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Emerging Microbes & Infections Dec 2023Marburg virus disease (MVD) is a lethal viral haemorrhagic fever caused by Marburg virus (MARV) with a case fatality rate as high as 88%. There is currently no vaccine...
Marburg virus disease (MVD) is a lethal viral haemorrhagic fever caused by Marburg virus (MARV) with a case fatality rate as high as 88%. There is currently no vaccine or antiviral therapy approved for MVD. Due to high variation among MARV isolates, vaccines developed against one strain fail to protect against other strains. Here we report that three recombinant rabies virus (RABV) vector vaccines encoding two copies of GPs covering both MARV lineages induced pseudovirus neutralizing antibodies in BALB/c mice. Furthermore, high-affinity human neutralizing antibodies were isolated from a humanized mouse model. The three vaccines produced a Th1-biased serological response similar to that of human patients. Adequate sequential immunization enhanced the production of neutralizing antibodies. Virtual docking suggested that neutralizing antibodies induced by the Angola strain seemed to be able to hydrogen bond to the receptor-binding site (RBS) in the GP of the Ravn strain through hypervariable regions 2 (CDR2) and CDR3 of the VH region. These findings demonstrate that three inactivated vaccines are promising candidates against different strains of MARV, and a novel fully humanized neutralizing antibody against MARV was isolated.
Topics: Humans; Animals; Mice; Marburgvirus; Antibodies, Neutralizing; Rabies virus; Antibodies, Viral; Glycoproteins; Marburg Virus Disease; Viral Vaccines
PubMed: 36453198
DOI: 10.1080/22221751.2022.2149351 -
Open Veterinary Journal Sep 2023Neurotropic viruses in the family Rhabdoviridae, genus , are what cause rabies, an acute, progressive, and highly lethal encephalomyelitis.
BACKGROUND
Neurotropic viruses in the family Rhabdoviridae, genus , are what cause rabies, an acute, progressive, and highly lethal encephalomyelitis.
AIM
Evaluation of the used diagnostic techniques to determine the most simple; rapid and accurate test for rabies virus (RABV) recognition in different specimens aiming to reach a rapid diagnosis as a step aid in the disease control and to prevent or even minimize the suspected hazard.
METHOD
The used techniques included an infection trial of Swiss mice with the mice-adapted challenge rabies virus followed by the detection of the virus in the infected mices' brains. Virus detection was carried out through the application BHK21 cell line infection; fluorescent antibody technique; latex agglutination test (LAT); direct enzyme-linked immunosorbent assay (ELISA); rabies antigen detection kit ELISA; conventional polymerase chain reaction (PCR).
RESULTS
It was found that virus inoculation in mice and BHK21 cell lines needs 5-7 days with positivity of 90% and 100%, respectively. Rapid antigen kit was able to detect rabies antigen in mice brains suspension and BHK21 infected fluid within 3-5 minutes with percentages of 60% and 55.5%, respectively. In 1-1.5 hours, the direct fluorescent antibody method (DFAT) detected 90% and 100% of the rabies antigen in BHK21 cell line infection and brain impressions, respectively. Latex agglutination showed clear results with 88.8% with BHK21 infected fluid within 3-5 minutes while it did not carry out on brain emulsions to prevent falsely positive results brought on by the presence of tissue fragments. Conventional one-step PCR revealed 100% positivity with either brain or cell culture preparations within 2 days. Direct ELISA showed 88.8% positivity with BHK21 infected fluid with 1 day of work.
CONCLUSION
Mice inoculation test, cell culture infection; DFAT and PCR are the most accurate techniques for the detection of RABV with a positivity of 90%-100% followed by LAT and ELISA with a positivity of 88.8%, and lastly, rabies antigen ELISA kit (RAK) with a positivity of 55.5%-60% taking in consideration the required time for each. In addition, the positivity % of the applied tests revealed their sensitivity and specificity.
Topics: Animals; Mice; Rabies virus; Rabies; Lyssavirus; Sensitivity and Specificity; Cell Culture Techniques
PubMed: 37842113
DOI: 10.5455/OVJ.2023.v13.i9.13 -
Pathogens (Basel, Switzerland) Apr 2024Rabies, one of the most lethal global zoonoses, affects all mammals. It remains circulating worldwide in sylvatic cycles through terrestrial and airborne reservoirs, and...
