scholarly journals Antibodies against West Nile Virus Nonstructural Protein NS1 Prevent Lethal Infection through Fc γ Receptor-Dependent and -Independent Mechanisms

2006 ◽  
Vol 80 (3) ◽  
pp. 1340-1351 ◽  
Author(s):  
Kyung Min Chung ◽  
Grant E. Nybakken ◽  
Bruce S. Thompson ◽  
Michael J. Engle ◽  
Anantha Marri ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Early Stage ◽  
Nonstructural Protein ◽  
Distinct Region ◽  
Binding Assays ◽  
West Nile ◽  
Tick Borne Encephalitis ◽  
Lethal Infection ◽  
Infected Insect ◽  
Dependent Pathway

ABSTRACT The flavivirus nonstructural protein NS1 is a highly conserved secreted glycoprotein that does not package with the virion. Immunization with NS1 elicits a protective immune response against yellow fever, dengue, and tick-borne encephalitis flaviviruses through poorly defined mechanisms. In this study, we purified a recombinant, secreted form of West Nile virus (WNV) NS1 glycoprotein from baculovirus-infected insect cells and generated 22 new NS1-specific monoclonal antibodies (MAbs). By performing competitive binding assays and expressing truncated NS1 proteins on the surface of yeast (Saccharomyces cerevisiae) and in bacteria, we mapped 21 of the newly generated MAbs to three NS1 fragments. Prophylaxis of C57BL/6 mice with any of four MAbs (10NS1, 14NS1, 16NS1, and 17NS1) strongly protected against lethal WNV infection (75 to 95% survival, respectively) compared to saline-treated controls (17% survival). In contrast, other anti-NS1 MAbs of the same isotype provided no significant protection. Notably, 14NS1 and 16NS1 also demonstrated marked efficacy as postexposure therapy, even when administered as a single dose 4 days after infection. Virologic analysis showed that 17NS1 protects at an early stage in infection through a C1q-independent and Fc γ receptor-dependent pathway. Interestingly, 14NS1, which maps to a distinct region on NS1, protected through a C1q- and Fc γ receptor-independent mechanism. Overall, our data suggest that distinct regions of NS1 can elicit protective humoral immunity against WNV through different mechanisms.

scholarly journals Potential Dual Role of West Nile Virus NS2B in Orchestrating NS3 Enzymatic Activity in Viral Replication

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 216
Author(s):  
Alanna C. Tseng ◽  
Vivek R. Nerurkar ◽  
Kabi R. Neupane ◽  
Helmut Kae ◽  
Pakieli H. Kaufusi
Keyword(s):  
West Nile Virus ◽  
Enzymatic Activity ◽  
Nonstructural Protein ◽  
Antiviral Drug ◽  
West Nile ◽  
Biochemical Assays ◽  
In Trans ◽  
Viral Polyprotein ◽  
Ns3 Protease

West Nile virus (WNV) nonstructural protein 3 (NS3) harbors the viral triphosphatase and helicase for viral RNA synthesis and, together with NS2B, constitutes the protease responsible for polyprotein processing. NS3 is a soluble protein, but it is localized to specialized compartments at the rough endoplasmic reticulum (RER), where its enzymatic functions are essential for virus replication. However, the mechanistic details behind the recruitment of NS3 from the cytoplasm to the RER have not yet been fully elucidated. In this study, we employed immunofluorescence and biochemical assays to demonstrate that NS3, when expressed individually and when cleaved from the viral polyprotein, is localized exclusively to the cytoplasm. Furthermore, NS3 appeared to be peripherally recruited to the RER and proteolytically active when NS2B was provided in trans. Thus, we provide evidence for a potential additional role for NS2B in not only serving as the cofactor for the NS3 protease, but also in recruiting NS3 from the cytoplasm to the RER for proper enzymatic activity. Results from our study suggest that targeting the interaction between NS2B and NS3 in disrupting the NS3 ER localization may be an attractive avenue for antiviral drug discovery.

