-
Science (New York, N.Y.) Jan 2021Medically important flaviviruses cause diverse disease pathologies and collectively are responsible for a major global disease burden. A contributing factor to...
Medically important flaviviruses cause diverse disease pathologies and collectively are responsible for a major global disease burden. A contributing factor to pathogenesis is secreted flavivirus nonstructural protein 1 (NS1). Despite demonstrated protection by NS1-specific antibodies against lethal flavivirus challenge, the structural and mechanistic basis remains unknown. Here, we present three crystal structures of full-length dengue virus NS1 complexed with a flavivirus-cross-reactive, NS1-specific monoclonal antibody, 2B7, at resolutions between 2.89 and 3.96 angstroms. These structures reveal a protective mechanism by which two domains of NS1 are antagonized simultaneously. The NS1 wing domain mediates cell binding, whereas the β-ladder triggers downstream events, both of which are required for dengue, Zika, and West Nile virus NS1-mediated endothelial dysfunction. These observations provide a mechanistic explanation for 2B7 protection against NS1-induced pathology and demonstrate the potential of one antibody to treat infections by multiple flaviviruses.
Topics: Animals; Antibodies, Monoclonal; Antibodies, Neutralizing; Antibodies, Viral; Cross Reactions; Crystallography, X-Ray; Dengue; Dengue Virus; Endothelium; Glycocalyx; Humans; Mice; Protein Conformation, beta-Strand; Protein Domains; Viral Nonstructural Proteins; West Nile Fever; West Nile virus; Zika Virus; Zika Virus Infection
PubMed: 33414220
DOI: 10.1126/science.abc0476 -
Journal of Virology Nov 2021Cellular factors have important roles in all facets of the flavivirus replication cycle. Deciphering viral-host protein interactions is essential for understanding the...
Cellular factors have important roles in all facets of the flavivirus replication cycle. Deciphering viral-host protein interactions is essential for understanding the flavivirus life cycle as well as development of effective antiviral strategies. To uncover novel host factors that are co-opted by multiple flaviviruses, a CRISPR/Cas9 genome wide knockout (KO) screen was employed to identify genes required for replication of Zika virus (ZIKV). Receptor for Activated Protein C Kinase 1 (RACK1) was identified as a novel host factor required for ZIKV replication, which was confirmed via complementary experiments. Depletion of RACK1 via siRNA demonstrated that RACK1 is important for replication of a wide range of mosquito- and tick-borne flaviviruses, including West Nile Virus (WNV), Dengue Virus (DENV), Powassan Virus (POWV) and Langat Virus (LGTV) as well as the coronavirus SARS-CoV-2, but not for YFV, EBOV, VSV or HSV. Notably, flavivirus replication was only abrogated when RACK1 expression was dampened prior to infection. Utilising a non-replicative flavivirus model, we show altered morphology of viral replication factories and reduced formation of vesicle packets (VPs) in cells lacking RACK1 expression. In addition, RACK1 interacted with NS1 protein from multiple flaviviruses; a key protein for replication complex formation. Overall, these findings reveal RACK1's crucial role to the biogenesis of pan-flavivirus replication organelles. Cellular factors are critical in all facets of viral lifecycles, where overlapping interactions between the virus and host can be exploited as possible avenues for the development of antiviral therapeutics. Using a genome-wide CRISPR knockout screening approach to identify novel cellular factors important for flavivirus replication we identified RACK1 as a pro-viral host factor for both mosquito- and tick-borne flaviviruses in addition to SARS-CoV-2. Using an innovative flavivirus protein expression system, we demonstrate for the first time the impact of the loss of RACK1 on the formation of viral replication factories known as 'vesicle packets' (VPs). In addition, we show that RACK1 can interact with numerous flavivirus NS1 proteins as a potential mechanism by which VP formation can be induced by the former.
Topics: A549 Cells; Aedes; Animals; COVID-19; CRISPR-Cas Systems; Chlorocebus aethiops; Culicidae; Dengue Virus; Flavivirus; Genome-Wide Association Study; HEK293 Cells; Host-Pathogen Interactions; Humans; Neoplasm Proteins; RNA, Small Interfering; RNA, Viral; Receptors for Activated C Kinase; SARS-CoV-2; Vero Cells; Virus Replication; West Nile virus; Zika Virus; Zika Virus Infection
PubMed: 34586867
DOI: 10.1128/JVI.00596-21 -
The Journal of Experimental Medicine Sep 2023Mosquito-borne West Nile virus (WNV) infection is benign in most individuals but can cause encephalitis in <1% of infected individuals. We show that ∼35% of patients...
