Potently neutralizing human antibodies that block SARS-CoV-2 receptor binding and protect animals

The COVID-19 pandemic is a major threat to global health for which there are only limited medical countermeasures, and we lack a thorough understanding of mechanisms of humoral immunity1,2. From a panel of monoclonal antibodies (mAbs) targeting the spike (S) glycoprotein isolated from the B cells of infected subjects, we identified several mAbs that exhibited potent neutralizing activity with IC50 values as low as 0.9 or 15 ng/mL in pseudovirus or wild-type (wt) SARS-CoV-2 neutralization tests, respectively. The most potent mAbs fully block the receptor-binding domain of S (SRBD) from interacting with human ACE2. Competition-binding, structural, and functional studies allowed clustering of the mAbs into defined classes recognizing distinct epitopes within major antigenic sites on the SRBD. Electron microscopy studies revealed that these mAbs recognize distinct conformational states of trimeric S protein. Potent neutralizing mAbs recognizing unique sites, COV2-2196 and COV2-2130, bound simultaneously to S and synergistically neutralized authentic SARS-CoV-2 virus. In two murine models of SARS-CoV-2 infection, passive transfer of either COV2-2916 or COV2-2130 alone or a combination of both mAbs protected mice from severe weight loss and reduced viral burden and inflammation in the lung. These results identify protective epitopes on the SRBD and provide a structure-based framework for rational vaccine design and the selection of robust immunotherapeutic cocktails.

Rapid isolation and profiling of a diverse panel of human monoclonal antibodies targeting the SARS-CoV-2 spike protein

Antibodies are a principal determinant of immunity for most RNA viruses and have promise to reduce infection or disease during major epidemics. The novel coronavirus SARS-CoV-2 has caused a global pandemic with millions of infections and hundreds of thousands of deaths to date1,2. In response, we used a rapid antibody discovery platform to isolate hundreds of human monoclonal antibodies (mAbs) against the SARS-CoV-2 spike (S) protein. We stratify these mAbs into five major classes based on their reactivity to subdomains of S protein as well as their cross-reactivity to SARS-CoV. Many of these mAbs inhibit infection of authentic SARS-CoV-2 virus, with most neutralizing mAbs recognizing the receptor-binding domain (RBD) of S. This work defines sites of vulnerability on SARS-CoV-2 S and demonstrates the speed and robustness of new antibody discovery methodologies.

Do innovative immersive virtual reality simulation videos have a role to play in teaching non-technical skills and increasing preparedness for clinical placements for medical students?

This article was migrated. The article was marked as recommended. BACKGROUND:  Teaching non-technical skills (NTS) is an important part of the undergraduate medical curriculum. Resource intensive high-fidelity simulation has an established role in this. Alternative methods of delivering large scale simulation-based education should be considered to help further improve NTS and preparedness for clinical placements of medical students. Emerging technologies such as immersive virtual reality (VR) may have a role in this. AIM:  To assess if a VR simulation-based teaching programme enhances understanding of NTS and preparedness for clinical placements in medical students at the University of Liverpool. METHODS:  A VR simulation-based teaching programme, consisting of 4 sessions of lecture-based simulation and a hi-fidelity simulation session was delivered to 3 rd year medical students. The lecture-based sessions used pre-recorded, immersive clinical scenarios developed by the School of Medicine, with a focus on NTS. The hi-fidelity simulation session was delivered by local hospital trusts. A survey was sent to all students to assess their understanding of key NTS: decision making, task prioritisation and delegation and how the clinical environment works. Preparedness for clinical placement and confidence in the clinical environment was also assessed. A focus group further explored how students felt towards these NTS, with subsequent thematic analysis.  Results: 101/281 students responded to the survey reporting a greater understanding in all NTS assessed. Students also described feeling better prepared for clinical placements. The focus group reported the programme provided a 'safe space' for learning alongside increasing understanding of role modelling and self-awareness.  Discussion: Utilising emerging technology alongside hi-fidelity simulation increased students' exposure to the clinical environment and enabled exploration of NTS by students. Additional work with larger focus groups will be required to further validate our results. Whilst restrictions are limiting clinical exposure due to the COVID-19 pandemic, we propose that VR simulation-based teaching programmes could provide an alternativeeducational tool.

A clinical audit of the electronic data capture of dementia in ambulance service patient records.

