The Neutralizing Antibody Responses of Individuals That Spontaneously Resolve Hepatitis C Virus Infection

Hepatitis C virus (HCV) infection is a major global health problem. In the majority of cases the virus is not cleared by the host immune response and progresses to chronic infection. Studies of the neutralizing antibody responses in individuals that naturally clear infection are limited. Understanding what constitutes a successful antibody response versus one that has 'failed' and resulted in chronic infection is important to understand what type of antibody response would need to be elicited by a protective vaccine. Samples from spontaneous clearers are difficult to obtain therefore studies are often limited. In our study through HCV Research UK, we had access to a cohort of over 200 samples. We identified the samples that contained HCV neutralizing antibodies using ELISA and HCV pseudoparticle (HCVpp) assays. We then utilised mutagenesis and cross-competition analysis to determine the profile of the neutralizing antibody responses. In addition, we analysed a cohort of samples from chronic infection using the same techniques to enable direct comparison of the antibody profiles observed in both cohorts. We conclude that similar profiles are present in both cohorts indicating that it is not the neutralizing antibody response per se that determines the outcome of infection. These data will provide useful information for future HCV vaccine design.

An Antigenically Diverse, Representative Panel of Envelope Glycoproteins for Hepatitis C Virus Vaccine Development

BACKGROUND & AIMS

Development of a prophylactic hepatitis C virus (HCV) vaccine will require accurate and reproducible measurement of neutralizing breadth of vaccine-induced antibodies. Currently available HCV panels may not adequately represent the genetic and antigenic diversity of circulating HCV strains, and the lack of standardization of these panels makes it difficult to compare neutralization results obtained in different studies. Here, we describe the selection and validation of a genetically and antigenically diverse reference panel of 15 HCV pseudoparticles (HCVpps) for neutralization assays.

METHODS

We chose 75 envelope (E1E2) clones to maximize representation of natural polymorphisms observed in circulating HCV isolates, and 65 of these clones generated functional HCVpps. Neutralization sensitivity of these HCVpps varied widely. HCVpps clustered into 15 distinct groups based on patterns of relative sensitivity to 7 broadly neutralizing monoclonal antibodies. We used these data to select a final panel of 15 antigenically representative HCVpps.

RESULTS

Both the 65 and 15 HCVpp panels span 4 tiers of neutralization sensitivity, and neutralizing breadth measurements for 7 broadly neutralizing monoclonal antibodies were nearly equivalent using either panel. Differences in neutralization sensitivity between HCVpps were independent of genetic distances between E1E2 clones.

CONCLUSIONS

Neutralizing breadth of HCV antibodies should be defined using viruses spanning multiple tiers of neutralization sensitivity rather than panels selected solely for genetic diversity. We propose that this multitier reference panel could be adopted as a standard for the measurement of neutralizing antibody potency and breadth, facilitating meaningful comparisons of neutralization results from vaccine studies in different laboratories.

"Thanks for hearing me out": Voices of social work students during COVID-19

As social work educators and students, the COVID-19 pandemic impacted our teaching and learning in challenging ways. We embarked on a qualitative research study to better understand the ways in which the pandemic was affecting the social work students in our program. Three faculty mentors worked collaboratively with five social work students across BSW, MSW, and PhD programs to interview 66 BSW and MSW students about their experiences, challenges, and hopes during the early months of the pandemic. BSW and MSW students led the analysis and early dissemination for the project. This essay describes the unique experiences of social work students by using a research poem to capture the emotional and experiential aspects of the students we interviewed.

A plasmid DNA-launched SARS-CoV-2 reverse genetics system and coronavirus toolkit for COVID-19 research

The recent emergence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the underlying cause of Coronavirus Disease 2019 (COVID-19), has led to a worldwide pandemic causing substantial morbidity, mortality, and economic devastation. In response, many laboratories have redirected attention to SARS-CoV-2, meaning there is an urgent need for tools that can be used in laboratories unaccustomed to working with coronaviruses. Here we report a range of tools for SARS-CoV-2 research. First, we describe a facile single plasmid SARS-CoV-2 reverse genetics system that is simple to genetically manipulate and can be used to rescue infectious virus through transient transfection (without in vitro transcription or additional expression plasmids). The rescue system is accompanied by our panel of SARS-CoV-2 antibodies (against nearly every viral protein), SARS-CoV-2 clinical isolates, and SARS-CoV-2 permissive cell lines, which are all openly available to the scientific community. Using these tools, we demonstrate here that the controversial ORF10 protein is expressed in infected cells. Furthermore, we show that the promising repurposed antiviral activity of apilimod is dependent on TMPRSS2 expression. Altogether, our SARS-CoV-2 toolkit, which can be directly accessed via our website at https://mrcppu-covid.bio/, constitutes a resource with considerable potential to advance COVID-19 vaccine design, drug testing, and discovery science.