Rabies, one of the most lethal global zoonoses, affects all mammals. It remains circulating worldwide in sylvatic cycles through terrestrial and airborne reservoirs, and in Brazil, bats are currently the main reservoirs and source of transmission. Wild boars, an important invasive alien species in Brazil, are a proven food source for hematophagous bats and may participate in the Brazilian sylvatic cycle of rabies. We evaluated the presence of this pathogen in hunted wild boars from the São Paulo state using histopathology, the direct fluorescent antibody test (DFA), viral isolation in cell culture (VICC), the rapid fluorescent focus inhibition test (RFFIT), and quantitative reverse transcription polymerase chain reaction (RT-qPCR). The results of histopathological, DFA, VICC, and RT-qPCR analysis were negative for all samples; seven serum samples tested positive in the RFFIT, and titers ranged from 0.13 IU/mL to 0.5 IU/mL. The presence of rabies virus-neutralizing antibodies in the studied wild boars suggests the circulation of the virus in these animals. Educative actions directed at hunters should include information on the prevention of this important zoonosis.
PubMed: 38668258
DOI: 10.3390/pathogens13040303 -
Viruses Jul 2023Rabies virus (RABV) causes possibly the oldest disease and is responsible for an estimated >59,000 human fatalities/year. Post exposure prophylaxis (PEP), the...
Rabies virus (RABV) causes possibly the oldest disease and is responsible for an estimated >59,000 human fatalities/year. Post exposure prophylaxis (PEP), the administration of vaccine and rabies immunoglobulin, is a highly effective tool which is frequently unavailable in RABV endemic areas. Furthermore, due to the constraints of the blood-brain barrier, current PEP regimes are ineffective after the onset of clinical symptoms which invariably result in death. To circumvent this barrier, a live-attenuated recombinant RABV expressing a highly RABV-neutralising scFv antibody (62-71-3) linked to the fluorescent marker mCherry was designed. Once rescued, the resulting construct (named RABV-62scFv) was grown to high titres, its growth and cellular dissemination kinetics characterised, and the functionality of the recombinant 62-71-3 scFv assessed. Encouraging scFv production and subsequent virus neutralisation results demonstrate the potential for development of a therapeutic live-attenuated virus-based post-infection treatment (PIT) for RABV infection.
Topics: Humans; Rabies; Rabies virus; Rabies Vaccines; Antibodies; Biological Transport
PubMed: 37632016
DOI: 10.3390/v15081674 -
Brain Research Bulletin Sep 2023The nucleus tractus solitarii (NTS) is the primary central station that integrates visceral afferent information and regulates respiratory, gastrointestinal,...
The nucleus tractus solitarii (NTS) is the primary central station that integrates visceral afferent information and regulates respiratory, gastrointestinal, cardiovascular, and other physiological functions. Leptin receptor b (LepRb)-expressing neurons of the NTS (NTS neurons) are implicated in central respiration regulation, respiratory facilitation, and respiratory drive enhancement. Furthermore, LepRb dysfunction is involved in obesity, insulin resistance, and sleep-disordered breathing. However, the monosynaptic inputs and outputs of NTS neurons in whole-brain mapping remain to be elucidated. Therefore, the exploration of its whole-brain connection system may provide strong support for comprehensively understanding the physiological and pathological functions of NTS neurons. In the present study, we used a cell type-specific, modified rabies virus and adeno-associated virus with the Cre-loxp system to map monosynaptic inputs and outputs of NTS neurons in LepRb-Cre mice. The results showed that NTS neurons received inputs from 48 nuclei in the whole brain from five brain regions, including especially the medulla. We found that NTS neurons received inputs from nuclei associated with respiration, such as the pre-Bötzinger complex, ambiguus nucleus, and parabrachial nucleus. Interestingly, some brain areas related to cardiovascular regulation-i.e., the ventrolateral periaqueductal gray and locus coeruleus-also sent a small number of inputs to NTS neurons. In addition, anterograde tracing results demonstrated that NTS neurons sent efferent projections to 15 nuclei, including the dorsomedial hypothalamic nucleus and arcuate hypothalamic nucleus, which are involved in regulation of energy metabolism and feeding behaviors. Quantitative statistical analysis revealed that the inputs of the whole brain to NTS neurons were significantly greater than the outputs. Our study comprehensively revealed neuronal connections of NTS neurons in the whole brain and provided a neuroanatomical basis for further research on physiological and pathological functions of NTS neurons.