Surveillance on antibodies against West Nile virus, Usutu virus, tick-borne encephalitis virus and Tribeč virus in wild birds in Drienovská wetland, Slovakia

Biologia ◽  
2019 ◽  
Vol 74 (7) ◽  
pp. 813-820 ◽  
Author(s):  
Tomáš Csank ◽  
Ľuboš Korytár ◽  
Terézia Pošiváková ◽  
Tamás Bakonyi ◽  
Juraj Pistl ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Wild Birds ◽  
Encephalitis Virus ◽  
West Nile ◽  
Usutu Virus ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus

scholarly journals Nonstructural Protein 1-Specific Immunoglobulin M and G Antibody Capture Enzyme-Linked Immunosorbent Assays in Diagnosis of Flaviviral Infections in Humans

2014 ◽  
Vol 53 (2) ◽  
pp. 557-566 ◽  
Author(s):  
Day-Yu Chao ◽  
Jedhan Ucat Galula ◽  
Wen-Fan Shen ◽  
Brent S. Davis ◽  
Gwong-Jen J. Chang
Keyword(s):  
West Nile Virus ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Nonstructural Protein ◽  
Encephalitis Virus ◽  
Igg Antibody ◽  
West Nile ◽  
Dengue Viruses ◽  
Nonstructural Protein 1 ◽  
Antibody Capture

IgM antibody- and IgG antibody-capture enzyme-linked immunosorbent assays (MAC/GAC-ELISAs) targeted at envelope protein (E) of dengue viruses (DENV), West Nile virus, and Japanese encephalitis virus (JEV) are widely used as serodiagnostic tests for presumptive confirmation of viral infection. Antibodies directed against the flavivirus nonstructural protein 1 (NS1) have been proposed as serological markers of natural infections among vaccinated populations. The aim of the current study is to optimize an IgM and IgG antibody-capture ELISA (MAC/GAC-ELISA) to detect anti-NS1 antibodies and compare it with anti-E MAC/GAC-ELISA. Plasmids to express premembrane/envelope (prM/E) or NS1 proteins of six medically important flaviviruses, including dengue viruses (DENV-1 to DENV-4), West Nile virus (WNV), and Japanese encephalitis virus (JEV), were constructed. These plasmids were used for the production of prM/E-containing virus-like particles (VLPs) and secreted NS1 (sNS1) from COS-1 cells. Archived clinical specimens from patients with confirmed DENV, JEV, and WNV infections, along with naive sera, were subjected to NS1-MAC/GAC-ELISAs before or after depletion of anti-prM/E antibodies by preabsorption with or without VLPs. Human serum specimens from previously confirmed DENV infections showed significantly enhanced positive-to-negative (P/N) ratios for NS1-MAC/GAC-ELISAs after the depletion of anti-prM/E antibodies. No statistical differences in sensitivities and specificities were found between the newly developed NS1- and VLP-MAC/GAC-ELISAs. Further application of the assays to WNV- and JEV-infected serum panels showed similar results. A novel approach to perform MAC/GAC-ELISAs for NS1 antibody detection was successfully developed with great potential to differentiate antibodies elicited by the tetravalent chimeric yellow fever-17D/dengue vaccine or DENV infection.

scholarly journals An interaction between the methyltransferase and RNA dependent RNA polymerase domains of the West Nile virus NS5 protein

2013 ◽  
Vol 94 (9) ◽  
pp. 1961-1971 ◽  
Author(s):  
Cindy S. E. Tan ◽  
Jody M. Hobson-Peters ◽  
Martin J. Stoermer ◽  
David P. Fairlie ◽  
Alexander A. Khromykh ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Rna Polymerase ◽  
Genetic Interaction ◽  
Nonstructural Protein ◽  
Specific Interaction ◽  
Simian Virus 40 ◽  
T Antigen ◽  
Rna Dependent Rna Polymerase ◽  
West Nile

The flavivirus nonstructural protein 5 (NS5) is a large protein that is structurally conserved among members of the genus, making it an attractive target for antiviral drug development. The protein contains a methyltransferase (MTase) domain and an RNA dependent RNA polymerase (POL) domain. Previous studies with dengue viruses have identified a genetic interaction between residues 46–49 in the αA3-motif in the MTase and residue 512 in POL. These genetic interactions are consistent with structural modelling of these domains in West Nile virus (WNV) NS5 that predict close proximity of these regions of the two domains, and potentially a functional interaction mediated via the αA3-motif. To demonstrate an interaction between the MTase and POL domains of the WNV NS5 protein, we co-expressed affinity-tagged recombinant MTase and POL proteins in human embryonic kidney cells with simian virus 40 large T antigen (HEK293T cells) and performed pulldown assays using an antibody to the flag tag on POL. Western blot analysis with an anti-MTase mAb revealed that the MTase protein was specifically co-immunoprecipitated with POL, providing the first evidence of a specific interaction between these domains. To further assess the role of the αA3 helix in this interaction, selected residues in this motif were mutated in the recombinant MTase and the effect on POL interaction determined by the pulldown assay. These mutations were also introduced into a WNV infectious clone (FLSDX) and the replication properties of these mutant viruses assessed. While none of the αA3 mutations had a significant effect on the MTase–POL association in pulldown assays, suggesting that these residues were not specific to the interaction, an E46L mutation completely abolished virus viability indicating a critical requirement of this residue in replication. Failure to generate compensatory mutations in POL to rescue replication, even after several passages of the transfection supernatant in Vero cells, precluded further conclusion of the role of this residue in the context of MTase–POL interactions.