Standardizing ordinal subadult age indicators: Testing for observer agreement and consistency across modalities

Skeletal and dental data for subadult analyses obtained from dry bones or various types of medical images, such as computed tomography (CT) scans or conventional radiographs/x-rays, should be consistent and repeatable to ensure method applicability across modalities and support combining study samples. The present study evaluates observer agreement of epiphyseal fusion and dental development stages obtained on CT scans of a U.S. sample and the consistency of epiphyseal fusion stages between CT scans and projected scan radiographs/scout images (U.S. CT sample), and between dry bones and conventional x-rays (Colombian osteological sample). Results show that both intra- and interobserver agreements of scores on CT scans were high (intra: mean Cohen's kappa=0.757-0.939, inter: mean Cohen's kappa=0.773-0.836). Agreements were lower for dental data (intra: mean Cohen's kappa=0.757, inter: mean Cohen's kappa=0.773-0.0.820) compared to epiphyseal fusion data (intra: mean Cohen's kappa=0.939, inter: mean Cohen's kappa=0.807-0.836). Consistency of epiphyseal fusion stages was higher between dry bones and conventional x-rays than between CT scans and scout images (mean Cohen's kappa=0.708-0.824 and 0.726-0.738, respectively). Differences rarely surpassed a one-stage value between observers or modalities. The complexity of some ossification patterns and superimposition had a greater negative impact on agreement and consistency rates than observer experience. Results suggest ordinal subadult skeletal data can be collected and combined across modalities.

Development of a structural epitope mimic: an idiotypic approach to HCV vaccine design

HCV vaccine development is stymied by the high genetic diversity of the virus and the variability of the envelope glycoproteins. One strategy to overcome this is to identify conserved, functionally important regions—such as the epitopes of broadly neutralizing antibodies (bNAbs)—and use these as a basis for structure-based vaccine design. Here, we report an anti-idiotype approach that has generated an antibody that mimics a highly conserved neutralizing epitope on HCV E2. Crucially, a mutagenesis screen was used to identify the antibody, designated B2.1 A, whose binding characteristics to the bNAb AP33 closely resemble those of the original antigen. Protein crystallography confirmed that B2.1 A is a structural mimic of the AP33 epitope. When used as an immunogen B2.1 A induced antibodies that recognized the same epitope and E2 residues as AP33 and most importantly protected against HCV challenge in a mouse model.

Prospective randomized comparison of two different sized percutaneous endoscopically placed gastrostomy tubes

We performed a prospective randomised study of two different sized percutaneous endoscopic gastrostomy (PEG) tubes to determine if tube size influenced the incidence of PEG-related complications. Patients were given prophylactic cefuroxime, if not already on antibiotics at the time of PEG insertion. Fifty-two PEGs were successfully placed, 26 in each group. Most patients who required a PEG had suffered a cerebrovascular event (82.7%). There were no procedure-related deaths. The mean ages (standard deviation) for the 12 and 20 French Gauge (FG) groups were 78.7 (8.9) and 73.9 (14.4) years, respectively, with no statistical difference. There were no significant differences in mortality (9 deaths in the 12 FG and 11 deaths in the 20 FG groups), number of peristomal infections (8 infections in the 12 FG and 12 infections in the 20 FG groups), episodes of leakage (12 leakages in the 12 FG and 17 leakages in the 20 FG groups) or tube blockage (2 blockage episodes in the 12 FG and 1 blockage episode in the 20 FG groups) between the two groups over a follow-up period of 190 days. The incidence of insertion- and feeding-related complications was thus not influenced by tube size. As the smaller PEG tubes were easier and less traumatic to insert we conclude that there are grounds for considering the more widespread use of the narrower diameter 12 FG PEG tubes.

