The rabies virus glycoprotein ectodomain determines the activation of dendritic cells (2023)

Rabies, caused by the rabies virus (RABV), is an ancient zoonotic disease that poses a serious threat to public health worldwide. Previous studies showed that interleukin-1β (IL-1β) plays an important role in RABV infection. However, the mechanism by which IL-1β influences the pathogenicity of RABV is still unknown. In this study, we confirmed that IL-1β is able to reduce RABV virus titers in different cells and that recombinant RABV expressing IL-1β, called rCVS-IL1β, can be reduced in different cells due to IL-1β expression. are suppressed. In addition, the survival rates of mice infected intramuscularly with rCVS-IL1β were significantly higher than those of mice infected with the native rCVS virus, which is associated with a lower viral load upon entry into the central nervous system (CNS). Furthermore, we characterized that the cGAS-STING pathway was activated in rCVS-IL1β-infected bone marrow-derived dendritic cells (BMDCs), which may contribute to reduced RABV viral load following intramuscular infection. In addition, we also observed that IL-1β expression by rCVS-IL1β could compromise blood-brain barrier (BBB) ​​integrity by degrading tight junction proteins, leading to peripheral inflammatory cytokines, chemokines and CD4 cells are enabled .⁺T cells invade the brain to clear RABV in the CNS. Overall, our study suggests that IL-1β could attenuate RABV pathogenicity by activating the cGAS-STING pathway to decrease viral entry into the CNS and increase BBB permeability to also increase CNS clearance or to promote RABV. This offers a new perspective on the development of effective rabies therapies.

Rabies remains a major public health threat in most developing countries. To develop a more effective and safer oral rabies vaccine, we are developing recombinant vaccinesLactobacillus plantsNC8 carries one or two copies of the G gene with a dendritic cell targeting peptide (DCpep) fused to the C-terminus, designated as NC8-pSIP409-sRVG and NC8-pSIP409-dRVG, respectively. The immunogenicity and protective effect of these recombinantsLactobacillus plantsagainst RABV were evaluated by oral administration in a mouse model. The results showed that recombinant NC8-pSIP409-dRVG possessed more G protein, resulting in more functional DC maturation. After three cycles of oral immunization, NC8-pSIP409-dRVG induced significantly higher levels of specific IgG antibodies and mixed Th1/Th2 with a strong Th1-sesd immune response in mice. Most importantly, NC8-pSIP409-dRVG was able to protect 60% of vaccinated mice against the lethal challenge of RABV, despite RABV neutralizing antibody titers (NAV) being below the threshold of 0.5 IU/ml. RABV. These data indicate that recombinant NC8-pSIP409-dRVG could be a promising new oral vaccine for the prevention and control of rabies in animals.

Connectomics studies have gone "viral" because viral pathogens have become irreplaceable neuroscience research tools. Highly sensitive viral transneuronal screening technologies are available based on the use of alpha-herpesviruses and a rhabdovirus (rabies virus) that act as self-amplifying markers by replicating in recipient neurons. These viruses vary greatly in terms of host range, cellular receptors, peripheral uptake, replication, direction of transport and specificity. Their properties that make them useful for various purposes are highlighted and contrasted. Only transneuronal screening with rabies virus is completely specific. The neuroscientists' toolbox currently includes wild-type alpha-herpesvirus and rabies virus strains that enable polysynaptic scanning of neuronal networks across multiple synapses, as well as genetically engineered viral tracers for dual transneuronal scanning and viral tools. Complementary cells include defective and chimeric recombinants that function as single monosynaptically restricted or cascaded tracers or serve to control and manipulate neuronal activity and gene expression. Methodological issues critical to the proper use of these technologies are summarized. Of the wild-type and genetically engineered viral tools, the rabies virus and rabies virus-based chimeric recombinants are the most powerful as viral backbones, as the rabies virus can only spread between neurons that are connected in a unidirectional (retrograde) manner without compromising neural function . A thorough understanding of viral properties is essential for neuroscientists who wish to use alpha-herpesviruses, rhabdoviruses or derived recombinants as research tools. Key insights into their cellular receptors, intracellular trafficking, and contrasting host defense strategies that explain their distinct pathophysiology and properties as research tools are summarized.

