Establishment of a longitudinal pre-clinical model of lyssavirus infection.

Traditional mouse models of lyssavirus pathogenesis rely on euthanizing large groups of animals at various time points post-infection, processing infected tissues, and performing histological and molecular analyses to determine anatomical sites of infection. While powerful by some measures, this approach is limited by the inability to monitor disease progression in the same mice over time. In this study, we established a novel non-invasive mouse model of lyssavirus pathogenesis, which consists of longitudinal imaging of a luciferase-expressing Australian bat lyssavirus (ABLV) reporter virus. In vivo bioluminescence imaging (BLI) in mice revealed viral spread from a peripheral site of inoculation into the central nervous system (CNS), with kinetically and spatially distinct foci of replication in the footpad, spinal cord, and hindbrain. Detection of virus within the CNS was associated with onset of clinical disease. Quantification of virus-derived luminescent signal in the brain was found to be a reliable measure of viral replication, when compared to traditional molecular methods. Furthermore, we demonstrate that in vivo imaging of ABLV infection is not restricted to the use of albino strains of mice, but rather strong BLI signal output can be achieved by shaving the hair from the heads and spines of pigmented strains, such as C57BL/6. Overall, our data show that in vivo BLI can be used to rapidly and non-invasively identify sites of lyssavirus replication and to semi-quantitatively determine viral load without the need to sacrifice mice at multiple time points.

The LC8-RavP ensemble Structure Evinces A Role for LC8 in Regulating Lyssavirus Polymerase Functionality.

The rabies and Ebola viruses recruit the highly conserved host protein LC8 for their own reproductive success. In vivo knockouts of the LC8 recognition motif within the rabies virus phosphoprotein (RavP) result in completely nonlethal viral infections. In this work, we examine the molecular role LC8 plays in viral lethality. We show that RavP and LC8 colocalize in rabies infected cells, and that LC8 interactions are essential for efficient viral polymerase functionality. NMR, SAXS, and molecular modeling demonstrate that LC8 binding to a disordered linker adjacent to an endogenous dimerization domain results in restrictions in RavP domain orientations. The resulting ensemble structure of RavP-LC8 tetrameric complex is similar to that of a related virus phosphoprotein that does not bind LC8, suggesting that with RavP, LC8 binding acts as a switch to induce a more active conformation. The high conservation of the LC8 motif in Lyssavirus phosphoproteins and its presence in other analogous proteins such as the Ebola virus VP35 evinces a broader purpose for LC8 in regulating downstream phosphoprotein functions vital for viral replication.

[Construction of a Recombinant Replication-defective Human Adenovirus Type 5 Expressing G Protein of Irkut Virus and the Immune Test in Mouse].

To develop a safe and effective new generation vaccine for IRKV-THChina12 prevention, we constructed a non-replicative recombinant human adenovirus carrying the IRKV-THChina12 G gene, named as rAd5-IRKV-G. The IRKV-THChina12 G protein expressed by the recombinant human adenovirus in 293AD cells was detected by western blot and indirect immunofluorescence test. To evaluate the immunogenicity of the recombinant, mice were immunized with rAd5-IRKV-G by intramuscular (i. m.) or intraperitoneal (i. p.) route and with non-exogenous gene expressing wild type adenovirus wt-rAd5 as a control. Results showed that the rAd5-IRKV-G could induce continuous and statistically significant (P ≤ 0.05) anti-IRKV neutralizing antibody (NA) production in immunized mice by i. m. or i. p. route. In particular, no significant difference (P > 0.05) of the NA titers between the two administration routes were observed, that provides an alternative choice for animal immunization method in the future application.

The complete Mokola virus genome sequence: structure of the RNA-dependent RNA polymerase.

The genome sequence of the rabies-related virus Mokola virus (genus Lyssavirus) has been completed by sequencing the L gene, which consists of 6384 nucleotides encoding a 2127 amino acid polymerase. Alignment of the Mokola virus L protein with other polymerases from the virus order Mononegavirales defined three domains: a divergent NH2-terminal domain, a highly conserved central domain carrying most of the functional motifs and a COOH-terminal domain with alternating conserved and divergent regions. A statistical study outlined the stringency of conservation of glycine, acidic (D, E) and basic (K, R, H) amino acids in polymerases, particularly as key residues of the conserved motifs.