Dissecting strategies to tune the therapeutic potential of SARS-CoV-2-specific monoclonal antibody CR3022

The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), coupled with a lack of therapeutics, has paralyzed the globe. Although significant effort has been invested in identifying antibodies that block infection, the ability of antibodies to target infected cells through Fc interactions may be vital to eliminate the virus. To explore the role of Fc activity in SARS-CoV-2 immunity, the functional potential of a cross–SARS-reactive antibody, CR3022, was assessed. CR3022 was able to broadly drive antibody effector functions, providing critical immune clearance at entry and upon egress. Using selectively engineered Fc variants, no protection was observed after administration of WT IgG1 in mice or hamsters. Conversely, the functionally enhanced Fc variant resulted in increased pathology in both the mouse and hamster models, causing weight loss in mice and enhanced viral replication and weight loss in the more susceptible hamster model, highlighting the pathological functions of Fc-enhancing mutations. These data point to the critical need for strategic Fc engineering for the treatment of SARS-CoV-2 infection.

Rapid and complete inactivation of SARS-CoV-2 by ultraviolet-C irradiation

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has devastated global public health systems and economies, with over 52 million people infected, millions of jobs and businesses lost, and more than 1 million deaths recorded to date. Contact with surfaces contaminated with droplets generated by infected persons through exhaling, talking, coughing and sneezing is a major driver of SARS-CoV-2 transmission, with the virus being able to survive on surfaces for extended periods of time. To interrupt these chains of transmission, there is an urgent need for devices that can be deployed to inactivate the virus on both recently and existing contaminated surfaces. Here, we describe the inactivation of SARS-CoV-2 in both wet and dry format using radiation generated by a commercially available Signify ultraviolet (UV)-C light source at 254 nm. We show that for contaminated surfaces, only seconds of exposure is required for complete inactivation, allowing for easy implementation in decontamination workflows.

2020 taxonomic update for phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales

In March 2020, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. At the genus rank, 20 new genera were added, two were deleted, one was moved, and three were renamed. At the species rank, 160 species were added, four were deleted, ten were moved and renamed, and 30 species were renamed. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.

Molecular basis for a germline-biased neutralizing antibody response to SARS-CoV-2

The SARS-CoV-2 viral spike (S) protein mediates attachment and entry into host cells and is a major target of vaccine and drug design. Potent SARS-CoV-2 neutralizing antibodies derived from closely related antibody heavy chain genes (IGHV3-53 or 3-66) have been isolated from multiple COVID-19 convalescent individuals. These usually contain minimal somatic mutations and bind the S receptor-binding domain (RBD) to interfere with attachment to the cellular receptor angiotensin-converting enzyme 2 (ACE2). We used antigen-specific single B cell sorting to isolate S-reactive monoclonal antibodies from the blood of a COVID-19 convalescent individual. The seven most potent neutralizing antibodies were somatic variants of the same IGHV3-53-derived antibody and bind the RBD with varying affinity. We report X-ray crystal structures of four Fab variants bound to the RBD and use the structures to explain the basis for changes in RBD affinity. We show that a germline revertant antibody binds tightly to the SARS-CoV-2 RBD and neutralizes virus, and that gains in affinity for the RBD do not necessarily correlate with increased neutralization potency, suggesting that somatic mutation is not required to exert robust antiviral effect. Our studies clarify the molecular basis for a heavily germline-biased human antibody response to SARS-CoV-2.

A trimeric human angiotensin-converting enzyme 2 as an anti-SARS-CoV-2 agent in vitro

Effective intervention strategies are urgently needed to control the COVID-19 pandemic. Human angiotensin-converting enzyme 2 (ACE2) is a carboxypeptidase that forms a dimer and serves as the cellular receptor for SARS-CoV-2. It is also a key negative regulator of the renin-angiotensin system (RAS), conserved in mammals, which modulates vascular functions. We report here the properties of a trimeric ACE2 variant, created by a structure-based approach, with binding affinity of ~60 pM for the spike (S) protein of SARS-CoV-2, while preserving the wildtype peptidase activity as well as the ability to block activation of angiotensin II receptor type 1 in the RAS. Moreover, the engineered ACE2 potently inhibits infection of SARS-CoV-2 in cell culture. These results suggest that engineered, trimeric ACE2 may be a promising anti-SARS-CoV-2 agent for treating COVID-19.

