scholarly journals NS1 Protein Secretion during the Acute Phase of West Nile Virus Infection

2005 ◽  
Vol 79 (22) ◽  
pp. 13924-13933 ◽  
Author(s):  
Joanne Macdonald ◽  
Jessica Tonry ◽  
Roy A. Hall ◽  
Brent Williams ◽  
Gustavo Palacios ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Real Time ◽  
Real Time Pcr ◽  
Diagnostic Marker ◽  
Nonstructural Protein ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Ns1 Protein ◽  
West Nile ◽  
Time Period

ABSTRACT The West Nile virus (WNV) nonstructural protein NS1 is a protein of unknown function that is found within, associated with, and secreted from infected cells. We systematically investigated the kinetics of NS1 secretion in vitro and in vivo to determine the potential use of this protein as a diagnostic marker and to analyze NS1 secretion in relation to the infection cycle. A sensitive antigen capture enzyme-linked immunosorbent assay (ELISA) for detection of WNV NS1 (polyclonal-ACE) was developed, as well as a capture ELISA for the specific detection of NS1 multimers (4G4-ACE). The 4G4-ACE detected native NS1 antigens at high sensitivity, whereas the polyclonal-ACE had a higher specificity for recombinant forms of the protein. Applying these assays we found that only a small fraction of intracellular NS1 is secreted and that secretion of NS1 in tissue culture is delayed compared to the release of virus particles. In experimentally infected hamsters, NS1 was detected in the serum between days 3 and 8 postinfection, peaking on day 5, the day prior to the onset of clinical disease; immunoglobulin M (IgM) antibodies were detected at low levels on day 5 postinfection. Although real-time PCR gave the earliest indication of infection (day 1), the diagnostic performance of the 4G4-ACE was comparable to that of real-time PCR during the time period when NS1 was secreted. Moreover, the 4G4-ACE was found to be superior in performance to both the IgM and plaque assays during this time period, suggesting that NS1 is a viable early diagnostic marker of WNV infection.

Detection of West Nile virus lineages 1 and 2 by real-time PCR

2007 ◽  
Vol 146 (1-2) ◽  
pp. 355-358 ◽  
Author(s):  
Sonja Linke ◽  
Heinz Ellerbrok ◽  
Matthias Niedrig ◽  
Andreas Nitsche ◽  
Georg Pauli
Keyword(s):  
West Nile Virus ◽  
Real Time ◽  
Real Time Pcr ◽  
West Nile

West Nile Virus

2016 ◽  
Author(s):  
Matthew Finn
Keyword(s):  
West Nile Virus ◽  
Rna Virus ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mosquito Vector ◽  
West Nile ◽  
Csf Analysis ◽  
Neuroinvasive Disease ◽  
Breeding Grounds ◽  
Arboviral Disease

West Nile virus (WNV) is a single-stranded RNA virus of the Flavivirus family that is transmitted via a mosquito vector, typically causing fever and capable of causing meningoencephalitis. Although mortality is low, it can lead to debilitating neuroinvasive disease in some patients. WNV is a leading cause of domestically-acquired arboviral disease and most commonly occurs in late August and early September. Consider WNV in otherwise unexplained cases of meningitis or encephalitis. Initial testing should consist of cerebrospinal fluid (CSF) analysis and West Nile immunoglobulin M enzyme-linked immunosorbent assay in serum and/or CSF. WNV is a nationally notifiable disease. Prevention remains the key to controlling this disease. Reducing the breeding grounds of the Culex mosquito and using insect repellant to prevent bites are two important strategies.

