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Communications Biology Mar 2024
PubMed: 38429356
DOI: 10.1038/s42003-024-05963-7 -
Applied Microbiology and Biotechnology Feb 2024Flavivirus virus-like particles (VLPs) exhibit a striking structural resemblance to viral particles, making them highly adaptable for various applications, including...
Flavivirus virus-like particles (VLPs) exhibit a striking structural resemblance to viral particles, making them highly adaptable for various applications, including vaccines and diagnostics. Consequently, increasing VLPs production is important and can be achieved by optimizing expression plasmids and cell culture conditions. While attempting to express genotype III (GIII) Japanese encephalitis virus (JEV) VLPs containing the G104H mutation in the envelope (E) protein, we failed to generate VLPs in COS-1 cells. However, VLPs production was restored by cultivating plasmid-transfected cells at a lower temperature, specifically 28 °C. Furthermore, we observed that the enhancement in JEV VLPs production was independent of amino acid mutations in the E protein. The optimal condition for JEV VLPs production in plasmid-transfected COS-1 cells consisted of an initial culture at 37 °C for 6 h, followed by a shift to 28 °C (37/28 °C) for cultivation. Under 37/28 °C cultivation conditions, flavivirus VLPs production significantly increased in various mammalian cell lines regardless of whether its expression was transiently transfected or clonally selected cells. Remarkably, clonally selected cell lines expressing flavivirus VLPs consistently achieved yields exceeding 1 μg/ml. Binding affinity analyses using monoclonal antibodies revealed similar binding patterns for VLPs of genotype I (GI) JEV, GIII JEV, West Nile virus (WNV), and dengue virus serotype 2 (DENV-2) produced under both 37 °C or 37/28 °C cultivation conditions. In summary, our study demonstrated that the production of flavivirus VLPs can be significantly improved under 37/28 °C cultivation conditions without affecting the conformational structure of the E protein. KEYPOINTS: • Low-temperature culture (37/28 °C) enhances production of flavivirus VLPs. • Flavivirus VLPs consistently achieved yields exceeding 1 μg/ml. • 37/28 °C cultivation did not alter the structure of flavivirus VLPs.
Topics: Chlorocebus aethiops; Animals; Flavivirus; Temperature; Encephalitis Virus, Japanese; Cold Temperature; COS Cells; Encephalitis, Japanese; Mammals
PubMed: 38416210
DOI: 10.1007/s00253-024-13064-y -
Veterinary World Jan 2024Despite the endemicity of Japanese encephalitis virus (JEV) in humans and animals in the Province of Bali, Indonesia, there is little data on whether seroconversion to...
BACKGROUND AND AIMS
Despite the endemicity of Japanese encephalitis virus (JEV) in humans and animals in the Province of Bali, Indonesia, there is little data on whether seroconversion to the virus occurs in pigs, JEV genotypes circulating, and it's potential mosquito vectors in the area. The aims of this study were to (i) Determine whether JEV infection in Balinese pigs occurs before reaching their sexual maturity, (ii) identify the genotypes of circulating JEV, and (iii) identify potential JEV mosquito vectors at the study sites in urban and peri-urban areas of Bali.
MATERIALS AND METHODS
Sixteen 1-week-old Landrace piglets from two different sows were housed in Denpasar. Similarly, 18 one-week-old mixed-breed piglets of two different sows were housed in Badung Regency. The piglets were bled every 1 to 4 weeks for up to 24 weeks. Serum samples from the 11 piglets were tested for antibodies against JEV, and seroconversion-suspected sera were titrated using an enzyme-linked immunosorbent assay. Blood of seroconverted sera from pigs were tested using polymerase chain reaction (PCR) to detect the genetic sequence of JEV. The mosquitoes in the sentinels were trapped throughout the study period to identify the potential mosquito vectors of JEV.