Cellular Nanosponges Inhibit SARS-CoV-2 Infectivity

We report cellular nanosponges as an effective medical countermeasure to the SARS-CoV-2 virus. Two types of cellular nanosponges are made of the plasma membranes derived from human lung epithelial type II cells or human macrophages. These nanosponges display the same protein receptors, both identified and unidentified, required by SARS-CoV-2 for cellular entry. It is shown that, following incubation with the nanosponges, SARS-CoV-2 is neutralized and unable to infect cells. Crucially, the nanosponge platform is agnostic to viral mutations and potentially viral species, as well. As long as the target of the virus remains the identified host cell, the nanosponges will be able to neutralize the virus.

Cellular Nanosponges Inhibit SARS-CoV-2 Infectivity

We report cellular nanosponges as an effective medical countermeasure to the SARS-CoV-2 virus. Two types of cellular nanosponges are made of the plasma membranes derived from human lung epithelial type II cells or human macrophages. These nanosponges display the same protein receptors, both identified and unidentified, required by SARS-CoV-2 for cellular entry. It is shown that, following incubation with the nanosponges, SARS-CoV-2 is neutralized and unable to infect cells. Crucially, the nanosponge platform is agnostic to viral mutations and potentially viral species, as well. As long as the target of the virus remains the identified host cell, the nanosponges will be able to neutralize the virus.

Reaudit of transvaginal ultrasound practice in a general gynecology clinic

PURPOSE

A recent pilot audit found that the quality of transvaginal ultrasound practice in a teaching hospital did not reflect current guidelines. This was a concern given the frequency and importance of ultrasound examinations in approaching a diagnosis. Interventional measures involved ad hoc training sessions coincident with installation of updated equipment. A reaudit was performed to assess any changes in the standard of ultrasound practice.

METHODS

Data were collected by random direct observation. To minimize the Hawthorne effect, staffs were not made aware of when active data collection took place. Observations of both patients and end user were compared with current guidelines. Data collected maintained the anonymity of users throughout. Practice was graded as: compliant, partially-compliant, or noncompliant. Descriptive statistics were used to demonstrate any change post-intervention.

RESULTS

Observations (n = 48) of completed gynecology ultrasound practice were recorded, and results described as percentage frequencies (%). Image optimization noncompliant rates declined in the reaudit from 65.1% to 41.67% (P = .07) and noncompliant rates of global examination of gynecology decreased from 60.47% to 14.58% (P < .05). Substantial improvements were seen in terms of image annotations (initial audit, 41.9% vs reaudit, 66.67%), and end user examination of bladder, vagina and cervix when indicated (initial audit, 25.6% vs reaudit, 77.08%).

CONCLUSION

Regular audit, ad hoc ultrasound training sessions and updated ultrasound equipment resulted in considerably improved compliance of transvaginal ultrasound practice in gynecology.

Endometriosis in a case with Fraser Syndrome

Introduction:

Fraser Syndrome is a rare genetic disorder characterized by urogenital defects, cutaneous syndactyly and cryptophthalmos commonly diagnosed during foetal autopsy. Vaginal atresia is one of the major diagnostic criteria of Fraser Syndrome and could be a contributing factor of endometriosis following the development of hematocolpos. Imperforate hymen, often misdiagnosed as vaginal atresia, is a rare diagnosis in patients with Müllerian anomalies. Here, we report a case of Fraser Syndrome with chronic pelvic pain as a result of delayed hymenotomy and the extensive management of endometriosis.

Case Report:

A 15-year-old girl with Fraser Syndrome presented with pelvic pain. Examination revealed a large hematocolpos caused by an imperforate hymen. Due to the lack of paediatric intensive care locally, she had a delayed hymenotomy. She continued to suffer from chronic pelvic non-cyclical pain post-hymenotomy. Preliminary laparoscopy and biopsy showed endometriosis. Despite excision and clearance of endometriosis, she experienced persistent pain while taking morphine and was trialled with several hormonal therapies such as leuprorelin acetate, progestogen and combined hormonal therapy. She received medical therapy for 10 years until she re-presented with erratic bleeding and pain. Laparoscopy again identified endometriosis.

