West Nile Virus (WNV)

West Nile Virus Antibody Products by Targets

West Nile Virus Background

West Nile Virus (WNV) is one of the major leading causes of mosquito-borne disease. WNV is most commonly spread to people by the bite of an infected mosquito. Cases of WNV occur during mosquito season, which starts in the summer and continues through fall. There are no vaccines to prevent or medications to treat WNV in people. Fortunately, most people infected with WNV do not feel sick. About 1 in 5 people who are infected develop a fever and other symptoms. About 1 out of 150 infected people develop a serious, sometimes fatal, illness.

Structure and Genome of WNV

WNV is a member of the Flaviviridae family of single-stranded RNA viruses with linear non-segmented genomes. The WNV genome is a positive single stranded RNA of approximately 11000 nucleotides surrounded by an icosahedral nucleocapsid which is contained in a lipid bi-layered envelope. The genome is transcribed as a single polyprotein that is cleaved by host and viral proteases into three structural and seven non-structural proteins, namely capsid (C), premembrane/membrane (prM/M), envelope (E) and non-structural protein 1 (NS1), non-structural protein 2A (NS2A), non-structural protein 2B (NS2B), non-structural protein 3 (NS3), non-structural protein 4A (NS4A), non-structural protein 4B (NS4B), non-structural protein 5 (NS5).

Fig.3 Structure of WNV. (Valiakos, 2013)

Structural Protein Targets

The viral C protein is approximately 30 nm in diameter and consists of C protein dimers, the basic component of nucleocapsids, with the RNA binding domains located at the C- and N- termini separated by a hydrophobic region. The hydrophobic regions of the C dimers form an apolar surface which binds to the inner side of the viral lipid membrane.

prM is the only viral peptide matured by host furin in the trans-Golgi network probably to avoid catastrophic activation of the viral fusion activity in acidic Golgi compartment prior to virion release. prM-E cleavage is inefficient, and many virions are only partially matured. These uncleaved prM would play a role in immune evasion.

The E proteins are organized in 3 domains connected by flexible hinges, domain I (DI), domain II (DII) and domain III (DIII). DI is positioned at the central portion of the protein, linking together the other two domains. DII is a long domain that forms an internal fusion loop which is necessary for flaviviral fusion. DIII is an immunoglobulin (Ig)-like fold that is thought to participate in interactions between virions and host factors associated with virus entry.

Fig.4 RNA genome of WNV and site sites cleaved by host proteases. (Valiakos, 2013)

Popular Non-structural Protein Targets

1. NS1 functions as a cofactor for viral RNA replication and is the only non-structural protein that is secreted in high levels (up to 50 μg/ml) in the serum of WNV infected patients and has been connected with severe disease.
2. NS2A is a component of the viral RNA replication complex that functions in virion assembly and antagonizes the host alpha/beta interferon antiviral response.
3. NS2B is a cofactor required for NS3 proteolytic activity.
4. NS3 displays three enzymatic activities: serine protease, NTPase and RNA helicase. NS3 serine protease, in association with NS2B, performs its autocleavage and cleaves the polyprotein at dibasic sites in the cytoplasm.
5. NS4A regulates the ATPase activity of the NS3 helicase activity and allows NS3 helicase to conserve energy during unwinding.
6. NS4B colocalizes with viral replication complexes and is proved to dissociate NS3 from single-stranded RNA, thereby enabling it to bind to a new dsRNA duplex, consequently enhancing the helicase activity and modulating viral replication.
7. NS5 is the largest and most conserved of flaviviruses proteins. The N-terminal region of NS5 contains an S-adenosyl methionine methyltransferase (MTase) domain and the C-terminal region of NS5 contains a RNA-dependent RNA polymerase which is required for the synthesis of the viral RNA genome.

What Creative Biolabs offers?

In contrast to other RNA viruses, such as human immunodeficiency virus (HIV) and influenza, WNV exhibits a high degree of sequence conservation in its natural reservoir. Such sequence conservation makes WNV a promising target with regard to targeting humoral and cellular immune responses to conserved epitopes. Monoclonal antibody (mAb) has many advantages such as targeting to a single epitope, high specificity, stable passage, large-scale manufacturing and extensive applications in basic research, medical diagnosis, and tumor therapy. Armed with advanced technology, Creative Biolabs now provides anti-WNV mAbs as well as polyclonal antibodies (pAbs) products for research use. We can also provide a full comprehensive suite of secondary antibodies and isotype controls to meet your needs. Flexible customized solutions are available according to customer’s requirements.

Learn more about our ViroAntibody Discovery Services. Please feel free to contact us for more information.

Reference

1. Valiakos, G.; et al. West Nile virus: Basic principles, replication mechanism, immune response and important genetic determinants of virulence. Viral replication. 2013: 43-68.
2. Suthar M S, Diamond M S. West Nile virus infection and immunity. Nat Rev Microbiol. 2013 Feb;11(2):115-28.