A nationwide seroprevalence screening for West Nile virus and Tick-borne encephalitis virus in the population of Bulgaria

2017 ◽  
Vol 89 (10) ◽  
pp. 1875-1878 ◽  
Author(s):  
Iva Christova ◽  
Elitsa Panayotova ◽  
Simona Tchakarova ◽  
Evgenia Taseva ◽  
Iva Trifonova ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Encephalitis Virus ◽  
West Nile ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus

scholarly journals Immunization with West Nile virus envelope domain III protects mice against lethal infection with homologous and heterologous virus

Vaccine ◽  
2008 ◽  
Vol 26 (2) ◽  
pp. 153-157 ◽  
Author(s):  
Byron E. Martina ◽  
Penelopie Koraka ◽  
Petra van den Doel ◽  
Geert van Amerongen ◽  
Guus F. Rimmelzwaan ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Virus Envelope ◽  
West Nile ◽  
Lethal Infection ◽  
Heterologous Virus ◽  
Domain Iii

scholarly journals A VLP-based vaccine targeting domain III of the West Nile virus E protein protects from lethal infection in mice

2010 ◽  
Vol 7 (1) ◽  
Author(s):  
Gunther Spohn ◽  
Gary T Jennings ◽  
Byron EE Martina ◽  
Iris Keller ◽  
Markus Beck ◽  
...  
Keyword(s):  
West Nile Virus ◽  
The West ◽  
West Nile ◽  
E Protein ◽  
Lethal Infection ◽  
Domain Iii

Serological Evidence of Tick-Borne Encephalitis and West Nile Virus Infections Among Children with Arthritis in Turkey

2019 ◽  
Vol 19 (6) ◽  
pp. 446-449 ◽  
Author(s):  
Huseyin Yilmaz ◽  
Kenan Barut ◽  
Asiye Karakullukcu ◽  
Ozgur Kasapcopur ◽  
Bekir Kocazeybek ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Virus Infections ◽  
Serological Evidence ◽  
West Nile ◽  
Tick Borne Encephalitis

scholarly journals Differential Effects of Mutations in NS4B on West Nile Virus Replication and Inhibition of Interferon Signaling

2007 ◽  
Vol 81 (21) ◽  
pp. 11809-11816 ◽  
Author(s):  
Jared D. Evans ◽  
Christoph Seeger
Keyword(s):  
West Nile Virus ◽  
Nonstructural Protein ◽  
Signal Transduction Pathway ◽  
Janus Kinase ◽  
Transduction Pathway ◽  
Interferon Signaling ◽  
Structural Genes ◽  
West Nile ◽  
Tyrosine Kinase 2 ◽  
Janus Kinase 1

ABSTRACT West Nile virus (WNV) is a human pathogen that can cause symptomatic infections associated with meningitis and encephalitis. Previously, we demonstrated that replication of WNV inhibits the interferon (IFN) signal transduction pathway by preventing the accumulation of phosphorylated Janus kinase 1 (JAK1) and tyrosine kinase 2 (Tyk2) (J. T. Guo et al., J. Virol. 79:1343-1350, 2005). Through a genetic analysis, we have now identified a determinant on the nonstructural protein 4B (NS4B) that controls IFN resistance in HeLa cells expressing subgenomic WNV replicons lacking the structural genes. However, in the context of infectious genomes, the same determinant did not influence IFN signaling. Thus, our results indicate that NS4B may be sufficient to inhibit the IFN response in replicon cells and suggest a role for structural genes, or as yet unknown interactions, in the inhibition of the IFN signaling pathway during WNV infections.

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