Conclusion:

Early recognition and treatment minimize risk of endometriosis especially in premenarcheal adolescent girls with obstructive Müllerian anomalies presenting with pelvic pain. Adequate pain control and medical management permit a delay in surgical intervention facilitating further investigations and thorough counselling with the patient and family about the implications of endometriosis on fertility and quality of life.

Bivalent Junin & Machupo experimental vaccine based on alphavirus RNA replicon vector

Junin (JUNV) and Machupo (MACV), two mammalian arenaviruses placed on the 2018 WHO watch list, are prevalent in South America causing Argentine and Bolivian hemorrhagic fevers (AHF and BHF), respectively. The live attenuated JUNV vaccine, Candid #1, significantly reduced the incidence of AHF. Vaccination induces neutralizing antibody (nAb) responses which effectively target GP1 (the viral attachment glycoprotein) pocket which accepts the tyrosine residue of the cellular receptor, human transferrin receptor 1 (TfR1). In spite of close genetic relationships between JUNV and MACV, variability in the GP1 receptor binding site (e.g., MACV GP1 loop 10) results in poor MACV neutralization by Candid #1-induced nAbs. Candid #1 is not recommended for vaccination of children younger than 15 years old (a growing "at risk" group), pregnant women, or other immunocompromised individuals. Candid #1's primary reliance on limited missense mutations for attenuation, genetic heterogeneity, and potential stability concerns complicate approval of this vaccine in the US. To address these issues, we applied alphavirus RNA replicon vector technology based on the human Venezuelan equine encephalitis vaccine (VEEV) TC-83 to generate replication restricted virus-like-particles vectors (VLPVs) simultaneously expressing cellular glycoprotein precursors (GPC) of both viruses, JUNV and MACV. Resulting JV&MV VLPVs were found safe and immunogenic in guinea pigs. Immunization with VLPVs induced humoral responses which correlated with complete protection against lethal disease after challenge with pathogenic strains of JUNV (Romero) and MACV (Carvallo).

A26 PEDIATRIC-ONSET INFLAMMATORY BOWEL DISEASE INCREASES THE RISK OF VENOUS THROMBOEMBOLISM: A CANGIEC POPULATION-BASED STUDY

Background

Inflammatory bowel disease (IBD) increases the risk of venous thromboembolism (VTE) in patients of all ages but the risk of VTE among Canadian children with IBD has not previously been investigated.

Aims

Report the incidence of VTE and subtypes pulmonary embolism (PE) and deep vein thrombosis (DVT) in children with and without IBD.

Methods

Children diagnosed with IBD &lt;16y were identified from health administrative data in Ontario (2002–2014), Alberta (2007–2015), and Nova Scotia (2002–2012) using validated algorithms and matched by age and sex to children without IBD (1:5 ratio). Validated ICD-10 codes identified hospitalizations for incident VTE (DVT, PE, and sinovenous thrombosis). Province-specific 5-year cumulative incidence per 1000 person-years (PY) of VTEs were pooled using fixed-effects generalized linear mixed models with a Freeman-Tukey double arcsine transformation. Incidence rate ratios (IRR) within 5 years of diagnosis were pooled using fixed-effects generalized linear mixed models to compare children with and without IBD, and children with Crohn’s disease (CD) and ulcerative colitis (UC).

Results

3127 children with IBD (1826 CD; 1045 UC) were matched to 15,635 children without IBD. The cumulative incidence of VTE within 5 years of IBD diagnosis was 2.8 (95% CI 2.1–3.8) per 1000 PYs compared to 0.13 (95% CI 0.07–0.24) per 1000 PYs in children without IBD (Table). The 5-year cumulative incidences of VTE, DVT, and PE were significantly higher in children with IBD than in children without IBD (VTE: IRR 21.44, 95% CI 10.73–42.82; DVT: IRR 25.15, 95% CI 11.12–56.89; PE: IRR 4.01, 95% CI 1.22–13.18). Compared to UC patients, children with CD were at lower risk of VTE (IRR 0.53, 95% CI 0.29–0.96) and numerically, but not statistically, lower risk of DVT (IRR 0.59, 95% CI 0.30–1.14).