RESULTS
Antibodies were detected in most of the selected piglets' sera from weeks 1 to 24 of their age. However, sera of pig B9 collected from the sentinel setting in Badung Regency showed a four-fold increase in antibody titer from week 4 to week 8, indicating seroconversion. PCR testing of blood from B9 (pooled blood sample collected from week 5 to week 8) identified JEV nucleic acids, which were phylogenetically classified as belonging to the JEV genotype III. Meanwhile, 1271 of two genera of mosquitoes, spp. and spp. were trapped in the pig sentinels.
CONCLUSION
JEV seroconversion likely occurs before the pig reaches sexual maturity in Badung Regency. Sequence data indicate that JEV genotype III is circulating in the pig sentinel setting in the regency; however, circulating genotypes need to be clarified through increased surveillance. Meanwhile, spp. and most likely and spp. were the dominant mosquitoes present in the study sites set in the urban area of Denpasar and peri-urban areas of Badung, Bali, indicating that these are likely vectors in spread of JEV in the region.
PubMed: 38406355
DOI: 10.14202/vetworld.2024.89-98 -
MedRxiv : the Preprint Server For... Feb 2024Acute Encephalitis Syndrome (AES) causes significant morbidity and mortality worldwide. In Nepal, Japanese encephalitis virus (JEV) accounts for ~ 5-20% of AES cases,...
Acute Encephalitis Syndrome (AES) causes significant morbidity and mortality worldwide. In Nepal, Japanese encephalitis virus (JEV) accounts for ~ 5-20% of AES cases, but ~75% of AES cases are of unknown etiology. We identified a gemykibivirus in CSF collected in 2020 from a male child with AES using metagenomic next-generation sequencing. Gemykibiviruses are single stranded, circular DNA viruses in the family . The complete genome of 2211 nucleotides was sequenced which shared 98.69% nucleotide identity to its closest relative, Human associated gemykibivirus 2 isolate SAfia-449D. Two real-time PCR assays were designed, and screening of 337 CSF and 164 serum samples from AES patients in Nepal collected in 2020 and 2022 yielded 11 CSF and 1 serum sample that were positive in both PCR assays. Complete genomes of 7 of the positives were sequenced. These results identify a candidate etiologic agent of encephalitis in Nepal.
PubMed: 38405898
DOI: 10.1101/2024.02.13.24302648 -
Viruses Feb 2024Tick-borne encephalitis is a vaccine-preventable disease of concern for public health in large parts of Europe, with EU notification rates increasing since 2018. It is...
Multiplex Serology for Sensitive and Specific Flavivirus IgG Detection: Addition of Envelope Protein Domain III to NS1 Increases Sensitivity for Tick-Borne Encephalitis Virus IgG Detection.
Tick-borne encephalitis is a vaccine-preventable disease of concern for public health in large parts of Europe, with EU notification rates increasing since 2018. It is caused by the orthoflavivirus tick-borne encephalitis virus (TBEV) and a diagnosis of infection is mainly based on serology due to its short viremic phase, often before symptom onset. The interpretation of TBEV serology is hampered by a history of orthoflavivirus vaccination and by previous infections with related orthoflaviviruses. Here, we sought to improve TBEV sero-diagnostics using an antigen combination of in-house expressed NS1 and EDIII in a multiplex, low-specimen-volume set-up for the detection of immune responses to TBEV and other clinically important orthoflaviviruses (i.e., West Nile virus, dengue virus, Japanese encephalitis virus, Usutu virus and Zika virus). We show that the combined use of NS1 and EDIII results in both a specific and sensitive test for the detection of TBEV IgG for patient diagnostics, vaccination responses and in seroprevalence studies. This novel approach potentially allows for a low volume-based, simultaneous analysis of IgG responses to a range of orthoflaviviruses with overlapping geographic circulations and clinical manifestations.
