Comprehensive Mapping of Common Immunodominant Epitopes in the West Nile Virus Nonstructural Protein 1 Recognized by Avian Antibody Responses

The Key Laboratory of Veterinary Public Health, Harbin Veterinary Research Institute, Ministry of Agriculture, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China.
PLoS ONE (Impact Factor: 3.23). 02/2012; 7(2):e31434. DOI: 10.1371/journal.pone.0031434
Source: PubMed


West Nile virus (WNV) is a mosquito-borne flavivirus that primarily infects birds but occasionally infects humans and horses. Certain species of birds, including crows, house sparrows, geese, blue jays and ravens, are considered highly susceptible hosts to WNV. The nonstructural protein 1 (NS1) of WNV can elicit protective immune responses, including NS1-reactive antibodies, during infection of animals. The antigenicity of NS1 suggests that NS1-reactive antibodies could provide a basis for serological diagnostic reagents. To further define serological reagents for diagnostic use, the antigenic sites in NS1 that are targeted by host immune responses need to be identified and the potential diagnostic value of individual antigenic sites also needs to be defined. The present study describes comprehensive mapping of common immunodominant linear B-cell epitopes in the WNV NS1 using avian WNV NS1 antisera. We screened antisera from chickens, ducks and geese immunized with purified NS1 for reactivity against 35 partially overlapping peptides covering the entire WNV NS1. This study identified twelve, nine and six peptide epitopes recognized by chicken, duck and goose antibody responses, respectively. Three epitopes (NS1-3, 14 and 24) were recognized by antibodies elicited by immunization in all three avian species tested. We also found that NS1-3 and 24 were WNV-specific epitopes, whereas the NS1-14 epitope was conserved among the Japanese encephalitis virus (JEV) serocomplex viruses based on the reactivity of avian WNV NS1 antisera against polypeptides derived from the NS1 sequences of viruses of the JEV serocomplex. Further analysis showed that the three common polypeptide epitopes were not recognized by antibodies in Avian Influenza Virus (AIV), Newcastle Disease Virus (NDV), Duck Plague Virus (DPV) and Goose Parvovirus (GPV) antisera. The knowledge and reagents generated in this study have potential applications in differential diagnostic approaches and subunit vaccines development for WNV and other viruses of the JEV serocomplex.

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    • "Multiple potential B-cell epitopes in the E (Apt et al., 2006;Brien et al., 2010;Gromowski et al., 2008;Lin et al., 2012;SukupolviPetty et al., 2007), NS1 (Steidel et al., 2012;Wu et al., 2003), NS4a and C (Anandarao et al., 2005) proteins for DENV have been well characterized. Prediction and analyses of B-cell epitopes of other flaviviruses have also focused on E, NS1 and NS5 proteins (Chiou et al., 2012;Hall et al., 2009;Sun et al., 2012). Although the importance of prM antibodies has been well demonstrated, only a few linear immunogenic determinants in DENV prM protein have ever been identified (Dejnirattisai et al., 2010;Vázquez et al., 2002). "
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