Response
Published in Andrzej Mackiewicz, Irving Kushner, Heinz Baumann, Acute Phase Proteins, 2020
Rat α1-M and α1-I3 (murinoglobulin) have been identified as the proteins responsible for inhibition of infuenza C virus hemagglutination.76,77 This activity was destroyed by treatment of either protein with sodium hydroxide or methylamine, but not by oxidation with sodium metaperiodate. The activity was also destroyed by treatment with neuraminidase from Arthrobacter ureafaciens. These results suggest that the native slow forms of the proteins have a specific type of sialic acid residue at the binding site which is no longer exposed following the conformational changes brought about by cleavage of the thioester bond or alkaline denaturation. Evidence was presented that this binding site was very similar to the specific influenza C virus binding sites erythrocytes. Since only normal rat serum was used, it is not clear whether rat α2-M also shares this property. Recently, guinea pig and horse α2-M have also been shown to be potent infuenza virus hemagglutination inhibitors because of the presence of 4-O-acetyl-N-acetylneuraminic acid residues in their N-linked carbohydate side chains.78
Challenges in the development of egg-independent vaccines for influenza
Published in Expert Review of Vaccines, 2019
Claudia Maria Trombetta, Serena Marchi, Ilaria Manini, Giacomo Lazzeri, Emanuele Montomoli
Influenza viruses belong to the Orthomyxoviridae family and are divided into four genera (A, B, C and D) based on antigenic differences in the viral nucleoprotein and matrix protein (M). Influenza A viruses (IAVs) infect a wide range of avian and mammalian species, including humans. Influenza B virus (IBV) is exclusive to humans, as is influenza C virus, which causes very mild or asymptomatic infections, especially during childhood. The recently discovered influenza D virus has been isolated from pigs and cows, and so far there is no evidence of infection or illness in humans [1–7].
Comparative evaluation of a dual-target real-time RT-PCR assay for COVID-19 diagnosis and assessment of performance in pooled saliva and nasopharyngeal swab samples
Published in Expert Review of Molecular Diagnostics, 2021
Cyril C. Y. Yip, Kit-Hang Leung, Anthony C. K. Ng, Kwok-Hung Chan, Kelvin K. W. To, Jasper F. W Chan, Ivan F. N. Hung, Vincent C. C. Cheng, Siddharth Sridhar
Serial twofold dilutions of total nucleic acid (TNA) extracted from a Qnostics SARS-CoV-2 Medium Q Control (RANDOX, UK) were used for analytical sensitivity or limit-of-detection (LOD) evaluation. Different concentrations of TNA extracted from a SARS-CoV-2 culture isolate stock (1.8 × 107 TCID50/mL) isolated from the nasopharyngeal aspirate (NPA) of a patient with COVID-19 in Hong Kong were used for imprecision evaluation [16–18]. Each concentration was tested in triplicate in single run for intra-assay, and tested over two independent runs (each run with triplicate) for inter-assay imprecision evaluation. TNAs extracted from a clinical respiratory specimen positive for human coronavirus HKU1 (HCoV-HKU1) and 17 culture isolates of SARS-CoV, MERS-CoV, HCoV-OC43, HCoV-229E, HCoV-NL63, influenza A ((H1N1)pdm09 and H3N2) viruses, influenza B virus, influenza C virus, respiratory syncytial virus, human metapneumovirus, parainfluenza virus types 1–4, human rhinovirus, and human adenovirus were used for analytical specificity evaluation [19]. For diagnostic performance evaluation, we retrieved 296 clinical specimens obtained for initial diagnostic evaluation of hospitalized patients with suspected COVID-19. These included 255 respiratory tract specimens (NPA, NPS, throat swab, deep throat saliva or sputum) and 41 non-respiratory specimens (conjunctival swab, rectal swab, or stool). The male: female ratio was 136:160 and patients’ median age was 59.5 years (range: 3 months – 99 years). Some of these specimens were previously used in other assay evaluations published by our group [14,15,20]. In addition to clinical specimens, three proficiency testing (PT) samples from College of American Pathologist (CAP) and eight PT samples from Quality Control for Molecular Diagnostics (QCMD) with different concentrations of SARS-CoV-2 or negative for SARS-CoV-2 were also evaluated.
Toward the identification of ZDHHC enzymes required for palmitoylation of viral protein as potential drug targets
Published in Expert Opinion on Drug Discovery, 2020
Mohamed Rasheed Gadalla, Michael Veit
Protein palmitoylation was first described for a viral spike protein, the G-protein of vesicular stomatitis virus [32]. It rapidly turned out that (almost) every enveloped virus contains at least one S-acylated glycoprotein [33–35]. Basic biochemical features of S-acylation, such as the role of acyl-CoA as lipid donor and that fatty acid transfer is not specific for palmitate, were initially discovered with viral spike proteins [1,3,36,37]. Since they are synthesized in large amounts and can be purified from virus particles, mass spectrometry was feasible to determine the acyl chains attached to individual cysteines. We found that HA of Influenza B virus contains 97% palmitate attached to two cytoplasmic cysteine residues and HEF of Influenza C virus is predominantly stearoylated at one cysteine at the end of the transmembrane region (Table 1). HAs of Influenza A virus contain a mixture of palmitate and stearate, but stearate is exclusively attached to the cysteine positioned at the end of the transmembrane region, whereas the two cytoplasmic cysteines are acylated with palmitate [38,39]. Shifting the TMR cysteine to a cytoplasmic location virtually eliminated attachment of stearate indicting that the main signal for stearate attachment is the location of an acylation site relative to the transmembrane span [40]. Site-specific attachment of stearate at a transmembrane cysteine was also observed for E1 of togaviruses and F of a paramyxovirus [41]. Whether attachment of palmitate or stearate has functional consequences is not known. However, myristate (C14) and palmitate (C16), which also differ by only two methylene groups show a significant difference in their hydrophobicity, which has a profound effect on the affinity of the acylated peptide for lipids, only palmitate promotes efficient membrane binding [42,43]. In addition, the length of a covalently attached acyl chain might also influence the strength of protein–protein interactions [44].