Levels of circulating NS1 impact West Nile virus spread to the brain

2021 ◽  
Author(s):  
Alex W. Wessel ◽  
Kimberly A. Dowd ◽  
Scott B. Biering ◽  
Ping Zhang ◽  
Melissa A. Edeling ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Endothelial Dysfunction ◽  
Cell Surface ◽  
Virus Replication ◽  
Nonstructural Protein ◽  
Disease Outcome ◽  
Ns1 Protein ◽  
West Nile ◽  
Nonstructural Protein 1 ◽  
The Brain

Dengue (DENV) and West Nile (WNV) viruses are arthropod-transmitted flaviviruses that respectively cause systemic vascular leakage and encephalitis syndromes in humans. However, the viral factors contributing to these specific clinical disorders are not completely understood. Flavivirus nonstructural protein 1 (NS1) is required for replication, expressed on the cell surface, and secreted as a soluble glycoprotein, reaching high levels in the blood of infected individuals. Extracellular DENV and WNV NS1 interact with host proteins and cells, have immune evasion functions, and promote endothelial dysfunction in a tissue-specific manner. To characterize how differences in DENV and WNV NS1 might function in pathogenesis, we generated WNV NS1 variants with substitutions corresponding to residues found in DENV NS1. We discovered that the substitution NS1-P101K led to reduced WNV infectivity of the brain and attenuated lethality in infected mice, although the virus replicated efficiently in cell culture and peripheral organs and bound at wild-type levels to brain endothelial cells and complement components. The P101K substitution resulted in reduced NS1 antigenemia in mice, and this was associated with reduced WNV spread to the brain. As exogenous administration of NS1 protein rescued WNV brain infectivity in mice, we conclude that circulating WNV NS1 facilitates viral dissemination into the central nervous system and impacts disease outcome. IMPORTANCE Flavivirus NS1 serves as an essential scaffolding molecule during virus replication but also is expressed on the cell surface and secreted as a soluble glycoprotein that circulates in the blood of infected individuals. Although extracellular forms of NS1 are implicated in immune modulation and in promoting endothelial dysfunction at blood-tissue barriers, it has been challenging to study specific effects of NS1 on pathogenesis without disrupting its key role in virus replication. Here we assessed West Nile virus (WNV) NS1 variants that do not affect virus replication and evaluated their effects on pathogenesis in mice. Our characterization of WNV NS1-P101K suggests that the levels of NS1 in circulation facilitate WNV dissemination to the brain and disease outcome. Our findings help understand the role of NS1 during flavivirus infection and support antiviral strategies for targeting circulating forms of NS1.

Target Site Insensitivity Detection in Deltamethrin Resistant Culex pipiens Complex in Iran

2020 ◽  
Author(s):  
Reza ZEIDABADINEZHAD ◽  
Hassan VATANDOOST ◽  
Mohammad Reza ABAI ◽  
Navid DINPARAST DJADID ◽  
Abbasali RAZ ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Insecticide Resistance ◽  
Real Time ◽  
Real Time Pcr ◽  
Culex Pipiens ◽  
Mosquito Species ◽  
Knockdown Resistance ◽  
West Nile ◽  
Culex Pipiens Complex ◽  
Novel Approach

Background: Some mosquito species which belong to the Culex. pipiens complex are primary vectors for West Nile virus, Sindbis, Dirofilaria immitis, and many arboviruses. Knockdown resistance (kdr) mutations in the voltage-gated sodium channel (VGSC) gene of Cx. pipiens that is inherited, is one of the important threats for the efficacy of pyrethroids insecticides. Knockdown resistance (kdr) mutation, L1014F, is a well-defined mechanism of resistance to pyrethroids and DDT in many insect species. The aim of study was to determine the mechanisms of Insecticide resistance in this species Methods: Specimens of Cx. pipiens, the major vector of West Nile virus, were obtained in Tehran, Iran by collecting larvae from polluted wastewater in Qarchak of Tehran. In 2016 Insecticide susceptibility tests were performed according to WHO methods with deltamethrin 0.05%. We focused on determination of this point mutation in the VGSC gene of Cx. pipiens by Real-time PCR. Results: Our results revealed high levels of resistance to deltamethrin 0.05%. The lethal times i.e. LT50 and LT90 for deltamethrin were 2.1530 and 8.5117 h respectively. The result of Real-time PCR confirmed the presence of resistant genotype in all the members of tested population. This study is the first report on kdr genotyping of Cx. pipiens from Tehran and our results on the VGSC gene in position L1014F confirmed the TTA to TTT nucleotide change. Conclusion: This finding will provide a clue for management of insecticide resistance in mosquito which are vectors of arboviruses and decision for replacement of novel approach for vector control.