Topics: Mice; Animals; Solitary Nucleus; Receptors, Leptin; Neurons; Brain Mapping; Obesity
PubMed: 37348822
DOI: 10.1016/j.brainresbull.2023.110693 -
Human Vaccines & Immunotherapeutics Dec 2023A serum-free, highly purified rabies vaccine produced in Vero cells is under development. The initial formulation, PVRV-NG, was evaluated in five Phase II studies and... (Randomized Controlled Trial)
Randomized Controlled Trial
Safety and immunogenicity of three dose levels of an investigational, highly purified Vero cell rabies vaccine: A randomized, controlled, observer-blinded, Phase II study with a simulated post-exposure regimen in healthy adults.
A serum-free, highly purified rabies vaccine produced in Vero cells is under development. The initial formulation, PVRV-NG, was evaluated in five Phase II studies and subsequently reformulated (PVRV-NG2). This multicenter, observer-blinded Phase II study investigated the safety and immune response of three different doses (antigen content) of PVRV-NG2 versus a licensed human diploid cell rabies vaccine (HDCV; Imovax rabies®). Healthy adults ( = 320) were randomized to receive PVRV-NG2 (low, medium, or high dose), PVRV-NG, or HDCV (2:2:2:1:1 ratio), according to a five-dose Essen simulated post-exposure regimen (Days [D] 0, 3, 7, 14, and 28). All participants received human rabies immunoglobulin intramuscularly on D0. Immunogenicity was assessed at D0, 14, 28, 42, and 6 months after the final injection using the rapid fluorescent focus inhibition test. Seroconversion rates were calculated as the percentage of participants achieving rabies virus neutralizing antibody titers ≥0.5 IU/mL. All analyses were descriptive. At each timepoint, geometric mean titers (GMTs) increased with antigen content (measured using an enzyme-linked immunosorbent assay). High-dose PVRV-NG2 GMTs were the highest at all timepoints, medium-dose PVRV-NG2 GMTs were similar to those with HDCV, and low-dose PVRV-NG2 GMTs were similar to PVRV-NG. The safety profile of PVRV-NG2 was comparable to PVRV-NG; however, fewer injection site reactions were reported with PVRV-NG2 or PVRV-NG (range 36.7-47.5%) than with HDCV (61.5%). This study demonstrated a dose-effect of antigen content at all timepoints. As post-exposure prophylaxis, the safety and immunogenicity profiles of the high-dose PVRV-NG2 group compared favorably with HDCV. Clinicaltrials.gov number: NCT03145766.
Topics: Animals; Chlorocebus aethiops; Humans; Adult; Rabies Vaccines; Rabies; Vero Cells; Rabies virus; Antibodies, Viral
PubMed: 37921410
DOI: 10.1080/21645515.2023.2275453 -
Journal of Virological Methods Sep 2023Rabies virus (RABV) causes a fatal encephalitis that can be prevented through timely vaccination. The levels of virus neutralising antibodies against rabies virus...
Rabies virus (RABV) causes a fatal encephalitis that can be prevented through timely vaccination. The levels of virus neutralising antibodies against rabies virus induced by vaccination can be measured using the fluorescent antibody virus neutralisation (FAVN) test. Following incubation of live virus with sera, this method involves the fixation of cell monolayers and staining of rabies virus-specific antigen using fluorescein isothiocyanate (FITC) -conjugated antibody to enable visualisation of rabies virus antigen using a fluorescence microscope. To simplify this procedure, a fluorescent recombinant rabies virus was constructed using reverse genetics by inserting the gene for the mCherry fluorescent protein in front of the ribonucleoprotein gene of the SAD B-19 genome and replacing its glycoprotein with that of the Challenge Virus Standard (CVS)-11 RABV strain to ensure antigenic authenticity with the FAVN. This new recombinant virus (termed mCCCG) expressed the mCherry protein to high levels enabling direct observation of infected cells. In vitro growth kinetics of mCCCG were indistinguishable from that of CVS-11. The stability of the recombinant virus was assessed by sequencing several passages of the rescued virus and only minor changes were detected. Comparative assessment of the virus neutralisation test using mCherry producing virus (NTmCV) against the FAVN demonstrated that test results were equivalent to each other; therefore, mCCCG can be used as an alternative to CVS-11 for measuring antibody titres against the rabies virus. The use of NTmCV removes the need for expensive antibody conjugates and significantly reduces assay time. This would be particularly beneficial for RABV serological assessment in resource limited settings. Moreover, the reading of the plates can be automatically using a cell imaging reader.
