Probes for INS

Effective therapeutics have been developed against acute Ebola virus disease (EVD) in both humans and experimentally infected nonhuman primates. However, the risk of viral persistence and associated disease recrudescence in survivors receiving these therapeutics remains unclear. In contrast to rhesus macaques that survived Ebola virus (EBOV) exposure in the absence of treatment, we discovered that EBOV, despite being cleared from all other organs, persisted in the brain ventricular system of rhesus macaque survivors that had received monoclonal antibody (mAb) treatment. In mAb-treated macaque survivors, EBOV persisted in macrophages infiltrating the brain ventricular system, including the choroid plexuses. This macrophage infiltration was accompanied by severe tissue damage, including ventriculitis, choroid plexitis, and meningoencephalitis. Specifically, choroid plexus endothelium-derived EBOV infection led to viral persistence in the macaque brain ventricular system. This resulted in apoptosis of ependymal cells, which constitute the blood-cerebrospinal fluid barrier of the choroid plexuses. Fatal brain-confined recrudescence of EBOV infection manifested as severe inflammation, local pathology, and widespread infection of the ventricular system and adjacent neuropil in some of the mAb-treated macaque survivors. This study highlights organ-specific EBOV persistence and fatal recrudescent disease in rhesus macaque survivors after therapeutic treatment and has implications for the long-term follow-up of human survivors of EVD.

Low-grade inflammation is the hallmark of non-alcoholic fatty liver diseases (NAFLD) and non-alcoholic steatohepatitis (NASH). The leakage of microbiota-derived products can contribute to liver inflammation during NAFLD/NASH development. Here, we assessed the roles of gut microbial DNA-containing extracellular vesicles (mEVs) in regulating liver cellular abnormalities in the course of NAFLD/NASH.We performed studies with Vsig4-/- , C3-/- , cGAS-/- , and their wild-type littermate mice. Vsig4+ macrophage population and bacterial DNA abundance were examined in both mouse and human liver by either flow cytometric or immunohistochemistry analysis. Gut mEVs were adoptively transferred into Vsig4-/- , C3-/- , cGAS-/- , or littermate WT mice, and hepatocyte inflammation and HSC fibrogenic activation were measured in these mice.Non-alcoholic fatty liver diseases and non-alcoholic steatohepatitis development was concomitant with a diminished liver Vsig4+ macrophage population and a marked bacterial DNA enrichment in both hepatocytes and HSCs. In the absence of Vsig4+ macrophages, gut mEVs translocation led to microbial DNA accumulation in hepatocytes and HSCs, resulting elevated hepatocyte inflammation and HSC fibrogenic activation. In contrast, in lean WT mice, Vsig4+ macrophages remove gut mEVs from bloodstream through a C3-dependent opsonization mechanism and prevent the infiltration of gut mEVs into hepatic cells. Additionally, Vsig4-/- mice more quickly developed significant liver steatosis and fibrosis than WT mice after Western diet feeding. In vitro treatment with NASH mEVs triggered hepatocyte inflammation and HSC fibrogenic activation. Microbial DNAs are key cargo for the effects of gut mEVs by activating cGAS/STING.Accumulation of microbial DNAs fuels the development of NAFLD/NASH-associated liver abnormalities.

Epstein-Barr virus (EBV), defined as a group I carcinogen by the World Health Organization (WHO), is present in the tumour cells of patients with different forms of B-cell lymphoma, including Burkitt lymphoma, Hodgkin lymphoma, post-transplant lymphoproliferative disorders, and, most recently, diffuse large B-cell lymphoma (DLBCL). Understanding how EBV contributes to the development of these different types of B-cell lymphoma has not only provided fundamental insights into the underlying mechanisms of viral oncogenesis, but has also highlighted potential new therapeutic opportunities. In this review, we describe the effects of EBV infection in normal B-cells and we address the germinal centre model of infection and how this can lead to lymphoma in some instances. We then explore the recent reclassification of EBV+ DLBCL as an established entity in the WHO fifth edition and ICC 2022 classifications, emphasising the unique nature of this entity. To that end, we also explore the unique genetic background of this entity and briefly discuss the potential role of the tumour microenvironment in lymphomagenesis and disease progression. Despite the recent progress in elucidating the mechanisms of this malignancy, much work remains to be done to improve patient stratification, treatment strategies, and outcomes.

Senecavirus A (SVA) has been demonstrated to be a causative agent for vesicular disease in swine. It is clinically indistinguishable from other agents that cause vesicular disease such as foot-and-mouth disease virus (FMDV), which is a reportable foreign animal disease (FAD). Thus, an investigation is initiated to rule out FMDV every time a vesicle is observed. Senecavirus A has now been reported across the Americas and Asia, and it appears the ecology of this virus has changed from sporadic infections to an endemic disease in some areas. In addition to vesicular disease, there have also been reports of increased neonatal mortality on affected sow farms. Knowledge about the pathogenesis of SVA in swine can provide many benefits to the swine industry. Understanding how long the virus can be detected in various sample types after infection can aide in choosing the correct samples to collect for diagnosis. In addition, the duration of virus shedding can help determine measures to control virus spread between animals. Prevention of SVA infection and disease with an efficacious vaccine could improve swine welfare, minimize SVA transmission, and reduce the burden of FAD investigations.

