Innovative vaccine approach based on the use of novirhabdovirus-derived platform

Les Novirhabdovirus, tels que le Virus de la Septicémie Hémorragique Virale (vSHV) ou le virus de la Nécrose Hématopoiétique Infectieuse (vNHI) sont des rhabdovirus infectant les poissons à basse température. L’utilisation de systèmes de génétique inverse développés dans notre laboratoire ont permis, en manipulant le génome viral, de produire des virus recombinés exprimant à leur surface différents antigènes d’intérêt pour la vaccination contre des virus affectant les mammifères, dont l’homme. Dans cette communication, nous présentons le développement de vaccins contre le virus du Nil Occidental, un Flavivirus et contre un virus grippal. Dans ce dernier exemple, nous avons produit des Novirhabdovirus exprimant l’hémagglutinine HA, très immunogène, d’un virus grippal H1N1. Ces virus recombinés injectés chez la souris induisent une protection totale de ces souris immunisées face à une épreuve létale avec le virus grippal. Cette plateforme vaccinale présente de nombreux avantages : i) les virus recombinés sont faciles et rapides à produire en masse, ii) ils peuvent incor - porer n’importe quel antigène d’intérêt à leur surface, iii) ils ne nécessitent pas d’adjuvant lors des immunisations, iv) ils sont naturellement inactivés au-delà de 20°C, rendant ainsi inutile le processus d’inactivation.Novirhabdoviruses such as the Viral Hemorrhagic Septicemia Virus (VHSV) or the Infectious Hematopoietic Necrosis Virus (IHNV) are rhabdoviruses infecting fish at low temperature. The use of reverse genetics system developed in our laboratory allowed, by manipulating the viral genome, the recovery of recombinant virus expressing at the viral envelope various antigens of interest against animal or human viruses to vaccinate mammalian. In the current article, we present the generation of a new vaccine against the West Nile Virus, a Flavivirus and against influenza virus. In the latter example, we have produced recombinant Novirhabdoviruses expressing the hemagglutinin HA from H1N1 influenza virus. These recombinant viruses, when injected in mice, induce a complete protection of the immunized mice against a lethal challenge with influenza virus. That new vaccine platform offers several advantages i)The recombinant viruses are easy and fast to be mass produced ii) They can incorporate any antigen of interest at the viral envelope iii) Immunizations do not need adjuvant addition iv) They are naturally inactivated at temperature higher than 20°C, thus do not require any inactivation process

Les vecteurs viraux : outils modernes de vaccination

Les vaccins destinés aux animaux appartiennent à deux grandes catégories : les vaccins à agents vivants, et ceux à agents inertes. Depuis quelques années, dans chacune de ces catégories, les innovations technologiques ont considérablement amélioré et diversifié les stratégies vaccinales disponibles en fonction des contraintes liées à des préoccupations tant d’innocuité, que d’efficacité ou encore de nature économique. C’est dans ce cadre que l’INRA a depuis de nombreuses années orienté les efforts de recherche vers l’élaboration de nouveaux vaccins s’appuyant sur la mise au point de vecteurs viraux adaptés à diverses espèces animales et susceptibles de répondre aux exigences des filières animales. Dans cette revue, nous décrivons ainsi les principes d’obtention et le développement de vecteurs vaccinaux fondés sur l’emploi de poxvirus animaux à spectre d’hôte étroit (virus myxomateux), d’adenovirus humains ou animaux défectifs (c'est-à-dire ayant perdu toute capacité à se multiplier chez l’hôte) ainsi que de rhabdovirus de poissons modifiés par génétique inverse. Des exemples d’application de vaccination non seulement contre des maladies animales d’intérêt économique, mais aussi dans le cadre de modèles de pathologie comparée permettent d’illustrer le potentiel indiscutable de ces vecteurs viraux et d’envisager leur emploi pour le contrôle de maladies animales émergentes ou réémergentes en Europe

Whole-Body Analysis of a Viral Infection: Vascular Endothelium is a Primary Target of Infectious Hematopoietic Necrosis Virus in Zebrafish Larvae