Topics: Humans; Encephalitis Viruses, Tick-Borne; Protein Domains; Seroepidemiologic Studies; Antibodies, Viral; Flavivirus Infections; Encephalitis, Tick-Borne; Encephalitis, Viral; Immunoglobulin G; Zika Virus; Zika Virus Infection
PubMed: 38400061
DOI: 10.3390/v16020286 -
Viruses Feb 2024Japanese encephalitis virus (JEV) causes acute encephalitis in humans and is of major public health concern in most Asian regions. Dogs are suitable sentinels for...
Japanese encephalitis virus (JEV) causes acute encephalitis in humans and is of major public health concern in most Asian regions. Dogs are suitable sentinels for assessing the risk of JEV infection in humans. A neutralization test (NT) or an enzyme-linked immunosorbent assay (ELISA) is used for the serological detection of JEV in dogs; however, these tests have several limitations, and, thus, a more convenient and reliable alternative test is needed. In this study, a colloidal gold immunochromatographic strip (ICS), using a purified recombinant EDIII protein, was established for the serological survey of JEV infection in dogs. The results show that the ICSs could specifically detect JEV antibodies within 10 min without cross-reactions with antibodies against other canine viruses. The test strips could detect anti-JEV in serum with dilution up to 640 times, showing high sensitivity. The coincidence rate with the NT test was higher than 96.6%. Among 586 serum samples from dogs in Shanghai examined using the ICS test, 179 (29.98%) were found to be positive for JEV antibodies, and the high seropositivity of JEV in dogs in China was significantly correlated with the season and living environment. In summary, we developed an accurate and economical ICS for the rapid detection of anti-JEV in dog serum samples with great potential for the surveillance of JEV in dogs.
Topics: Dogs; Animals; Humans; Encephalitis Virus, Japanese; Gold Colloid; China; Encephalitis, Japanese; Enzyme-Linked Immunosorbent Assay; Antibodies, Viral; Recombinant Proteins
PubMed: 38400034
DOI: 10.3390/v16020258 -
Viruses Jan 2024Japanese encephalitis virus (JEV) belongs to the family and is a representative mosquito-borne flavivirus responsible for acute encephalitis and meningitis in humans.... (Review)
Review
Japanese encephalitis virus (JEV) belongs to the family and is a representative mosquito-borne flavivirus responsible for acute encephalitis and meningitis in humans. Despite the availability of vaccines, JEV remains a major public health threat with the potential to spread globally. According to the World Health Organization (WHO), there are an estimated 69,000 cases of JE each year, and this figure is probably an underestimate. The majority of JE victims are children in endemic areas, and almost half of the surviving patients have motor or cognitive sequelae. Thus, the absence of a clinically approved drug for the treatment of JE defines an urgent medical need. Recently, several promising and potential drug candidates were reported through drug repurposing studies, high-throughput drug library screening, and de novo design. This review focuses on the historical aspects of JEV, the biology of JEV replication, targets for therapeutic strategies, a target product profile, and drug development initiatives.
Topics: Child; Animals; Humans; Encephalitis Virus, Japanese; Encephalitis, Japanese; Encephalitis, Viral; High-Throughput Screening Assays; Drug Development
PubMed: 38399978
DOI: 10.3390/v16020202 -
Microorganisms Feb 2024Human antigen R (HuR) is an RNA-binding protein that regulates the post-transcriptional reaction of its target mRNAs. HuR is a critical factor in cancer development and...
Human antigen R (HuR) is an RNA-binding protein that regulates the post-transcriptional reaction of its target mRNAs. HuR is a critical factor in cancer development and has been identified as a potential target in many cancer models. It participates in the viral life cycle by binding to viral RNAs. In prior work, we used CRISPR/Cas9 screening to identify HuR as a prospective host factor facilitating Japanese encephalitis virus (JEV) infection. The gene was successfully knocked out in U251 cell lines using the CRISPR/Cas9 gene-editing system, with no significant difference in cell growth between U251-WT and U251-HuR-KO2 cells. Here, we experimentally demonstrate for the first time that the knockout of the gene inhibits the replication ability of JEV in U251 cell lines. These results play an essential role in regulating the replication level of JEV and providing new insights into virus-host interactions and potential antiviral strategies. It also offers a platform for investigating the function of HuR in the life cycle of flaviviruses.