Mosquito-borne West Nile virus (WNV) infection is benign in most individuals but can cause encephalitis in <1% of infected individuals. We show that ∼35% of patients hospitalized for WNV disease (WNVD) in six independent cohorts from the EU and USA carry auto-Abs neutralizing IFN-α and/or -ω. The prevalence of these antibodies is highest in patients with encephalitis (∼40%), and that in individuals with silent WNV infection is as low as that in the general population. The odds ratios for WNVD in individuals with these auto-Abs relative to those without them in the general population range from 19.0 (95% CI 15.0-24.0, P value <10-15) for auto-Abs neutralizing only 100 pg/ml IFN-α and/or IFN-ω to 127.4 (CI 87.1-186.4, P value <10-15) for auto-Abs neutralizing both IFN-α and IFN-ω at a concentration of 10 ng/ml. These antibodies block the protective effect of IFN-α in Vero cells infected with WNV in vitro. Auto-Abs neutralizing IFN-α and/or IFN-ω underlie ∼40% of cases of WNV encephalitis.
Topics: Animals; Chlorocebus aethiops; Humans; West Nile Fever; West Nile virus; Vero Cells; Autoantibodies; Antibodies, Viral; Interferon Type I; Interferon-alpha
PubMed: 37347462
DOI: 10.1084/jem.20230661 -
Viruses Sep 2022The beginning decades of the 21st century have been marked by multiple emergence and re-emergence phenomena of viral diseases [...].
The beginning decades of the 21st century have been marked by multiple emergence and re-emergence phenomena of viral diseases [...].
Topics: Humans; Encephalitis Viruses, Tick-Borne; West Nile Fever; West Nile virus; Encephalitis, Tick-Borne; Antibodies, Viral
PubMed: 36298675
DOI: 10.3390/v14102120 -
Methods in Molecular Biology (Clifton,... 2023West Nile virus (WNV) is a mosquito-borne, single-stranded, positive-sense RNA virus belonging to the Flaviviridae family. After WNV gains entry through an infected...
West Nile virus (WNV) is a mosquito-borne, single-stranded, positive-sense RNA virus belonging to the Flaviviridae family. After WNV gains entry through an infected mosquito bite, it replicates in a variety of human cell types and produces a viremia. Although the majority of infected individuals remain asymptomatic, the manifested symptoms in some people range from a mild fever to severe neurological disorder with high morbidity and mortality. In addition, many who recover from WNV neuroinvasive infection present with long-term deficits, including weakness, fatigue, and cognitive problems. Since entering the USA in 1999, WNV has become the most common mosquito-borne virus in North America. Despite the intensive research over 20 years, there are still no approved vaccines or specific treatments for humans, and it remains an urgent need to understand the pathogenesis of WNV and develop specific therapeutics and vaccines.
Topics: Animals; Humans; West Nile virus; West Nile Fever; Viremia; North America
PubMed: 36331759
DOI: 10.1007/978-1-0716-2760-0_1 -
Viruses Jul 2020West Nile virus (WNV) is a flavivirus transmitted by mosquitoes. Birds are the reservoir for the virus; humans, horses and other mammals are dead-end hosts. Infections...
West Nile virus (WNV) is a flavivirus transmitted by mosquitoes. Birds are the reservoir for the virus; humans, horses and other mammals are dead-end hosts. Infections caused by WNV in humans can vary from asymptomatic infections to West Nile fever (WNF) or West Nile neuroinvasive disease (WNND). In 1995, a serosurvey was performed in Slovenia on forest workers, and WNV specific IgG antibodies were confirmed in 6.8% of the screened samples, indicating that WNV is circulating in Slovenia. No human disease cases were detected in Slovenia until 2013, when the first case of WNV infection was confirmed in a retrospective study in a 79-year old man with meningitis. In 2018, three patients with WNND were confirmed by laboratory tests, with detection of IgM antibodies in the cerebrospinal fluid of the patients. In one of the patients, WNV RNA was detected in the urine sample. In 2017, 2018 and 2019, a mosquito study was performed in Slovenia. Mosquitoes were sampled on 14 control locations and 35 additional locations in 2019. No WNV was detected in mosquitoes in 2017 and 2019, but we confirmed the virus in a pool of sp. mosquitoes in 2018. The virus was successfully isolated, and complete genome sequence was acquired. The whole genome of the WNV was also sequenced from the patient's urine sample. The whole genome sequences of the WNV virus detected in Slovenian patient and mosquito indicate the virus most likely spread from the north, because of the geographic proximity and because the sequences cluster with the Austrian and Hungarian sequences. A sentinel study was performed on dog sera samples, and we were able to confirm IgG antibodies in 1.8% and 4.3% of the samples in 2017 and 2018, respectively. Though Slovenia is not a highly endemic country for WNV, we have established that the virus circulates in Slovenia.
Topics: Aged; Animals; Antibodies, Viral; Culex; Culicidae; Dog Diseases; Dogs; Female; Genome, Viral; Humans; Male; Middle Aged; Phylogeny; Retrospective Studies; Slovenia; West Nile Fever; West Nile virus
PubMed: 32635155
DOI: 10.3390/v12070720 -
PLoS Neglected Tropical Diseases Oct 2022The detection of the first cases of transfusion-transmitted West Nile virus in 2002 posed a new challenge for transfusion safety. Institutions like the World Health...
