The European Society for Veterinary Virology: review and prospects

Jestin André. La Société européenne de virologie vétérinaire : bilan et perspectives. In: Bulletin de l'Académie Vétérinaire de France tome 157 n°3, 2004. pp. 75-77

Replication of porcine circoviruses

Porcine circoviruses are circular single-stranded DNA viruses that infect swine and wild boars. Two species of porcine circoviruses exist. Porcine circovirus type 1 is non pathogenic contrary to porcine circovirus type 2 which is associated with the disease known as Post-weaning Multisystemic Wasting Syndrome. Porcine circovirus DNA has been shown to replicate by a rolling circle mechanism. Other studies have revealed similar mechanisms of rolling-circle replication in plasmids and single-stranded viruses such as Geminivirus. Three elements are important in rolling-circle replication: i) a gene encoding initiator protein, ii) a double strand origin, and iii) a single strand origin. However, differences exist between viruses and plasmids and between viruses. Porcine circovirus replication probably involves a "melting pot" rather than "cruciform" rolling-circle mechanism

One Health EJP, european joint programming and funding of research on foodborne zoonoses

L’EJP One health est un projet européen de recherche destiné à éclairer la décision publique dans le domaine de la sécurité sanitaire des aliments (One Health EJP). Il a pour objectif de contribuer à renforcer les liens existants entre santé animale, santé humaine et l’environnement selon la démarche “Une seule santé” (Jestin & Davoust, 2015; Parodi, 2018). Co-financé par la Commission Européenne et les états membres de l’Union Européenne, ce projet regroupe 39 partenaires de 19 états membres. Ces centres publics de recherche, soit en santé publique soit en santé animale, mènent des travaux de recherche sur les zoonoses alimentaires, l’antibiorésistance et les maladies émergentes alimentaires tout en assurant les mandats de référence correspondants. La mise en œuvre de la démarche “Une seule santé” se fait par la mobilisation des deux communautés “Med” et “Vet”, dans une approche multidisciplinaire. Les priorités thématiques de recherche sont définies par les instituts de recherche après consultation des agences nationales et européennes d’évaluation des risques. Par cette approche l’EJP One Health est un projet de recherche destinée à générer des informations scientifiques essentielles à l’analyse et à l’évaluation des risques sanitaires, et à ce titre est en appui à la décision publique.The One Health concept recognizes that the human health is tightly connected to the health of animals and to the environment, i.e. that animal feed, human food, animal and human health, and environmental contamination are closely linked. These are the main focus of our European joint programme (EJP). One reference laboratory from the public health / medicine domain and one reference laboratory from the food / veterinary domain are associated within a network of 39 European laboratories and research centers, distributed in 19 participating member states, with the aim to reach significant advances in the fields of foodborne zoonoses, antimicrobial resistance and emerging threats within a global One Health approach. Most of these laboratories have reference responsibilities, representing a sustainable framework for an integrated research community. The One Health EJP aims at reinforcing collaboration between institutes by enhancing transdisciplinary cooperation and integration of activities. The One health EJP is a policy driven project, contributing to strengthen the decision of the policy makers

Modification of PCV-2 virulence by substitution of the genogroup motif of the capsid protein

Porcine circovirus type 2 (PCV-2) is the causal agent of the post-weaning multisystemic wasting syndrome (PMWS). PCV-2 are small single-stranded circular DNA viruses clustered into two main genogroups: PCV-2a and PCV-2b. Each genogroup present a specific highly-conserved motif of six amino acids (between amino acids 86 and 91) in the PCV-2 capsid protein. The aim of this study was to verify whether the motif located in the capsid protein and specific to each PCV-2 genogroup contributes to virulence. Two parental DNA clones, PCV-2a and PCV-2b, were constructed as well as two mutants DNA clones, PCV-2a/motif 2b and PCV-2b/motif 2a by exchanging the capsid motif of each genogroup. The four DNA clones were characterized in vitro as well as in vivo. Cells transfected by the four DNA clones produced infectious viruses. In specific-pathogen-free piglets transfected by the four infectious DNA clones, PCV-2b/motif 2a virulence was not attenuated while the PCV-2a/motif 2b virulence was drastically reduced compared to their parent virulence. These results suggest that the amino acids between positions 86 and 91 of the capsid protein are determinant for the virulence of isolates. However, the environment of this motif seems also involved

One health concept, definition, human-animal-environment interactions in parasitology and emerging viruses

Jestin André, Dupouy-Camet Jean. Le concept « une seule santé », définition, relations homme-animal-environnement en parasitologie et en émergences virales. In: Bulletin de l'Académie Vétérinaire de France tome 172 n°1, 2019. pp. 110-111