Topics: Humans; Rabies virus; Antibodies, Viral; Neutralization Tests; Rabies; Antigens, Viral; Antibodies, Neutralizing; Rabies Vaccines
PubMed: 37391076
DOI: 10.1016/j.jviromet.2023.114769 -
Frontiers in Veterinary Science 2023Rabies is endemic in Madagascar and a neglected disease. The aim of this study was to summarize human and animal rabies surveillance activities in Madagascar from 2011...
Rabies is endemic in Madagascar and a neglected disease. The aim of this study was to summarize human and animal rabies surveillance activities in Madagascar from 2011 to 2021. Samples from terrestrial mammals and humans were tested for rabies virus infection using direct fluorescent antibody, RT-PCR and virus isolation by the National Reference Laboratory (NRL) for rabies at the Institut Pasteur de Madagascar. Among 964 animal and 47 human samples tested, 66.7 and 70.2% were positive, respectively. The NRL received these suspect rabies samples from 48 of 114 districts of Madagascar. Most of them were submitted from the district of the capital city Antananarivo (26.3%) and mainly from its region Analamanga (68.9%). Animal samples were mainly from dogs (83%), cats (9.5%) and cattle (5.8%). Pigs, lemurs, goats accounted for less than 1%. During the 11 years of surveillance, 48 human skin and/or brain biopsy samples were received from 20 districts, mainly from Antananarivo and its surroundings ( = 13), Toamasina and its surroundings ( = 8) and Moramanga ( = 6). The high positivity rate for all species and the non-homogeneous spatial distribution of samples suggests substantial underreporting of rabies cases. There is a clear need to better understand the reasons for underreporting and prioritize rabies surveillance, prevention and control in Madagascar, with improvements in budget, education and infrastructure. A joint animal and human health rabies control program including vaccination of at least 70% of the dog population, is needed to achieve the goal of eliminating dog-transmitted human rabies by 2030 from Madagascar.
PubMed: 37901098
DOI: 10.3389/fvets.2023.1270532 -
Stem Cell Reports Dec 2023Although adult subependymal zone (SEZ) neural stem cells mostly generate GABAergic interneurons, a small progenitor population expresses the proneural gene Neurog2 and...
Although adult subependymal zone (SEZ) neural stem cells mostly generate GABAergic interneurons, a small progenitor population expresses the proneural gene Neurog2 and produces glutamatergic neurons. Here, we determined whether Neurog2 could respecify SEZ neural stem cells and their progeny toward a glutamatergic fate. Retrovirus-mediated expression of Neurog2 induced the glutamatergic lineage markers TBR2 and TBR1 in cultured SEZ progenitors, which differentiated into functional glutamatergic neurons. Likewise, Neurog2-transduced SEZ progenitors acquired glutamatergic neuron hallmarks in vivo. Intriguingly, they failed to migrate toward the olfactory bulb and instead differentiated within the SEZ or the adjacent striatum, where they received connections from local neurons, as indicated by rabies virus-mediated monosynaptic tracing. In contrast, lentivirus-mediated expression of Neurog2 failed to reprogram early SEZ neurons, which maintained GABAergic identity and migrated to the olfactory bulb. Our data show that NEUROG2 can program SEZ progenitors toward a glutamatergic identity but fails to reprogram their neuronal progeny.
Topics: Basic Helix-Loop-Helix Transcription Factors; Neurons; Neural Stem Cells; Cell Differentiation; Olfactory Bulb; Neurogenesis
PubMed: 37995703
DOI: 10.1016/j.stemcr.2023.10.019 -
Revista Da Sociedade Brasileira de... 2024Human Rabies (HR) is a fatal zoonotic disease caused by lyssaviruses, with the rabies virus (RABV) identified as the causative agent. While the incidence of HR... (Review)
Review
Human Rabies (HR) is a fatal zoonotic disease caused by lyssaviruses, with the rabies virus (RABV) identified as the causative agent. While the incidence of HR transmitted by dogs has decreased in Latin America, there has been a corresponding rise in transmission via wild animals. Given the lack of effective treatments and specific therapies, the management of HR relies on the availability of post-exposure prophylaxis and animal control measures. This review examines the dynamics and spread of HR during the global pandemic.
Topics: Humans; Animals; Dogs; Rabies; Pandemics; Brazil; COVID-19; Rabies virus
PubMed: 38359308
DOI: 10.1590/0037-8682-0520-2023