Microbes and Infections, Volume 19, Numeri 9 en 10, 2017, pp. 485-491

Rabies is a deadly zoonosis and infections generally lead to fatal encephalomyelitis in both humans and animals. In South Africa, native (dog) and wild (yellow mongoose) host species maintain the canid and mongoose varieties of rabies, respectively. In this study, differences in the pathogenicity of South African canine and mongoose rabies viruses were investigated in a mouse model by assessing clinical symptom progression and survival. Comparison of the glycoprotein gene sequences revealed amino acid differences that may support the observed differences in pathogenicity. Overall, our results suggest that rabies virus may be more neurovirulent than the mongoose rabies variant in mice.

Current Opinion in Virology, Volume 28, 2018, pages 68-73

Lyssaviruses are a broad spectrum of viruses that cause rabies disease. Of the 16 recognized species, only rabies virus (RABV) has multiple host reservoirs. While lyssaviruses can infect all mammals, subsequent transmission to a new host population requires the virus to adapt in a series of steps, with both host and viral factors determining the outcome. Since there are no recorded changes in non-RABV hosts, the RABV data are extrapolated to draw conclusions for all lyssaviruses. In this article, we focused on the evidence for host switching in the same reservoir species of insectivorous bats in North America (RABV) and Europe (EBLV-1, EBLV-2 and BBLV). In this review, we examine how RABV has managed to overcome species barriers and establish infection cycles in novel hosts to become the global multihost pathogen it is today, while other lyssaviruses appear to be host-restricted. He hypothesized that RABV was the exception rather than the rule in this fascinating genus of viruses.

Vaccine, Volume 35, Issue 42, 2017, pp. 5622-5628

The current live rabies vaccine SAG2 is attenuated by a single mutation (Arg-a-Glu) at position 333 of the glycoprotein (G333). This fact carries the potential risk of emergence of a recurrent pathogen due to retromutation at this position during viral replication in the organism. To avoid this risk, it is desirable to create a live vaccine strain that is highly attenuated by multiple mutations and stable. However, there is very limited information on attenuating mutations other than that of G333. We previously reported that amino acids at positions 273 and 394 in the nucleoprotein (N273/394) (Leu and His, respectively) of Ni-CE-fixed rabies virus are responsible for the attenuated phenotype by enhancing interferon (IFN) gene expression. /Chemokines in infected nerve cells. In this study, we found that amino acid substitutions at N273/394 (Phe-to-Leu and Tyr-to-His, respectively) attenuated the pathogenicity of the live oral vaccine ERA, which has a virulent type of Arg at G333. We then generated attenuated ERA-N273/394-G333 by combining the above attenuating mutations in G333 and N273/394 and verified its safety. Like ERA-G333, which is only attenuated by mutation in G333, ERA-N273/394-G333 caused no symptoms in adult mice after intracerebral inoculation, indicating low residual pathogenicity of ERA-N273. /394-G333 . Further investigation showed that infection with ERA-N273/394 induces G333IFN-βJCXCL10Higher mRNA expression than ERA-G333 infection in a neuroblastoma cell line. Importantly, we found that ERA-N273/394-G333 staining has a lower risk of pathogen reversal than ERA-G333. These results suggest that ERA-N273/394-G333 has the potential to be a promising candidate for a live rabies vaccine strain with a high level of safety.