Characterization of neogenin-expressing neural progenitor populations and migrating neuroblasts in the embryonic mouse forebrain

Many studies have demonstrated a role for netrin-1-deleted in colorectal cancer (DCC) interactions in both axon guidance and neuronal migration. Neogenin, a member of the DCC receptor family, has recently been shown to be a chemorepulsive axon guidance receptor for the repulsive guidance molecule (RGM) family of guidance cues [Rajagopalan S, Deitinghoff L, Davis D, Conrad S, Skutella T, Chedotal A, Mueller B, Strittmatter S (2004) Neogenin mediates the action of repulsive guidance molecule. Nat Cell Biol 6:755-762]. Here we show that neogenin is present on neural progenitors, including neurogenic radial glia, in the embryonic mouse forebrain suggesting that neogenin expression is a hallmark of neural progenitor populations. Neogenin-positive progenitors were isolated from embryonic day 14.5 forebrain using flow cytometry and cultured as neurospheres. Neogenin-positive progenitors gave rise to neurospheres displaying a high proliferative and neurogenic potential. In contrast, neogenin-negative forebrain cells did not produce long-term neurosphere cultures and did not possess a significant neurogenic potential. These observations argue strongly for a role for neogenin in neural progenitor biology. In addition, we also observed neogenin on parvalbumin- and calbindin-positive interneuron neuroblasts that were migrating through the medial and lateral ganglionic eminences, suggesting a role for neogenin in tangential migration. Therefore, neogenin may be a multi-functional receptor regulating both progenitor activity and neuroblast migration in the embryonic forebrain.

Preoperative esophageal manometry does not predict postoperative dysphagia following anti-reflux surgery

This prospective study was undertaken to determine the value of manometric studies in predicting postoperative dysphagia in patients undergoing laparoscopic Toupet fundoplication. Two hundred and twenty-nine out of 401 patients (57%) had preoperative dysphagia, and 26 patients had late postoperative dysphagia (6.5%). Eight patients who had no preoperative dysphagia developed dysphagia following surgery. There were no significant differences in esophageal motility for patients without postoperative dysphagia (n = 375) compared with those with postoperative dysphagia (n = 26). Among patients with postoperative dysphagia as a new symptom (n = 8), six had normal preoperative distal esophageal pressures, and none had esophageal hypomotility. In those with both pre- and postoperative dysphagia 15 of 18 had normal esophageal motility and hypomotility was only found in one. The positive predictive values of distal esophageal hypomotility and other measures for postoperative dysphagia are poor. In conclusion, preoperative manometry does not predict postoperative dysphagia following laparoscopic Toupet partial fundoplication.

Distal colonic motor activity in four subgroups of patients with irritable bowel syndrome

With the aim of improving end organ treatment, we describe a new system of classifying irritable bowel syndrome (IBS) according to clinical features into four groups, spastic colon syndrome (SCS), functional diarrhea (FD), diarrhea-predominant spastic colon syndrome (DPSCS), and midgut dysmotility (MGD). The aim of the study was to investigate fasting and postprandial distal colonic motility in the four groups of patients and to compare the results with normal controls. Distal colonic motility studies were performed in the unprepared colon. 2.5-hr recordings were made from four channels with a standard meal administered at 0.5 hr. The intubated colon was treated as a study segment and data analyzed for study segment activity index (SSAI) and number and mean amplitude of pressure peaks over 30-min epochs. Patients with SCS had significantly higher (P < 0.05) mean amplitude of pressure peaks (60 min, 120 min) and SSAI (120 min) than controls and patients with FD, DPSCS, and MGD. In contrast, patients with FD and DPSCS had significantly (P < 0.05) lower postprandial SSAI than controls and patients with SCS (60 min, 120 min). With the exception of raised postprandial mean amplitude of pressure peaks (120 min), MGD patients had normal distal colonic motility. Division of IBS patients into subgroups has highlighted significant differences in distal colonic motility that provide insights into etiopathogenesis and should assist targeting of current and newly developed therapies, particularly receptor active agents.

Intestinal motility

This review covers the recent advances that have been made in intestinal motility. Failure to stimulate the cephalic response when enteral tube feeding via the nasogastric route is important in contributing to enteral tube feeding related diarrhoea, which cannot be initially overcome by the use of fibre containing feeds. Dysfunction of the nervous system and visceral hypersensitivity appear to be important in contributing to the symptoms associated with irritable bowel syndrome.

