The CR3022 antibody, selected from a group of SARS-CoV monoclonal antibodies for its ability to cross-react with SARS-CoV-2, has been examined for its ability to bind to the ectodomain of the ...SARS-CoV-2 spike glycoprotein. Using cryo-electron microscopy we show that antibody binding requires rearrangements in the S1 domain that result in dissociation of the spike.
Recently emerged variants of SARS-CoV-2 contain in their surface spike glycoproteins multiple substitutions associated with increased transmission and resistance to neutralising antibodies. We have ...examined the structure and receptor binding properties of spike proteins from the B.1.1.7 (Alpha) and B.1.351 (Beta) variants to better understand the evolution of the virus in humans. Spikes of both variants have the same mutation, N501Y, in the receptor-binding domains. This substitution confers tighter ACE2 binding, dependent on the common earlier substitution, D614G. Each variant spike has acquired other key changes in structure that likely impact virus pathogenesis. The spike from the Alpha variant is more stable against disruption upon binding ACE2 receptor than all other spikes studied. This feature is linked to the acquisition of a more basic substitution at the S1-S2 furin site (also observed for the variants of concern Delta, Kappa, and Omicron) which allows for near-complete cleavage. In the Beta variant spike, the presence of a new substitution, K417N (also observed in the Omicron variant), in combination with the D614G, stabilises a more open spike trimer, a conformation required for receptor binding. Our observations suggest ways these viruses have evolved to achieve greater transmissibility in humans.
Several variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have emerged during the current coronavirus disease 2019 (COVID-19) pandemic. Although antibody cross-reactivity with ...the spike glycoproteins (S) of diverse coronaviruses, including endemic common cold coronaviruses (HCoVs), has been documented, it remains unclear whether such antibody responses, typically targeting the conserved S2 subunit, contribute to protection when induced by infection or through vaccination. Using a mouse model, we found that prior HCoV-OC43 S-targeted immunity primes neutralizing antibody responses to otherwise subimmunogenic SARS-CoV-2 S exposure and promotes S2-targeting antibody responses. Moreover, vaccination with SARS-CoV-2 S2 elicited antibodies in mice that neutralized diverse animal and human alphacoronaviruses and betacoronaviruses in vitro and provided a degree of protection against SARS-CoV-2 challenge in vivo. Last, in mice with a history of SARS-CoV-2 Wuhan-based S vaccination, further S2 vaccination induced broader neutralizing antibody response than booster Wuhan S vaccination, suggesting that it may prevent repertoire focusing caused by repeated homologous vaccination. These data establish the protective value of an S2-targeting vaccine and support the notion that S2 vaccination may better prepare the immune system to respond to the changing nature of the S1 subunit in SARS-CoV-2 variants of concern, as well as to future coronavirus zoonoses.
The degree of heterotypic immunity induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strains is a major determinant of the spread of emerging variants and the success of ...vaccination campaigns, but remains incompletely understood. We examined the immunogenicity of SARS-CoV-2 variant B.1.1.7 (Alpha) that arose in the United Kingdom and spread globally. We determined titres of spike glycoprotein-binding antibodies and authentic virus neutralising antibodies induced by B.1.1.7 infection to infer homotypic and heterotypic immunity. Antibodies elicited by B.1.1.7 infection exhibited significantly reduced recognition and neutralisation of parental strains or of the South Africa variant B.1.351 (Beta) than of the infecting variant. The drop in cross-reactivity was significantly more pronounced following B.1.1.7 than parental strain infection. The results indicate that heterotypic immunity induced by SARS-CoV-2 variants is asymmetric.
Modern and effective patient care requires specialist healthcare professionals working together. Interprofessional learning (IPL) seeks to provide opportunities for different healthcare disciplines ...to learn with, from and about each other. This study focused on the delivery and evaluation of a cytomegalovirus (CMV) case study workshop to facilitate IPL between two Health and Care Professions Council (HCPC) regulated courses: Biomedical Science and Audiology. The 2 h online workshop consisted of 1) defining the roles, responsibilities and skills of the two healthcare professions, 2) the structure of the Biomedical Science and Audiology departments, 3) routes to HCPC registration, 4) core curriculum of both degree programmes and 5) interpreting interdisciplinary data related to a CMV patient case. The workshop was interactive, with the virtual learning environment promoting peer discussions and the use of online polling. Student responses were collected through an online questionnaire. A total of 108 respondents completed a post-event survey and Mann-Whitney
tests revealed there were no significant differences in the responses between the two student cohorts in response to each of the survey statements (
> 0.05). A total of 82.4% of students agreed that they need to know the role of other healthcare professionals for their future practice, whilst 84.2% agreed that the CMV case study was a good format to facilitate effective IPL. A total of 93.5% of respondents recognised the importance of both professions in diagnosing a patient with CMV. Thematic analysis identified four common themes, including appreciation of shared roles, recognition of similarities in registration pathways, working together to provide holistic patient care and the role of clinicians in the patient journey. This novel collaboration between Biomedical Science and Audiology facilitated effective IPL whilst meeting the interprofessional education HCPC requirements. Collaborative working is an essential component of delivering effective patient care and allied healthcare degrees need to provide opportunities within their curriculum to foster this. We hope this study encourages other higher education institutes to expand and develop their current IPL activities to include a broader spectrum of healthcare courses.