Virus Research, Volume 220, 2016, pp. 161-171

The glycoprotein (G) is the only surface protein of the lyssavirus particle and the only viral product known to trigger the production of neutralizing antibodies. In this study, an attempt was made to isolate escape mutants resistant to neutralization of monoclonal antibody (Mabs) using a selection strategy using four different strains of the rabies virus: the widely distributed strain Evelyn Rokitnicki Abelseth (ERA) and three field isolates, the two Bat-associated variants and the Western Canadian Skunk variant (WSKV). Escape mutants were not generated from any of the bat-associated virus variants, but two neutralizing mutants were derived from the WSKV isolate. Seven independent ERA mutants were generated using Mabs directed against antigenic sites I (four mutants) and IIIa (three mutants) of the glycoprotein. The cross-neutralization patterns of these mutant viruses were used to determine the precise location and nature of the G protein epitopes recognized by these Mabs. Nucleotide sequencing of the G gene showed that all mutants derived using Mabs targeting the antigenic site (AA) III contained amino acid substitutions at this site. However, of the four mutants selected with AS I Mabs, two carried mutations within AS I, while the remaining two carried mutations within AS II, as expected. WSKV mutants showed mutations at the correct sites for the Mabs used in their selection. All ERA mutant preparations were more cytopathogenic than the parent virus when propagated in cell culture; IfliveWhen pathogenicity was examined in mice, three of these mutants showed reduced pathogenicity, while the remaining four mutants showed pathogenic properties similar to those of the parent virus.

Antiviral Research, Volume 121, 2015, pp. 9-15

Oral vaccination of stray dogs is one of the most practical ways to prevent rabies in developing countries. The safe, effective and long-lasting protective oral rabies vaccine for dogs is in high demand. In this study, the rabies virus (RABV) strain Evelyn-Rokitnicki-Abelseth (ERA) was a wild type (rERA) and a genetically modified type (rERAG)._333E), which contains a mutation from arginine to glutamic acid at residue 333 of the glycoprotein (G_333E) were created through reverse genetics. recombinant rERAG virus_333Eretained growth characteristics similar to the parent strain rERA in BHK-21 cell culture. the G_333EThe mutation showed genetic stability during passage in neuroblastoma cells and in the brains of lactating mice and significantly reduced the virulence of rERA in mice. REAG_333EIt was immunogenic in dogs by intramuscular inoculation. Mice vaccinated orally with rERAG_333EThey induced potent virus neutralizing antibodies (VNA) against RABV for one year and were completely protected against exposure to the deadly street virus 12 months after immunization. Dogs received an oral vaccination with rERAG_333Eelicited a strong protective VNA response against rabies virus that persisted for more than three years and moderate salivary rabies virus-specific IgA. In addition, significant booster responses to RABV VNA were induced by a second oral dose one year after the first dose. These results demonstrated that the genetically engineered ERA vaccine strain has the potential to serve as a safe and effective live oral vaccine against rabies in dogs.

Vaccine, Volume 39, Issue 28, 2021, pp. 3777-3784

To improve the safety of live genetically modified rabies vaccine strains, most studies have used an attenuating mutation from Arg to Glu at position 333 of the glycoprotein (G333), which is responsible for attenuating the vaccine strain. Long live SAG2. The Glu residue requires two nucleotide substitutions to be converted to pathogenic Arg, greatly reducing the likelihood of pathogenic reversal caused by the Glu-to-Arg mutation in G333. However, only one nucleotide change is sufficient to convert the Glu residue to another pathogenic residue, Lys, and thus induce pathogenic reversion. This indicates a potential safety issue of the SAG2 and Glu-live attenuated vaccine candidates in G333. To solve this problem, in this study we investigated the utility of a Leu residue, which requires two nucleotide substitutions to be both Arg and Lys, as an attenuating mutation in G333. Using a reverse genetic system of the live ERA vaccine strain, we generated ERA-G333Leu by introducing an Arg to Leu mutation in G333. Like ERA-G333Glu, which is attenuated by an Arg-to-Glu mutation in G333, ERA-G333Leu caused no obvious clinical signs in 6-week-old mice after intracerebral inoculation. Importantly, after 10 passages in the brains of lactating mice, ERA-G333Glu acquired a pathogenic Lys or Arg in G333 and a high level of mouse lethality, while ERA-G333Leu retained the Leu quencher in G333 and probably only a moderate level of virulence. showed. caused by a mutation in G194. In addition, ERA-G333Leu and ERA-G333Glu induced a neutralizing antibody response and protective immunity in mice with similar potency. The results show that ERA-G333Leu is more stably attenuated compared to ERA-G333Glu, also pointing to the great utility of a Leu residue as an attenuating mutation in G333 in the development of live rabies vaccine strains with a high level of safety.