Ventricular fibrillation following butane gas inhalation

We report a case of out of hospital defibrillation in a 15-year-old schoolgirl who developed ventricular fibrillation (VF) in association with butane gas inhalation. Although defibrillation performed by an attending paramedic was successful in restoring a cardiac output, her clinical course was complicated by severe neurological impairment. Reports of successful resuscitation following volatile substance abuse are rare and we believe this is the first documented evidence of VF associated with butane gas. This case illustrates the tragedy of such abuse in fit young people and we briefly review the literature.

Crystallization and preliminary X-ray diffraction studies on a recombinant isopenicillin N synthase from Cephalosporium acremonium

Recombinant isopenicillin N synthase from Cephalosporium acremonium was expressed in Escherichia coli and the protein was purified. After nearly 5000 crystallization trials, the apo enzyme was crystallized by the hanging drop vapour diffusion technique, using polyethylene glycol and lithium sulphate as precipitants. Two crystal forms have been obtained with either octahedral or elongated prismatic habits. The larger octahedral crystals (0.1 mm over-all dimensions) belong to space group I4 with unit cell dimensions of a = b = 124.7 A, c = 156.9 A, and diffract X-rays to about 3.5 A resolution at synchrotrons. The crystallographic asymmetric unit contains a dimer.

Rapid resolution following chemotherapy of Broca's dysphasia due to recurrent anaplastic astrocytoma

A middle-aged man re-presented with a Broca's aphasia due to a recurrent fronto-cingulate anaplastic astrocytoma. Although the language disturbance did not improve with dexamethasone therapy, within 4 weeks of treatment with procarbazine, CCNU and vincristine, the dysphasia had almost completely resolved. The anatomico-functional aspects and possible mechanisms of production and resolution of the aphasia are discussed. Assessment of dysphasias in patients undergoing intensive therapy for brain neoplasms is often neglected, but it can provide good objective information about the efficacy of therapy.

The influence of the brain hormone on retention of blood in the mid-gut of the mosquito Aedes aegypti (L.). III. The involvement of the ovaries and ecdysone

Most female mosquitoes require a blood-meal in order to produce mature oöcytes. An egg development neurosecretory hormone (EDNH), which is produced in the medial neurosecretory cells (m.n.c.) of the brain and stored in the corpus cardiacum, is released into the haemolymph following the ingestion of blood and is essential for the promotion of ovarian development to maturity. It has been shown that a factor from the m.n.c., presumably EDNH, is necessary if the blood-meal is to be retained in the mid-gut until the oöcytes approach maturity. The present paper shows that retention is not a direct result of the action of EDNH, but is dependent on the ovaries and may well involve ecdysone. Removal of the ovaries before a blood-meal leads to early haem-defaecation, but delay can be restored by injection of ecdysterone. Sub-threshold feeders and mosquitoes decapitated immediately after the intake of blood, each of which would be expected to eliminate the blood-meal early, also show a delay in the onset of haem-defaecation when injected with ecdysterone. Further, both in ovariectomized insects and sub-threshold feeders the time of onset of haem-defaecation is associated with the dose of ecdysterone given.

The influence of the brain hormone on retention of blood in the mid-gut of the mosquito Aedes aegypti (L). II. Early elimination following removal of the medial neurosecretory cells of the brain

Development of the oöcytes beyond the resting stage to maturity in mosquitoes is triggered by an egg development neurosecretory hormone from the brain. This hormone is produced by the medial neurosecretory cells of the pars intercerebralis, and in anautogenous species is stored in the corpus cardiacum until a blood-meal is taken. Removal of the head of the mosquito Aedes aegypti (L.), shortly after completion of a blood-meal, has previously been shown not only to prevent oöcyte maturation, but also to result in early elimination of the blood-meal. The work described in this paper shows that it is a factor originating in the medial neuro­-secretory cells, presumably egg development neurosecretory hormone, which is essential if the blood-meal is to be retained in the mid-gut until the oöcytes are nearing maturity.

The influence of the brain hormone on retention of blood in the mid-gut of the mosquito Aedes aegypti (L.)

Development of the oöcytes after a blood-meal in the mosquito Aedes aegypti occurs in two phases: initiation , which is independent of hormonal action, and promotion to maturity, which is dependent on a neurosecretory hormone from the brain (acting through the endocrine system of the thorax). During the promotion-phase, material for the growth of the oöcytes is mobilized from the blood in the mid-gut. The work described here explores the possibility and confirms that one of the functions of the brain hormone is to retain the blood in the mid-gut until development of the oöcytes is complete.

On Some Morphological Aspects of Microcephalic Idiocy

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