BACKGROUND: Dementia is a common diagnosis in older people. It is important to identify and record dementia on emergency call-outs, as it impacts on subsequent care decisions. Ambulance services are changing from paper to electronic patient records, but there are limited data on how frequently and in which sections of the electronic patient record dementia is being recorded. AIMS: To audit the proportion of ambulance electronic patient records where dementia is recorded for patients aged (i) 65 and above and (ii) 75 and above, and to describe the sections in the electronic patient record in which dementia is recorded, as there is currently no standardised button or field available. RESULTS: A total of 314,786 electronic patient records were included in the audit, over a one-year period. The proportion of attended calls with 'dementia' recorded in the electronic patient record in patients aged 65+ was 13.5%, increasing to 16.5% in patients aged 75+, which is similar to that recorded in previous literature. For patients aged 75+ conveyed to hospital, 15.2% had 'dementia' recorded in the electronic patient record, which may indicate under-recording. Recording of dementia between Clinical Commissioning Groups varied between 11.0% and 15.3%. Dementia was recorded in 16 different free-text fields, and 38.4% of records had dementia recorded in more than one field. CONCLUSION: This audit demonstrates high variability in both the frequency of recording dementia and also the location in the electronic patient record. To ensure consistent recording and ease of retrieval to inform patient care and handover, we propose that the electronic patient record should be modified to reflect paramedics' needs, and those of the healthcare staff who receive and act on the report. Enhanced training for paramedics in the importance and method of recording dementia is required. Future data will enable accurate monitoring of trends in conveyance, and inform justifications for alternative services and novel referral pathways.

Using community-based participatory approaches to mobilize communities for policy change.

The Racial and Ethnic Approaches to Community Health (REACH) Alabama Breast and Cervical Cancer Coalition used community-based participatory research principles to address breast and cervical cancer disparities among Alabama's most vulnerable African American communities. With funding from the Centers for Disease Control and Prevention, the Alabama Breast and Cervical Cancer Coalition implemented a multilevel action plan, which entailed disseminating evidence-based strategies to community organizations interested in addressing cancer and other health disparities. Based on the Alabama Breast and Cervical Cancer Coalition's technical assistance on advocacy, an independent, community-led coalition was formed. This article uses a case study approach to document the steps taken by this empowered coalition to mobilize their community to impact cancer disparities using community-based participatory research principles as a tool to change tobacco and breast and cervical cancer legislation.

Wnt10b deficiency promotes coexpression of myogenic and adipogenic programs in myoblasts.

Adult myoblasts retain plasticity in developmental potential and can be induced to undergo myogenic, adipogenic, or osteoblastogenic differentiation in vitro. In this report, we show that the balance between myogenic and adipogenic potential in myoblasts is controlled by Wnt signaling. Furthermore, this balance is altered during aging such that aspects of both differentiation programs are coexpressed in myoblasts due to decreased Wnt10b abundance. Mimicking Wnt signaling in aged myoblasts through inhibition of glycogen synthase kinase or through overexpression of Wnt10b resulted in inhibition of adipogenic gene expression and sustained or enhanced myogenic differentiation. On the other hand, myoblasts isolated from Wnt10b null mice showed increased adipogenic potential, likely contributing to excessive lipid accumulation in actively regenerating myofibers in vivo in Wnt10b-/- mice. Whereas Wnt10b deficiency contributed to increased adipogenic potential in myoblasts, the augmented myogenic differentiation potential observed is likely the result of a compensatory increase in Wnt7b during differentiation of Wnt10b-/- myoblasts. No such compensation was apparent in aged myoblasts and in fact, both Wnt5b and Wnt10b were down-regulated. Thus, alteration in Wnt signaling in myoblasts with age may contribute to impaired muscle regenerative capacity and to increased muscle adiposity, both characteristic of aged muscle.

Alterations in the TGFbeta signaling pathway in myogenic progenitors with age.

Myogenic progenitors in adult muscle are necessary for the repair, maintenance and hypertrophy of post-mitotic muscle fibers. With age, fat deposition and fibrosis contribute to the decline in the integrity and functional capacity of muscles. In a previous study we reported increased accumulation of lipid in myogenic progenitors obtained from aged mice, accompanied by an up-regulation of genes involved in adipogenic differentiation. The present study was designed to extend our understanding of how aging affects the fate and gene expression profile of myogenic progenitors. Affymetrix murine U74 Genechip analysis was performed using RNA extracted from myogenic progenitors isolated from adult (8-month-old) and aged (24-month-old) DBA/2JNIA mice. The cells from the aged animals exhibited major alterations in the expression level of many genes directly or indirectly involved with the TGFbeta signaling pathway. Our data indicate that with age, myogenic progenitors acquire the paradoxical phenotype of being both TGFbeta activated based on overexpression of TGFbeta-inducible genes, but resistant to the differentiation-inhibiting effects of exogenous TGFbeta. The overexpression of TGFbeta-regulated genes, such as connective tissue growth factor, may play a role in increasing fibrosis in aging muscle.

p130/p107 expression distinguishes adipogenic potential in primary myoblasts based on age.