PubMed: 38399718
DOI: 10.3390/microorganisms12020314 -
Indian Journal of Pathology &... Nov 2023The incidence of meningoencephalitis (ME) in India is poorly understood, and the exact etiological diagnosis is often not possible. This study was planned to elucidate...
BACKGROUND
The incidence of meningoencephalitis (ME) in India is poorly understood, and the exact etiological diagnosis is often not possible. This study was planned to elucidate the bacterial and viral etiological diagnosis of ME in children less than 5 years of age.
MATERIAL AND METHODS
The present study was conducted in Virus Research and Diagnostic Laboratory (VRDL), Department of Microbiology, King George's Medical University, Lucknow, from July 2020 to June 2022. Serum, cerebrospinal fluid (CSF), and nose/throat swabs were collected from all the enrolled cases of meningoencephalitis in children below 5 years of age and tested for various etiological agents by ELISA and/or real-time PCR.
RESULTS
Of 130 enrolled cases, 50 (38.5%) cases tested positive for one or more etiological agents. Etiological agents of ME detected were Japanese encephalitis virus (JEV) (8.46%), adenovirus (6.92%), influenza virus (5.38%), dengue virus (3.85%), Parvo B-19 virus (3.08%), Orientia tsutsugamushi (3.08%), Herpes Simplex Virus-1 (HSV-1) (1.54%), measles virus (1.54%), and Varicella-Zoster Virus (VZV) (1.54%). Rubella virus, Chikungunya virus (CHKV), Mumps virus, Enteroviruses, Parecho virus, John Cunningham virus (JC), BK virus, Nipah virus, Kyasanur Forest Disease virus (KFD), Chandipura virus, Herpes Simplex Virus (HSV-2), SARS CoV-2, N. Meningitides, and H. Influenzae were tested but not detected in any of the cases.
CONCLUSION
We identified the etiological agents in 50/130 (38.5%) suspected ME cases in children less than 5 years of age, using molecular and ELISA-based diagnostic methods. The four most common pathogens detected were JEV, adenovirus, influenza virus, and dengue virus.
PubMed: 38394398
DOI: 10.4103/ijpm.ijpm_60_23 -
Marine Drugs Feb 2024The Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus that primarily affects people in Asia and seriously threatens public health. Considering the rising...
The Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus that primarily affects people in Asia and seriously threatens public health. Considering the rising occurrence rates and lack of targeted antiviral treatments, it is essential to comprehend and tackle obstacles related to JEV in order to lessen its influence on world health. This investigation explores compounds derived from marine brown algae (Phaeophyceae) as potential inhibitors of JEV RNA-dependent RNA polymerase (RdRp), a critical enzyme in the virus's replication cycle. Employing the computational virtual screen approach, four compounds, i.e., CMNPD16749, CMNPD2606, CMNPD27817, and CMNPD23662, with favorable binding energies ranging from -15.7 Kcal/mol to -13.9 kcal/mol were identified. Subsequently, through molecular docking analysis, the interactions responsible for the binding stability between the target protein and hit molecules compared to the reference molecule Galidesvir were studied. Further, through extensive molecular dynamic (MD) simulation studies at 200 ns, it was confirmed that each docked complex showed acceptable dynamic stability compared to the reference molecule. These findings were further validated using MM/PBSA free binding energy calculations, PCA analysis and free energy landscape construction. These computational findings suggested that the brown algae-derived compounds may act as an antiviral drug against JEV infection and lay a crucial foundation for future experimental studies against JEV.
Topics: Animals; Humans; Encephalitis Virus, Japanese; RNA-Dependent RNA Polymerase; Molecular Docking Simulation; Virus Replication; Encephalitis, Japanese
PubMed: 38393063
DOI: 10.3390/md22020092