The cytoplasmic tail of the rabies virus G protein is an essential domain controlling death/survival in human neuronal cells

Poster presentation

In vitro and in vivo evaluation of a single chain antibody fragment generated in planta with potent rabies neutralisation activity.

Rabies causes more than 60,000 human deaths annually in areas where the virus is endemic. Importantly, rabies is one of the few pathogens for which there is no treatment following the onset of clinical disease with the outcome of infection being death in almost 100% of cases. Whilst vaccination, and the combination of vaccine and rabies immunoglobulin treatment for post-exposure administration are available, no tools have been identified that can reduce or prevent rabies virus replication once clinical disease has initiated. The search for effective antiviral molecules to treat those that have already developed clinical disease associated with rabies virus infection is considered one of the most important goals in rabies research. The current study assesses a single chain antibody molecule (ScFv) based on a monoclonal antibody that potently neutralises rabies in vitro as a potential therapeutic candidate. The recombinant ScFv was generated in Nicotiana benthamiana by transient expression, and was chemically conjugated (ScFv/RVG) to a 29 amino acid peptide, specific for nicotinic acetylcholine receptor (nAchR) binding in the CNS. This conjugated molecule was able to bind nAchR in vitro and enter neuronal cells more efficiently than ScFv. The ability of the ScFv/RVG to neutralise virus in vivo was assessed using a staggered administration where the molecule was inoculated either four hours before, two days after or four days after infection. The ScFv/RVG conjugate was evaluated in direct comparison with HRIG and a potential antiviral molecule, Favipiravir (also known as T-705) to indicate whether there was greater bioavailability of the ScFv in the brains of treated mice. The study indicated that the approach taken with the ScFv/RVG conjugate may have utility in the design and implementation of novel tools targetting rabies virus infection in the brain

Toll-Like Receptor 3 (TLR3) Plays a Major Role in the Formation of Rabies Virus Negri Bodies

Human neurons express the innate immune response receptor, Toll-like receptor 3 (TLR3). TLR3 levels are increased in pathological conditions such as brain virus infection. Here, we further investigated the production, cellular localisation, and function of neuronal TLR3 during neuronotropic rabies virus (RABV) infection in human neuronal cells. Following RABV infection, TLR3 is not only present in endosomes, as observed in the absence of infection, but also in detergent-resistant perinuclear inclusion bodies. As well as TLR3, these inclusion bodies contain the viral genome and viral proteins (N and P, but not G). The size and composition of inclusion bodies and the absence of a surrounding membrane, as shown by electron microscopy, suggest they correspond to the previously described Negri Bodies (NBs). NBs are not formed in the absence of TLR3, and TLR3−/− mice—in which brain tissue was less severely infected—had a better survival rate than WT mice. These observations demonstrate that TLR3 is a major molecule involved in the spatial arrangement of RABV–induced NBs and viral replication. This study shows how viruses can exploit cellular proteins and compartmentalisation for their own benefit

Etude genetique et moleculaire de la glycoproteine du virus rabique CVS

CNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

Role of the glycoprotein thorns in anxious effects of rabies virus: Evidence from an animal study

International audienceRabies is a lethal infectious disease caused by rabies virus (RABV). Fear and anxiety are the distinguished symptoms in rabies patients. Fusion of RABV envelope glycoprotein (RVG) to host cell membrane initiates rabies pathogenesis via interacting with PDZ domain of signaling proteins. We assessed the anxiety-like behaviors, and hypothalamic-pituitary-adrenal axis (HPA) response to RVG infection. Contribution of PDZ binding motif (PBM) of RVG to the observed effects was also examined using a mutant form of RVG, ΔRVG, with deleted last four amino acids at PBM C-terminus. Lentiviral vectors containing RVG and/or ΔRVG genes were injected into the rat brain areas involved in anxiety including hypothalamus, dorsal hippocampus, and amygdala. RVG/ΔRVG neural expression was examined by fluorescent microscopy. Anxiety-like behaviors were assessed by elevated plus maze (EPM) and open field (OF) tasks. HPA response was evaluated via measuring corticosterone serum level by ELISA technique. RVG/ΔRVG were successfully expressed in neurons of the injected areas. RVG, but not ΔRVG, infection of hypothalamus and amygdala increased the time spent in EPM open arms, and OF total distance moved and velocity. RVG, but not ΔRVG, infection of hypothalamus and dorsal hippocampus increased corticosterone level. The anxiety-like behaviors and exploratory/locomotor activities of rats with RVG infection in hypothalamus, and amygdala are mediated by PBM of RVG. The HPA response to RVG infection of hypothalamus and dorsal hippocampus is dependent to PBM of RVG. Triggering anxiety-related signaling by PBM of RVG seems to be one of the mechanisms involved in anxiety behaviors seen in patients with rabies