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. 2012;7(2):e31434. doi: 10.1371/journal.pone.0031434. Epub 2012 Feb 9.
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.
西尼罗河病毒（WNV）是一种通过蚊子传播的黄病毒，主要感染鸟类，但偶尔也会感染人类和马匹。某些鸟类，包括乌鸦、麻雀、鹅、蓝松鸦和渡鸦，被认为是对 WNV 高度易感的宿主。WNV 的非结构蛋白 1（NS1）在动物感染过程中可以引发保护性免疫反应，包括 NS1 反应性抗体。NS1 的抗原性表明，NS1 反应性抗体可以为血清学诊断试剂提供基础。为了进一步确定用于诊断的血清学试剂，需要确定 NS1 中宿主免疫反应靶向的抗原性位点，并定义单个抗原性位点的潜在诊断价值。本研究描述了使用禽源 WNV NS1 抗血清全面绘制 WNV NS1 常见免疫显性线性 B 细胞表位的情况。我们筛选了用纯化 NS1 免疫的鸡、鸭和鹅的抗血清，以检测其对覆盖整个 WNV NS1 的 35 个部分重叠肽的反应性。本研究分别鉴定出了鸡、鸭和鹅抗体反应识别的 12、9 和 6 个肽表位。三个表位（NS1-3、14 和 24）被三种禽类的免疫诱导抗体识别。我们还发现 NS1-3 和 24 是 WNV 特异性表位，而 NS1-14 表位在日本脑炎病毒（JEV）血清型复合物病毒的 NS1 序列衍生的多肽中，与禽源 WNV NS1 抗血清的反应性一致，这表明该表位是保守的。进一步分析表明，这三个共同的多肽表位不被禽流感病毒（AIV）、新城疫病毒（NDV）、鸭瘟病毒（DPV）和鹅细小病毒（GPV）抗血清中的抗体识别。本研究中获得的知识和试剂在 WNV 和 JEV 血清型复合物其他病毒的差异诊断方法和亚单位疫苗开发方面具有潜在的应用价值。