Serological and plasmablast responses and plasmablast-derived IgG monoclonal antibodies (MAbs) have been analysed in three COVID-19 patients with different clinical severities. Potent humoral ...responses were detected within 3 weeks of onset of illness in all patients and the serological titre was elicited soon after or concomitantly with peripheral plasmablast response. An average of 13.7% and 3.5% of plasmablast-derived MAbs were reactive with virus spike glycoprotein or nucleocapsid, respectively. A subset of anti-spike (10 of 32) antibodies cross-reacted with other betacoronaviruses tested and harboured extensive somatic mutations, indicative of an expansion of memory B cells upon SARS-CoV-2 infection. Fourteen of 32 anti-spike MAbs, including five anti-receptor-binding domain (RBD), three anti-non-RBD S1 and six anti-S2, neutralised wild-type SARS-CoV-2 in independent assays. Anti-RBD MAbs were further grouped into four cross-inhibiting clusters, of which six antibodies from three separate clusters blocked the binding of RBD to ACE2 and five were neutralising. All ACE2-blocking anti-RBD antibodies were isolated from two recovered patients with prolonged fever, which is compatible with substantial ACE2-blocking response in their sera. Finally, the identification of non-competing pairs of neutralising antibodies would offer potential templates for the development of prophylactic and therapeutic agents against SARS-CoV-2.
In 2014, the Centre for Health Protection in Hong Kong introduced screening for influenza C virus (ICV) as part of its routine surveillance for infectious agents in specimens collected from patients ...presenting with symptoms of respiratory viral infection, including influenza-like illness (ILI). A retrospective analysis of ICV detections up to week 26 of 2019 revealed persistent low-level circulation, with two outbreaks having occurred in the winters of 2015 to 2016 and 2017 to 2018. These outbreaks occurred at the same time as, and were dwarfed by, seasonal epidemics of influenza types A and B. Gene sequencing studies on stored ICV-positive clinical specimens from the two outbreaks have shown that the hemagglutinin-esterase (HE) genes of the viruses fall into two of the six recognized genetic lineages (represented by C/Kanagawa/1/76 and C/São Paulo/378/82), with there being significant genetic drift compared to earlier circulating viruses within both lineages. The location of a number of encoded amino acid substitutions in hemagglutinin-esterase fusion (HEF) glycoproteins suggests that antigenic drift may also have occurred. Observations of ICV outbreaks in other countries, with some of the infections being associated with severe disease, indicates that ICV infection has the potential to have significant clinical and health care impacts in humans.
Influenza C virus infection of humans is common, and reinfection can occur throughout life. While symptoms are generally mild, severe disease cases have been reported, but knowledge of the virus is limited, as little systematic surveillance for influenza C virus is conducted and the virus cannot be studied by classical virologic methods because it cannot be readily isolated in laboratories. A combination of systematic surveillance in Hong Kong SAR, China, and new gene sequencing methods has been used in this study to assess influenza C virus evolution and provides evidence for a 2-year cycle of disease outbreaks. The results of studies like that reported here are key to developing an understanding of the impact of influenza C virus infection in humans and how virus evolution might be associated with epidemics.