Conclusions

Although VTEs are relatively rare among children with IBD, these children are at much greater risk than children without IBD. Gastroenterologists caring for these patients should be cognizant of VTE risk and provide appropriate prophylaxis to those at high risk of VTE.

Funding Agencies

CCC

A228 EVOLUTION OF MRE FINDINGS IN PAEDIATRIC PATIENTS WITH SMALL BOWEL CROHN’S DISEASE ON MAINTENANCE METHOTREXATE

Background

Observational data in children and RCT data in adults indicate that methotrexate (MTX) is associated with induction and maintenance of clinical remission in luminal Crohn’s disease, but efficacy in achieving intestinal healing has not been examined.

Aims

To examine the evolution of MRE signs of inflammation in children treated with MTX.

Methods

In this retrospective cohort study, we reviewed paediatric CD patients on maintenance MTX monotherapy for &gt;4 months who underwent serial MREs between July 2010 and October 2015. MREs were reviewed by a radiologist blind to clinical data. Overall inflammatory activity on each MRE was scored as minimal, mild, moderate or severe, informed by the presence of bowel wall thickness, wall enhancement, T2 hyperintensity, comb sign, mesenteric edema, penetrating disease, stricturing, diffusion restriction and motility. The radiologist’s global assessment of change from MRE 1 to MRE 2 was scored as improved, unchanged or worsened. Clinical findings, disease activity (assessed by weighted paediatric CD activity index [wPCDAI]) and surgical history were also extracted from medical records by a clinician blind to MRE results.

Results

Thirty-five patients were included (median age at diagnosis 12 [IQR 11–14] years; 77% male; 60% inflammatory (B1), 17% stricturing (B2), 23% penetrating (B3) disease). Between baseline and follow-up MRE, wPCDAI (median 15 [IQR 7–43] decreased to 8 [IQR 0–18]; p=0.006) and CRP (median 9 [IQR 2–36] decreased to 5 [IQR 5–9]; p=0.013) and 74% (N=26) were in clinical remission (wPCDAI &lt; 12.5) at MRE 2. MRE features that significantly improved from MRE 1 to 2 were comb sign from 63% (N=37) to 38% (N=14) (p=0.02) and penetrating disease from 14% (N=8) to 0 (p=0.03). After a median of 17 months (IQR 13–23), 51% (N=18) of patients improved, 29% (N=10) worsened and 20% (N=7) had no change based on the radiologist’s global assessment. Of the 21 patients with moderate/severe disease at MRE 1, 33% (N=7) had minimal/mild disease by MRE 2. 66% (N=14/21) continued to have moderate/severe disease at MRE 2. Additionally, a further 14% (N=2/14) of those with minimal/mild disease at baseline MRE progressed to moderate/severe disease at MRE 2. Complete details of change between MRE 1 and MRE 2 are displayed in Figure 1.

Conclusions

Despite signs of clinical improvement, many paediatric CD patients on maintenance MTX therapy for &gt;4 months have unchanged or worsened MRE findings. This underscores the need for follow-up imaging in these cases.

