Picornaviruses replicate their genomes in association with cellular membranes. While enteroviruses are believed to utilize membranes of the early secretory pathway, the origin of the membranes used by foot-and-mouth disease virus (FMDV) for replication are unknown. Secretory-vesicle traffic through the early secretory pathway is mediated by the sequential acquisition of two distinct membrane coat complexes, COPII and COPI, and requires the coordinated actions of Sar1, Arf1 and Rab proteins. Sar1 is essential for generating COPII vesicles at endoplasmic reticulum (ER) exit sites (ERESs), while Arf1 and Rab1 are required for subsequent vesicle transport by COPI vesicles. In the present study, we have provided evidence that FMDV requires pre-Golgi membranes of the early secretory pathway for infection. Small interfering RNA depletion of Sar1 or expression of a dominant-negative (DN) mutant of Sar1a inhibited FMDV infection. In contrast, a dominant-active mutant of Sar1a, which allowed COPII vesicle formation but inhibited the secretory pathway by stabilizing COPII coats, caused major disruption to the ER–Golgi intermediate compartment (ERGIC) but did not inhibit infection. Treatment of cells with brefeldin A, or expression of DN mutants of Arf1 and Rab1a, disrupted the Golgi and enhanced FMDV infection. These results show that reagents that block the early secretory pathway at ERESs have an inhibitory effect on FMDV infection, while reagents that block the early secretory pathway immediately after ER exit but before the ERGIC and Golgi make infection more favourable. Together, these observations argue for a role for Sar1 in FMDV infection and that initial virus replication takes place on membranes that are formed at ERESs.
BackgroundInfluenza and its associated diseases are a major cause of morbidity and mortality. The United States Advisory Committee on Immunization Practices recommends influenza vaccination for everyone over 6 months of age. The failure of the flu vaccine in 2014–2015 demonstrates the need for a model that allows the rapid development of novel antivirals, universal/intra-seasonal vaccines, immunomodulators, monoclonal antibodies and other novel treatments. To this end we manufactured a new H3N2 influenza virus in compliance with Good Manufacturing Practice for use in the Human Viral Challenge Model.Methods and Strain SelectionWe chose an H3N2 influenza subtype, rather than H1N1, given that this strain has the most substantial impact in terms of morbidity or mortality annually as described by the Centre for Disease Control. We first subjected the virus batch to rigorous adventitious agent testing, confirmed the virus to be wild-type by Sanger sequencing and determined the virus titres appropriate for human use via the established ferret model. We built on our previous experience with other H3N2 and H1N1 viruses to develop this unique model.Human Challenge and ConclusionsWe conducted an initial safety and characterisation study in healthy adult volunteers, utilising our unique clinical quarantine facility in London, UK. In this study we demonstrated this new influenza (H3N2) challenge virus to be both safe and pathogenic with an appropriate level of disease in volunteers. Furthermore, by inoculating volunteers with a range of different inoculum titres, we established the minimum infectious titre required to achieve reproducible disease whilst ensuring a sensitive model that can be translated to design of subsequent field based studies.Trial RegistrationClinicalTrials.gov NCT02525055
BackgroundHuman Rhinovirus infection is an important precursor to asthma and chronic obstructive pulmonary disease exacerbations and the Human Viral Challenge model may provide a powerful tool in studying these and other chronic respiratory diseases. In this study we have reported the production and human characterisation of a new Wild-Type HRV-16 challenge virus produced specifically for this purpose.Methods and Stock DevelopmentA HRV-16 isolate from an 18 year old experimentally infected healthy female volunteer (University of Virginia Children’s Hospital, USA) was obtained with appropriate medical history and consent. We manufactured a new HRV-16 stock by minimal passage in a WI-38 cell line under Good Manufacturing Practice conditions. Having first subjected the stock to rigorous adventitious agent testing and determining the virus suitability for human use, we conducted an initial safety and pathogenicity clinical study in adult volunteers in our dedicated clinical quarantine facility in London.Human Challenge and ConclusionsIn this study we have demonstrated the new Wild-Type HRV-16 Challenge Virus to be both safe and pathogenic, causing an appropriate level of disease in experimentally inoculated healthy adult volunteers. Furthermore, by inoculating volunteers with a range of different inoculum titres, we have established the minimum inoculum titre required to achieve reproducible disease. We have demonstrated that although inoculation titres as low as 1 TCID50 can produce relatively high infection rates, the optimal titre for progression with future HRV challenge model development with this virus stock was 10 TCID50. Studies currently underway are evaluating the use of this virus as a challenge agent in asthmatics.Trial RegistrationClinicalTrials.gov NCT02522832
ObjectiveThis manuscript aims to provide an overview of the unique considerations and best practice principles associated with the manufacture of human viral challenge agents.ResultsConsiderations are discussed on the entire process from strain and viral source selection through manufacturing, safety and efficacy testing. The human viral challenge (HVC) model is an important tool to help accelerate the drug development process but producing viruses suitable for use in the model presents a unique set of challenges. There are many case by case decisions and risk assessments to consider and no clear international standard to produce viruses for this purpose. The authors present challenge virus manufacturing considerations from the current literature, regulatory guidance and their own direct experience in producing challenge viruses. The use of these viral stocks in clinical studies, as published in peer-reviewed journals, is also briefly described.Electronic supplementary materialThe online version of this article (10.1186/s13104-018-3636-7) contains supplementary material, which is available to authorized users.
TPS9116 Background: Mesenchymal stromal cells (MSCs) migrate to and incorporate into tumour stroma allowing them to act as vehicles for delivering anti-cancer therapies. TNF-related apoptosis inducing ligand (TRAIL) selectively induces apoptosis in malignant cells however short biological half-life has its limited therapeutic efficacy. We have transduced umbilical cord MSCs with a lentiviral vector to express TRAIL (MSCTRAIL). These cells trigger apoptosis selectively in cancer cells with evidence of synergistic activity with other systemic anti-cancer therapies. Given their immune-privileged nature we are delivering ex vivo pooled MSCTRAIL from third party donors without tissue matching or immunosuppression. Efficacy has been demonstrated using in vitro co-culture assays and in vivo in orthotopic lung metastasis murine model, showing regression of metastases following treatment with intravenous MSCTRAIL [1]. Methods: TACTICAL is a phase I/II trial assessing safety and efficacy of MSCTRAIL in combination with first line standard of care (SOC); pemetrexed (500mg/m2) and cisplatin (75mg/m2) and/or pembrolizumab (200mg), in treatment naïve patients with stage IIIB/IV metastatic lung adenocarcinoma. Patients have no actionable driver mutations and ECOG performance status 0-1. Phase I is a dose de-escalation study, patients receive SOC on day 1 and 4x108 MSCTRAIL cells on day 2 of a 21 day cycle for 3 cycles. A Bayesian adaptive design will recommend dose reductions if excessive toxicities occur. Primary outcomes are to determine recommended phase II dose along with safety and tolerability of MSCTRAIL. 46 patients will then be randomised into a multi-centre phase II double blind, placebo-controlled trial to receive SOC and either MSCTRAIL or placebo (1:1). Primary outcome is tumour response rate by RECIST (v 1.1) criteria at 12 weeks. Secondary outcomes include, best overall response, duration of response, progression free survival and overall survival. TACTICAL is the first clinical trial of this novel cell and gene therapy and if successful will pave the way for future allogeneic MSC therapy in cancer. 1. Loebinger, M.R., et al., Mesenchymal stem cell delivery of TRAIL can eliminate metastatic cancer. Cancer Res, 2009. 69(10): p. 4134-42. Clinical trial information: NCT03298763.
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