Protéines à motif tripartite (TRIM) chez le porc (Sus scrofa) et réplication du rétrovirus endogène porcin

Les études des interactions entre cellules hôtes et rétrovirus ont conduit à définir le concept de restriction virale dont les facteurs constituent une part de l'immunité innée des cellules hôtes. Ces facteurs contribuent au contrôle des rétrovirus endogènes (ERV) dont l'émergence peut être associée à certaines pathologies telles que des leucémies ou des immunodéficiences. Chez le porc, certains ERV (PERV) sont réplicatifs, pourtant aucune pathologie ne leur a, à ce jour, été associée. Les mécanismes de restriction virale impliqués dans ce phénomène ont fait l'objet de nombreuses études. Elles n'ont cependant concerné que certains facteurs. Les protéines porcines à motif tripartite (poTRIM) n'ont ainsi fait l'objet que de peu d'études. Pourtant, de nombreux membres de cette famille participent à la restriction virale chez d'autres organismes que le porc. La présente étude s'intéresse par conséquent aux orthologues porcins de ces protéines et à leur relation avec les PERV. L'élaboration d'une stratégie d'expression de ces protéines dans un modèle humain, sensible à l'infection par le PERV nous a permis d'évaluer et de caractériser les effets des TRIM sur le cycle infectieux du PERV. Cette stratégie a mis en évidence une activité de restriction par TRIM8 tandis que TRIM44 semble au contraire agir en faveur de la réplication virale. En ce qui concerne poTRIM11, elle favorise l'entrée du PERV tout en inhibant son expression. L'étude a également confirmé l'insensibilité du PERV vis-à-vis de poTRIM5a. L'ensemble de ces résultats contribuent à la compréhension de la relation entre la réplication des PERV et le contrôle mené par son hôte.From studies of pathogens and their host interaction has emerged the concept of viral restriction considered to be part of an innate immune system. These factors contribute to the control of endogenous retroviruses (ERV) whose emergence may be associated with several diseases such as leukemia or immunodeficiency. Three subgroups of the porcine ERV-g-1 group (PERV) are replicative. Nevertheless, these PERVs are not associated with any pathology in the pig. Several studies have been performed on viral restriction mechanism capabilities of the pig but these covered a very limited number of restriction factors. Regarding the porcine tripartite motif-containing (poTRIM) proteins, knowledge is weak although several members of this family have proved to be implicated in the viral restriction of other species. The purpose of this study is to investigate the relationship between these orthologous poTRIMs proteins and replicating PERVs. In order to explore this potential interaction, a TRIM protein expressing model in human cells, known to be sensitive to the PERV infection, has been developed. It has enabled us to assess and characterize potential TRIMs effects on the PERV infection cycle. We equally identified poTRIM8 as a restriction factor. Conversely, poTRIM44 seems to act as an enhancer of the PERV infection, while, TRIM11 displayed ambiguous effects including an enhancer effect of the early infectious stages and an inhibitor activity of the late infectious stages. In this study, we also confirmed the PERV insensitivity to the porcine TRIM5a protein. Finally, this work aims at contributing to the understanding of the relationship between PERV replication and their control leading by the host cells.RENNES1-Bibl. électronique (352382106) / SudocSudocFranceF

Acute induction of cell death-related IFN stimulated genes (ISG) differentiates highly from moderately virulent CSFV strains

Classical swine fever (CSF) severity is dependent on the virulence of the CSF virus (CSFV) strain. The earliest event detected following CSFV infection is a decrease in lymphocytes number. With some CSFV strains this leads to lymphopenia, the severity varying according to strain virulence. This lymphocyte depletion is attributed to an induction of apoptosis in non-infected bystander cells. We collected peripheral blood mononuclear cells (PBMC) before and during 3 days post-infection with either a highly or moderately virulent CSFV strain and subjected them to comparative microarray analysis to decipher the transcriptomic modulations induced in these cells in relation to strain virulence. The results revealed that the main difference between strains resided in the kinetics of host response to the infection: strong and immediate with the highly virulent strain, progressive and delayed with the moderately virulent one. Also although cell death/apoptosis-related IFN stimulated genes (ISG) were strongly up-regulated by both strains, significant differences in their regulation were apparent from the observed differences in onset and extent of lymphopenia induced by the two strains. Furthermore, the death receptors apoptotic pathways (TRAIL-DR4, FASL-FAS and TNFa-TNFR1) were also differently regulated. Our results suggest that CSFV strains might exacerbate the interferon alpha response, leading to bystander killing of lymphocytes and lymphopenia, the severity of which might be due to the host’s loss of control of IFN production and downstream effectors regulation