Recent investigations have provided significant evidence that many mesodermally derived tissues contain stem cell-like precursors capable of being stimulated to undergo differentiation into a variety of cellular lineages. We have recently reported that primary myoblasts isolated from 23-month-old mice have an increased adipogenic potential when compared to their 8-month-old counterparts. To further characterize the degree of adipocyte differentiation in these myoblasts, we examined early and late markers of adipocyte differentiation. Within the first 24h of adipocyte differentiation, expression of p130 and p107, two members of the retinoblastoma tumor suppressor gene family, are regulated and this event is an important one early in adipogenesis. Consistent with the increased adipogenic potential of the older myoblasts and in contrast to the younger cells, the p130:p107 pattern of expression is very similar to that observed in adipogenesis where there is a transient increase in p107 expression accompanied by a decrease in p130 expression. Interestingly, while these older cells accumulated lipid and expressed genes associated with lipid metabolism, they failed to express adipsin and leptin, two well-established markers of terminal adipocyte differentiation. These results suggest that older myoblasts are capable of initiating and progressing through the adipogenic program to a point where they express genes associated with lipid metabolism, but do not reach a terminally differentiated state. This finding may have important metabolic implications in the aging population.

Activation of an adipogenic program in adult myoblasts with age.

Myoblasts isolated from mouse hindlimb skeletal muscle demonstrated increased adipogenic potential as a function of age. Whereas myoblasts from 8-month-old adult mice did not significantly accumulate terminal markers of adipogenesis regardless of culture conditions, myoblasts from 23-month-old mice accumulated fat and expressed genes characteristic of differentiated adipocytes, such as the fatty acid binding protein aP2. This change in differentiation potential was associated with a change in the abundance of the mRNA encoding the transcription factor C/EBPalpha, and in the relative abundance of PPARgamma2 to PPARgamma1 mRNAs. Furthermore, PPARgamma activity appeared to be regulated at the level of phosphorylation, being more highly phosphorylated in myoblasts isolated from younger animals. Although adipogenic gene expression in myoblasts from aged animals was activated, presumably in response to PPARgamma and C/EBPalpha, unexpectedly, myogenic gene expression was not effectively repressed. The Wnt signaling pathway may also alter differentiation potential in muscle with age. Wnt-10b mRNA was more abundantly expressed in muscle tissue and cultured myoblasts from adult compared with aged mice, resulting in stabilization of cytosolic beta-catenin, that may potentially contribute to inhibition of adipogenic gene expression in adult myoblasts. The changes reported here, together with those reported in bone marrow stroma with age, suggest that a default program may be activated in mesenchymal cells with increasing age resulting in a more adipogenic-like phenotype. Whether this change in differentiation potential contributes to the increased adiposity in muscle with age remains to be determined.

Molecular characteristics of aged muscle reflect an altered ability to respond to exercise.

Studies have been performed in humans to identify changes in gene expression that may account for the relatively weak and variable response of aged muscle to resistance exercise. The gene expression profile of skeletal muscle from elderly (62-75 years old) compared to younger (20-30 years old) men demonstrated elevated expression of genes typical of a stress or damage response. The expression of the majority of these genes was unaffected by a single bout of high-intensity resistance exercise in elderly subjects but was altered acutely by exercise in younger subjects so as to approach the pre-exercise levels observed in older subjects. The inability of muscle from elderly subjects to respond to resistance exercise was also apparent in the expression of inflammatory response genes, which increased within 24 hours of the exercise bout only in younger subjects. Othergenes with potentially important roles in the adaptation of muscle to exercise, showed a similar or even more robust response in older compared to younger subjects. Taken together, these results may help to explain the variable hypertrophic response of muscle from older individuals to resistance training.

Aged human muscle demonstrates an altered gene expression profile consistent with an impaired response to exercise.

The gene expression profile of skeletal muscle from healthy older (62-75 years old) compared with younger (20-34 years old) men demonstrated elevated expression of genes typical of a stress or damage response, and decreased expression of a gene encoding a DNA repair/cell cycle checkpoint protein. Although the expression of these genes was relatively unaffected by a single bout of resistance exercise in older men, acute exercise altered gene expression in younger men such that post-exercise gene expression in younger men was similar to baseline gene expression in older men. The lack of response of muscle from older subjects to resistance exercise was also apparent in the expression of the inflammatory response gene IL-1beta, which did not differ between the age groups at baseline, but increased within 24 h of the exercise bout only in younger subjects. Other genes with potentially important roles in the adaptation of muscle to exercise, specifically in the processes of angiogenesis and cell proliferation, showed a similar response to exercise in older compared with younger subjects. Only one gene encoding the multifunctional, early growth response transcription factor EGR-1, showed an opposite pattern of expression in response to exercise, acutely decreasing in younger and increasing in older subjects. These results may provide a molecular basis for the inherent variability in the response of muscle from older as compared with younger individuals to resistance training.