Valorization of vegetable oil waste residues is gaining importance due to their high protein and polyphenol contents. Protease inhibitors (PIs), proteins from these abundantly available waste ...residues, have recently gained importance in treating chronic diseases. This research aimed to use canola meal of genetically diverse
genotypes, BLN-3347 and Rivette, to identify PIs with diverse functionalities in therapeutic and pharmacological applications. The canola meal PI purification steps involved: native PAGE and trypsin inhibition activity, followed by ammonium sulfate fractionation, anion exchange, gel filtration, and reverse-phase chromatography. The purified PI preparations were characterized using SDS-PAGE, isoelectric focusing (IEF), and N terminal sequencing. SDS-PAGE analysis of PI preparations under native reducing and nonreducing conditions revealed three polymorphic PIs in each genotype. The corresponding IEF of the genotype BLN-3347, exhibited three acidic isoforms with isoelectric points (p
) of 4.6, 4.0, and 3.9, while Rivette possessed three isoforms, exhibiting two basic forms of p
8.65 and 9.9, and one acidic of p
6.55. Purified PI preparations from both the genotypes displayed dipeptidyl peptidase-IV (DPP-IV) and angiotensin-converting enzyme (ACE) inhibition activities; the BLN-3347 PI preparation exhibited a strong inhibitory effect with lower IC
values (DPP-IV 37.42 µg/mL; ACE 129 µg/mL) than that from Rivette (DPP-IV 67.97 µg/mL; ACE 376.2 µg/mL). In addition to potential human therapy, these highly polymorphic PIs, which can inhibit damaging serine proteases secreted by canola plant pathogens, have the potential to be used by canola plant breeders to seek qualitative trait locus (QTLs) linked to genes conferring resistance to canola diseases.
IntroductionHearing loss is a common chronic health condition and adversely affects communication and social function resulting in loneliness, social isolation and depression. We know little about ...the patient experience of living with hearing loss and their views on the quality of the audiology service. In this study, we will develop and validate the first patient-reported experience measure (PREM) to understand patients’ experiences of living with hearing loss and their healthcare interactions with audiology services.Methods and analysisWe will develop the PREM in three phases: (1) development of PREM prototype (items/statements) derived from previous qualitative work and narrative review, (2) cognitive interview testing of the PREM prototype using a ‘think aloud’ technique to examine the acceptability and comprehensibility of the tool and refine accordingly and (3) psychometric testing of the modified PREM with 300 participants to assess the reliability and validity of the tool using Rasch analyses with sequential item reduction. Eligible participants will be young people and adults aged 16 years and over who have hearing loss. Participants will be recruited from three clinical sites located in England (Bath, Bristol) and Scotland (Tayside) and non-clinical settings (eg, lip-reading classes, residential care settings, national charity links, social media).Ethics and disseminationThe study was approved by the West of Scotland Research Ethics Service (approval date: 6 May 2022; ref: 22/WS/0057) and the Health Research Authority and Health and Care Research Wales (HCRW) Approval (approval date: 14 June 2022; IRAS project ID: 308816). Findings will be shared with our patient and public involvement groups, academics, audiology communities and services and local commissioners via publications and presentations. The PREM will be made available to clinicians and researchers without charge.
The PA-X protein of influenza A virus has roles in host cell shutoff and viral pathogenesis. While most strains are predicted to encode PA-X, strain-dependent variations in activity have been noted. ...We found that PA-X protein from the A/PR/8/34 (PR8) strain had significantly lower repressive activity against cellular gene expression than PA-X proteins from the avian strains A/turkey/England/50-92/91 (H5N1) (T/E) and A/chicken/Rostock/34 (H7N1). Loss of normal PA-X expression, either by mutation of the frameshift site or by truncating the X open reading frame (ORF), had little effect on the infectious virus titer of PR8 or PR8 7:1 reassortants with T/E segment 3 grown in embryonated hens' eggs. However, in both virus backgrounds, mutation of PA-X led to decreased embryo mortality and lower overall pathology, effects that were more pronounced in the PR8 strain than in the T/E reassortant, despite the low shutoff activity of the PR8 PA-X. Purified PA-X mutant virus particles displayed an increased ratio of hemagglutinin (HA) to nucleoprotein (NP) and M1 compared to values for their wild-type (WT) counterparts, suggesting altered virion composition. When the PA-X gene was mutated in the background of poorly growing PR8 6:2 vaccine reassortant analogues containing the HA and neuraminidase (NA) segments from H1N1 2009 pandemic viruses or from an avian H7N3 strain, HA yield increased up to 2-fold. This suggests that the PR8 PA-X protein may harbor a function unrelated to host cell shutoff and that disruption of the PA-X gene has the potential to improve the HA yield of vaccine viruses.
Influenza A virus is a widespread pathogen that affects both humans and a variety of animal species, causing regular epidemics and sporadic pandemics, with major public health and economic consequences. A better understanding of virus biology is therefore important. The primary control measure is vaccination, which for humans mostly relies on antigens produced in eggs from PR8-based viruses bearing the glycoprotein genes of interest. However, not all reassortants replicate well enough to supply sufficient virus antigen for demand. The significance of our research lies in identifying that mutation of the PA-X gene in the PR8 strain of virus can improve antigen yield, potentially by decreasing the pathogenicity of the virus in embryonated eggs.
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