Funding Agencies

None

Ebola virus disease

Ebola virus disease (EVD) is a severe and frequently lethal disease caused by Ebola virus (EBOV). EVD outbreaks typically start from a single case of probable zoonotic transmission, followed by human-to-human transmission via direct contact or contact with infected bodily fluids or contaminated fomites. EVD has a high case-fatality rate; it is characterized by fever, gastrointestinal signs and multiple organ dysfunction syndrome. Diagnosis requires a combination of case definition and laboratory tests, typically real-time reverse transcription PCR to detect viral RNA or rapid diagnostic tests based on immunoassays to detect EBOV antigens. Recent advances in medical countermeasure research resulted in the recent approval of an EBOV-targeted vaccine by European and US regulatory agencies. The results of a randomized clinical trial of investigational therapeutics for EVD demonstrated survival benefits from two monoclonal antibody products targeting the EBOV membrane glycoprotein. New observations emerging from the unprecedented 2013-2016 Western African EVD outbreak (the largest in history) and the ongoing EVD outbreak in the Democratic Republic of the Congo have substantially improved the understanding of EVD and viral persistence in survivors of EVD, resulting in new strategies toward prevention of infection and optimization of clinical management, acute illness outcomes and attendance to the clinical care needs of patients.

A pilot study to evaluate the practice of transvaginal gynecological sonography in a general gynecology clinic

PURPOSE

Ultrasound is the imaging method of choice in gynecology. The quality and diagnostic accuracy of ultrasound depends on the skills of the individual performing the scan. Evaluation of ultrasound practice has received limited attention.

METHODS

A video recording device was connected to an ultrasound machine in gynecology clinics in a teaching hospital. To minimize the observer effect, all staff were notified through email in advance. Data were collected over a 3-week period. Anonymous recordings of both patients and user were compared with current guidelines, and practice was categorized as: compliant, partially compliant, or non-compliant.

RESULTS

Observations (n = 43) were categorized and the results described as percentage frequencies (%). Image optimization was compliant in 23.3% of recorded observations, 11.6% was partially compliant, and 65.1% was noncompliant. The study also found that global examination on gynecology was 20.9% compliant, 18.6% partially compliant, and 60.47% noncompliant. Images were annotated in appropriately 41.9% of instances, and 25.6% of end-users examined bladder, vagina, and cervix when indicated.

CONCLUSION

The pilot evaluation showed that ultrasound practice among end-users did not reflect current guidelines, suggesting a need for improvement. Accuracy and performance of ultrasound examination remains highly operator-dependent although video evaluation can be an effective tool for assessing such skills.

Menopause and work: an overview of UK guidance

Background

Recent evidence suggests that some women experience menopausal symptoms that impact on their working lives, and that work environments can impact upon the experience of menopause. As a result, guidance for employers and other key stakeholders about this potential occupational health issue has emerged. To date there has not been a review of these documents to identify their main recommendations for policy and practice.

Aims

To provide a narrative overview of such guidance and summary of content.

Methods

Documents published in the UK and available in a major UK trade union library were searched systematically to identify guidance on the topic of menopause and work. An inductive thematic analysis was performed to identify the main themes addressed.

Results

Twenty-five relevant documents, on average eight pages long, were identified. A minority indicated that the use of scientific evidence informed the content. Five overarching themes were identified: (i) legislation; (ii) policy; (iii) information and training needs; (iv) workplace support; and (v) the physical work environment.

Conclusions

This overview of UK guidance revealed common areas of concern about reducing and managing difficulties experienced by working menopausal women. Possible areas for action were identified. Some recommendations were common across much of the guidance, whereas others were exclusive. Future guidance might include consideration of all these issues, while making reference both to the evidence base and sources of further information.

Taxonomy of the order Mononegavirales: update 2019

In February 2019, following the annual taxon ratification vote, the order Mononegavirales was amended by the addition of four new subfamilies and 12 new genera and the creation of 28 novel species. This article presents the updated taxonomy of the order Mononegavirales as now accepted by the International Committee on Taxonomy of Viruses (ICTV).

Adaptation of an R5 Simian-Human Immunodeficiency Virus Encoding an HIV Clade A Envelope with or without Ablation of Adaptive Host Immunity: Differential Selection of Viral Mutants