BACKGROUND
The detection of the first cases of transfusion-transmitted West Nile virus in 2002 posed a new challenge for transfusion safety. Institutions like the World Health Organization have stated that blood transfusion centers need to know the epidemiology of the different emerging infectious agents and their impact on blood transfusion. The aim of the study is to review the published cases of arbovirus transmission through transfusion of blood or blood components and to analyze their main clinical and epidemiological characteristics.
MATERIAL AND METHODS
Systematic literature searches were conducted in MEDLINE, Embase and Scopus. Pairs of review authors selected a variety of scientific publications reporting cases of transfusion-transmitted arboviruses. Main clinical and epidemiological characteristics were reviewed of the cases described. The study protocol was registered in PROSPERO CRD42021270355.
RESULTS
A total of 74 cases of transfusion-transmitted infections were identified from 10 arboviruses: West Nile virus (n = 42), dengue virus (n = 18), Zika virus (n = 3), yellow fever vaccine virus (n = 3), tick-borne encephalitis virus (n = 2), Japanese encephalitis virus (n = 2), Powassan virus (n = 1), St. Louis encephalitis virus (n = 1), Ross River virus (n = 1) and Colorado tick fever virus (n = 1). The blood component most commonly involved was red blood cells (N = 35, 47.3%; 95% confidence interval [CI] 35.9% to 58.7%). In 54.1% (N = 40; 95% CI: 42.7%-65.47%) of the cases, the recipient was immunosuppressed. Transmission resulted in death in 18.9% (N = 14; 95% CI: 10.0%-27.8%) of the recipients. In addition, 18 additional arboviruses were identified with a potential threat to transfusion safety.
DISCUSSION
In the last 20 years, the number of published cases of transfusion-transmitted arboviruses increased notably, implicating new arboviruses. In addition, a significant number of arboviruses that may pose a threat to transfusion safety were detected. In the coming years, it is expected that transmission of arboviruses will continue to expand globally. It is therefore essential that all responsible agencies prepare for this potential threat to transfusion safety.
Topics: Humans; Arbovirus Infections; Arboviruses; Blood Transfusion; West Nile virus; Yellow Fever Vaccine; Zika Virus; Zika Virus Infection
PubMed: 36201547
DOI: 10.1371/journal.pntd.0010843 -
Frontiers in Cellular and Infection... 2022The genus is made up of viruses that are either mosquito-borne or tick-borne and other viruses transmitted by unknown vectors. Flaviviruses present a significant threat... (Review)
Review
The genus is made up of viruses that are either mosquito-borne or tick-borne and other viruses transmitted by unknown vectors. Flaviviruses present a significant threat to global health and infect up to 400 million of people annually. As the climate continues to change throughout the world, these viruses have become prominent infections, with increasing number of infections being detected beyond tropical borders. These include dengue virus (DENV), West Nile virus (WNV), Japanese encephalitis virus (JEV), and Zika virus (ZIKV). Several highly conserved epitopes of flaviviruses had been identified and reported to interact with antibodies, which lead to cross-reactivity results. The major interest of this review paper is mainly focused on the serological cross-reactivity between DENV serotypes, ZIKV, WNV, and JEV. Direct and molecular techniques are required in the diagnosis of -associated human disease. In this review, the serological assays such as neutralization tests, enzyme-linked immunosorbent assay, hemagglutination-inhibition test, Western blot test, and immunofluorescence test will be discussed. Serological assays that have been developed are able to detect different immunoglobulin isotypes (IgM, IgG, and IgA); however, it is challenging when interpreting the serological results due to the broad antigenic cross-reactivity of antibodies to these viruses. However, the neutralization tests are still considered as the gold standard to differentiate these flaviviruses.
Topics: Animals; Antibodies, Viral; Cross Reactions; Dengue Virus; Encephalitis Virus, Japanese; Enzyme-Linked Immunosorbent Assay; Epitopes; Flavivirus; Humans; Immunoglobulin A; Immunoglobulin G; Immunoglobulin M; Mosquito Vectors; West Nile virus; Zika Virus; Zika Virus Infection
PubMed: 36189346
DOI: 10.3389/fcimb.2022.975398 -
Ugeskrift For Laeger Mar 2023This is a case report of encephalitis and myeloradiculitis due to West Nile virus (WNV) with a fatal outcome in a 76-year-old male returning from a vacation in Serbia....
This is a case report of encephalitis and myeloradiculitis due to West Nile virus (WNV) with a fatal outcome in a 76-year-old male returning from a vacation in Serbia. In 2022 during transmission season, there was an outbreak of WNV infection in the southern part of Europe and the incidence is expected to increase globally in the future due to global warming. Currently, no antiviral treatments or vaccines against WNV are available for humans; hence, mosquito bite prevention is crucial in epidemic areas.
Topics: Male; Humans; Aged; West Nile Fever; West Nile virus; Europe; Disease Outbreaks; Epidemics
PubMed: 36999283
DOI: No ID Found