Introduction: Avian influenza (AI) is a highly contagious disease that, during the last few years, has been occurring with increased frequency in Europe. Immunohistochemistry (IHC) is commonly used to demonstrate AI virus (AIV) antigens in affected tissues. Recent studies suggest that RNAscope in-situ hybridization outperforms IHC for viral detection in human tissues. This study aims to validate and compare RNAscope with IHC routinely used for the detection of AIV. Materials and Methods: RNAscope targeting the Influenza M gene and anti-influenza A virus nucleoprotein IHC were first performed on AIV positive (n=7) and negative tissues (n=6) collected between 2009 and 2021, including seven avian species (chicken, duck, guinea fowl, quail, turkey, goose and houbara bustard) and three different AIVs (H5N8, H5N9, H6N1). A Tissue Micro-Array (TMA) with 132 cores, including 44 triplicated organs (brain, lung, heart, spleen, pancreas) originating from nine mule ducks naturally infected with H5N8 (2020) was then used to compare techniques through computer-assisted quantitative analysis. Results: AIV nucleoprotein and M gene were detected in all positive tissues of all species and for all AIVs. All uninfected birds were negative. While IHC appeared affected by autolysis, the quality of the RNAscope signal remained unchanged. On the TMA, viral detection efficacy measurements revealed higher sensitivity with RNAscope compared with IHC, in particular for brain and heart tissues. Conclusions: These preliminary results indicate that RNAscope is a suitable and sensitive tool for the detection of AIV and encourage the development of additional probes for the detection of AIV subtypes.

Dynamic interactions between host, pathogen and host-associated microbiome dictate infection outcomes. Pathogens including Batrachochytrium dendrobatidis (Bd) threaten global biodiversity, but conservation efforts are hindered by limited understanding of amphibian host, Bd and microbiome interactions. We conducted a vaccination and infection experiment using Eastern hellbender salamanders (Cryptobranchus alleganiensis alleganiensis) challenged with Bd to observe infection, skin microbial communities and gene expression of host skin, pathogen and microbiome throughout the experiment. Most animals survived high Bd loads regardless of their vaccination status and vaccination did not affect pathogen load, but host gene expression differed based on vaccination. Oral vaccination (exposure to killed Bd) stimulated immune gene upregulation while topically and sham-vaccinated animals did not significantly upregulate immune genes. In early infection, topically vaccinated animals upregulated immune genes but orally and sham-vaccinated animals downregulated immune genes. Bd increased pathogenicity-associated gene expression in late infection when Bd loads were highest. The microbiome was altered by Bd, but there was no correlation between anti-Bd microbe abundance or richness and pathogen burden. Our observations suggest that hellbenders initially generate a vigorous immune response to Bd, which is ineffective at controlling disease and is subsequently modulated. Interactions with antifungal skin microbiota did not influence disease progression.

Introduction Le virus ZIKA (ZIKV) est un virus transmis par les moustiques et par le sperme, avec un fort potentiel d’émergence. Lors d’une infection pendant la grossesse, ce virus peut entraîner des anomalies fœtales cérébrales mais aussi uro-génitales, comme révélé lors de l’épidémie de 2015-2016 dans les Amériques. Description L’objectif de notre étude est de déterminer la permissivité du rein fœtal au ZIKV et les conséquences de cette infection. Méthodes Pour cela nous avons infecté ex vivo avec ZIKV des cultures organotypiques de reins fœtaux disséqués à partir de produits d’IVG obtenus entre 11 et 14 semaines d’aménorrhée. Résultats Nos résultats montrent que le ZIKV se réplique efficacement dans le rein fœtal, comme attesté par l’augmentation de l’ARN viral dans les cultures au cours du temps et par la détection in situ en RNAscope de l’ARN brin négatif produit lors de la réplication du virus. L’ARN réplicatif du ZIKV a été retrouvé dans le tissu interstitiel ainsi que dans des tubules et des glomérules en formation. Les cellules cibles du virus ont été identifiées par immunohistochimie à l’aide d’anticorps contre la protéine virale non structurale NS2b et contre des marqueurs cellulaires. Le virus est retrouvé au niveau du compartiment interstitiel dans des macrophages CD68+ et des fibroblastes SMA+ et au niveau des cellules épithéliales tubulaires CK18+. La localisation dans des cellules glomérulaires WT1+ reste à déterminer. L’infection virale n’a pas d’effet délétère majeur sur la morphologie, la viabilité et la prolifération cellulaire du rein à 6 jours post-infection. Conclusion En conclusion, ces résultats révèlent pour la première fois que le rein fœtal est permissif au virus Zika. Il serait nécessaire d’évaluer l’effet à plus long terme de l’infection sur le rein en développement. Notre modèle ex vivo pourrait permettre de tester l’efficacité d’antiviraux visant à empêcher la réplication du ZIKV dans le rein foetal.