Simian-human immunodeficiency virus (SHIV) infection in rhesus macaques (RMs) resembles human immunodeficiency virus type 1 (HIV-1) infection in humans and serves as a tool to evaluate candidate AIDS vaccines. HIV-1 clade A (HIV-A) predominates in parts of Africa. We constructed an R5 clade A SHIV (SHIV-A; strain SHIV-KNH1144) carrying env from a Kenyan HIV-A. SHIV-A underwent rapid serial passage through six RMs. To allow unbridled replication without adaptive immunity, we simultaneously ablated CD8+ and B cells with cytotoxic monoclonal antibodies in the next RM, resulting in extremely high viremia and CD4+ T-cell loss. Infected blood was then transferred into two non-immune-depleted RMs, where progeny SHIV-A showed increased replicative capacity and caused AIDS. We reisolated SHIV-KNH1144p4, which was replication competent in peripheral blood mononuclear cells (PBMC) of all RMs tested. Next-generation sequencing of early- and late-passage SHIV-A strains identified mutations that arose due to "fitness" virus optimization in the former and mutations exhibiting signatures typical for adaptive host immunity in the latter. "Fitness" mutations are best described as mutations that allow for better fit of the HIV-A Env with SIV-derived virion building blocks or host proteins and mutations in noncoding regions that accelerate virus replication, all of which result in the outgrowth of virus variants in the absence of adaptive T-cell and antibody-mediated host immunity.IMPORTANCE In this study, we constructed a simian-human immunodeficiency virus carrying an R5 Kenyan HIV-1 clade A env (SHIV-A). To bypass host immunity, SHIV-A was rapidly passaged in naive macaques or animals depleted of both CD8+ and B cells. Next-generation sequencing identified different mutations that resulted from optimization of viral replicative fitness either in the absence of adaptive immunity or due to pressure from adaptive immune responses.

Rapid and Fully Microfluidic Ebola Virus Detection with CRISPR-Cas13a

Highly infectious illness caused by pathogens is endemic especially in developing nations where there is limited laboratory infrastructure and trained personnel. Rapid point-of-care (POC) serological assays with minimal sample manipulation and low cost are desired in clinical practice. In this study, we report an automated POC system for Ebola RNA detection with RNA-guided RNA endonuclease Cas13a, utilizing its collateral RNA degradation after its activation. After automated microfluidic mixing and hybridization, nonspecific cleavage products of Cas13a are immediately measured by a custom integrated fluorometer which is small in size and convenient for in-field diagnosis. Within 5 min, a detection limit of 20 pfu/mL (5.45 × 10⁷ copies/mL) of purified Ebola RNA is achieved. This isothermal and fully solution-based diagnostic method is rapid, amplification-free, simple, and sensitive, thus establishing a key technology toward a useful POC diagnostic platform.

ICTV Virus Taxonomy Profile: Filoviridae

Members of the family Filoviridae produce variously shaped, often filamentous, enveloped virions containing linear non-segmented, negative-sense RNA genomes of 15-19 kb. Several filoviruses (e.g., Ebola virus) are pathogenic for humans and are highly virulent. Several filoviruses infect bats (e.g., Marburg virus), whereas the hosts of most other filoviruses are unknown. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on Filoviridae, which is available at www.ictv.global/report/filoviridae.

Managing employees with dementia: a systematic review

BACKGROUND

The experience of developing dementia while in employment has been explored from the point of view of the employee, but less is known about the perspectives, experiences and needs of employers.

AIMS

To review systematically literature about the management of employees who develop dementia whilst in employment.

METHODS

Databases searched included MEDLINE, EMBASE, PsycINFO, CINAHL, BNI, ABI Inform, ISI Web of Science, Open Grey and dementia journals database; 44 documents were identified for inclusion in the review: 22 journal papers, one PhD thesis and 21 articles, reports and webpages from the grey literature. As all documents were qualitative in nature a thematic synthesis of their content was undertaken.

RESULTS

Three main themes and ten sub-themes were identified. The main themes concerned early presentation and identification in the workplace; reasonable adjustments for people with working age dementia; and the provision of information to raise awareness and facilitate informed choice. The evidence suggested that there is a lack of awareness about working age dementia and that this may impact negatively on employees. Guidance for employers offered suggestions for good practice.

CONCLUSIONS

Guidance for employers is increasingly available although it rarely refers to the evidence base. There is a need for future studies that explore the effectiveness of guidance and training initiatives for employers. Examples of good practice where employees with dementia have been well supported in the workplace and who have been able to leave the workforce with dignity, would be helpful.