The progression of viral infections is notoriously difficult to follow in whole organisms. The small, transparent zebrafish larva constitutes a valuable system to study how pathogens spread. We describe here the course of infection of zebrafish early larvae with a heat-adapted variant of the Infectious Hematopoietic Necrosis Virus (IHNV), a rhabdovirus that represents an important threat to the salmonid culture industry. When incubated at 24°C, a permissive temperature for virus replication, larvae infected by intravenous injection died within three to four days. Macroscopic signs of infection followed a highly predictable course, with a slowdown then arrest of blood flow despite continuing heartbeat, followed by a loss of reactivity to touch and ultimately by death. Using whole-mount in situ hybridization, patterns of infection were imaged in whole larvae. The first infected cells were detectable as early as 6 hours post infection, and a steady increase in infected cell number and staining intensity occurred with time. Venous endothelium appeared as a primary target of infection, as could be confirmed in fli1:GFP transgenic larvae by live imaging and immunohistochemistry. Disruption of the first vessels took place before arrest of blood circulation, and hemorrhages could be observed in various places. Our data suggest that infection spread from the damaged vessels to underlying tissue. By shifting infected fish to a temperature of 28°C that is non-permissive for viral propagation, it was possible to establish when virus-generated damage became irreversible. This stage was reached many hours before any detectable induction of the host response. Zebrafish larvae infected with IHNV constitute a vertebrate model of an hemorrhagic viral disease. This tractable system will allow the in vivo dissection of host-virus interactions at the whole organism scale, a feature unrivalled by other vertebrate models

Synthesis of 2-Amido-2,3-dihydro-1H-phenalene Derivatives as New Conformationally Restricted Ligands for Melatonin Receptors

Tetrahydroanthracene, tetrahydrophenanthrene, and tetrahydrophenalene moieties were used to design novel constrained melatoninergic agents. Compounds 1 and 2 were synthesized from the cyclization of the aryl succinic acids 6a,b followed by catalytic reduction, Curtius degradation to the amino derivatives, and acetylation. The phenalene derivatives 3 were prepared by cyclization of the aza lactones of the corresponding R-N-acetyl amino acids. The ketone derivatives were reduced directly by catalytic hydrogenation to produce the compounds 3. The different compounds were evaluated in vitro in binding assays using 2-[ 125 I]iodomelatonin and chicken brain membranes. Melatonin and 2-acetamido-8-methoxytetralin were used as the reference compounds. The results showed the superiority of the dihydrophenalene framework 3 over those of tetrahydroanthracene and tetrahydrophenanthrene. 3a had relatively good affinity for melatonin receptors (K i ) 28.7 n

Veterinary Research reviewer acknowledgement 2013

International audienceContributing reviewersThe Veterinary Research editorial team would sincerely like to thank all of our reviewers who contributed to peer review for the journal in 2013

Heterologous Exchanges of the Glycoprotein and the Matrix Protein in a Novirhabdovirus

Infectious hematopoietic necrosis virus (IHNV) and viral hemorrhagic septicemia virus (VHSV) are two salmonid rhabdoviruses replicating at low temperatures (14 to 20°C). Both viruses belong to the Novirhabdovirus genus, but they are only distantly related and do not cross antigenically. By using a recently developed reverse-genetic system based on IHNV (S. Biacchesi et al., J. Virol. 74:11247-11253, 2000), we investigated the ability to exchange IHNV glycoprotein G with that of VHSV. Thus, the IHNV genome was modified so that the VHSV G gene replaced the complete IHNV G gene. A recombinant virus expressing VHSV G instead of IHNV G, rIHNV-Gvhsv, was generated and was shown to replicate as well as the wild-type rIHNV in cell culture. This study was extended by exchanging IHNV G with that of a fish vesiculovirus able to replicate at high temperatures (up to 28°C), the spring viremia of carp virus (SVCV). rIHNV-Gsvcv was successfully recovered; however, its growth was restricted to 14 to 20°C. These results show the nonspecific sequence requirement for the insertion of heterologous glycoproteins into IHNV virions and also demonstrate that an IHNV protein other than the G protein is responsible for the low-temperature restriction on growth. To determine to what extent the matrix (M) protein interacts with G, a series of chimeric pIHNV constructs in which all or part of the M gene was replaced with the VHSV counterpart was engineered and used to recover the respective recombinant viruses. Despite the very low percentage (38%) of amino acid identity between the IHNV and VHSV matrix proteins, viable chimeric IHNVs, harboring either the matrix protein or both the glycoprotein and the matrix protein from VHSV, were recovered and propagated. Altogether, these data show the extreme flexibility of IHNV to accommodate heterologous structural proteins