scholarly journals Performance Characteristics of an In-House Assay System Used To Detect West Nile Virus (WNV)-Specific Immunoglobulin M during the 2001 WNV Season in the United States

2003 ◽  
Vol 10 (1) ◽  
pp. 177-179 ◽  
Author(s):  
Harry E. Prince ◽  
Wayne R. Hogrefe
Keyword(s):  
West Nile Virus ◽  
The United States ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Screening Assay ◽  
West Nile ◽  
Elisa System ◽  
Igm Elisa ◽  
Specific Immunoglobulin ◽  
Control And Prevention

ABSTRACT During the 2001 U. S. West Nile virus (WNV) season, 163 specimens were reactive in an in-house WNV-specific immunoglobulin M (IgM) screening enzyme-linked immunosorbent assay (ELISA) and were referred to either the Centers for Disease Control and Prevention or the appropriate state public health laboratory (CDC/SPHL) for additional testing. CDC/SPHL supplied results for 124 specimens that could be further evaluated in-house: 70 specimens were nonreactive in the CDC/SPHL WNV-specific IgM screening assay, and 54 specimens were reactive. These specimens were used to evaluate a modified in-house WNV-specific IgM ELISA that incorporated background subtraction to identify nonspecific reactivity and thus improve assay specificity. Of the 70 CDC/SPHL nonreactive samples, 49 (70%) were nonreactive in the modified ELISA; of the 54 CDC/SPHL reactive samples, 51 (94%) were reactive in the modified ELISA. Confirmatory studies performed by CDC/SPHL indicated that 38 CDC/SPHL screen-reactive specimens represented true WNV infection; all 38 specimens were reactive in the modified in-house WNV-specific IgM ELISA. These findings demonstrate that an in-house ELISA system for WNV-specific IgM effectively identifies patients with WNV infection.

scholarly journals Serological Evaluation of Suspected West Nile Virus Human Cases following Its Introduction during a Dengue Outbreak in Puerto Rico in 2007

2011 ◽  
Vol 18 (6) ◽  
pp. 978-983 ◽  
Author(s):  
Elizabeth Hunsperger ◽  
Manuela Beltran ◽  
Luz Nereida Acosta ◽  
Jorge Jordan-Munoz ◽  
Jomil Torres ◽  
...  
Keyword(s):  
Puerto Rico ◽  
West Nile Virus ◽  
Nonstructural Protein ◽  
Diagnostic Testing ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rt Pcr ◽  
Serum Samples ◽  
West Nile ◽  
Nonstructural Protein 1 ◽  
Testing Algorithm

ABSTRACTA laboratory testing algorithm was evaluated to confirm West Nile virus (WNV) infection in human serum following the introduction of the virus in Puerto Rico in 2007. This testing algorithm used two standard diagnostic assays, the IgM antibody capture enzyme-linked immunosorbent assay (MAC ELISA) and real-time reverse transcriptase PCR (RT-PCR), along with two nonconventional assays, the nonstructural protein 1 (NS1) ELISA and a 90%-plaque-reduction neutralization test (PRNT90) with IgG depletion for dengue virus (DENV) and WNV. A total of 2,321 serum samples from suspected WNV human cases were submitted for testing. Approximately one-third (867, 37%) were cross-reactive for DENV and WNV by MAC ELISA and had negative RT-PCR results for both viruses. Of a subset of 43 samples tested, 31 (72%) of these cases were identified as positive for DENV in the PRNT90with IgG depletion and 8 (19%) were positive in the DENV NS1 antigen ELISA. These two assays combined differentiated 36 (84%) of the samples that could not be diagnosed using the standard diagnostic testing methods.

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