Laboratório de Virologia Molecular, Instituto Carlos Chagas, FIOCRUZ-PR, Curitiba, Paraná, Brazil.
Sci Rep. 2017 Nov 24;7(1):16229. doi: 10.1038/s41598-017-16231-6.
Yellow fever is an arboviral disease that causes thousands of deaths every year in Africa and the Americas. However, few commercial diagnostic kits are available. Non-structural protein 1 (NS1) is an early marker of several flavivirus infections and is widely used to diagnose dengue virus (DENV) infection. Nonetheless, little is known about the dynamics of Yellow fever virus (YFV) NS1 expression and secretion, to encourage its use in diagnosis. To tackle this issue, we developed a quantitative NS1-capture ELISA specific for YFV using a monoclonal antibody and recombinant NS1 protein. This test was used to quantify NS1 in mosquito and human cell line cultures infected with vaccine and wild YFV strains. Our results showed that NS1 was detectable in the culture supernatants of both cell lines; however, a higher concentration was maintained as cell-associated rather than secreted into the extracellular milieu. A panel of 73 human samples was used to demonstrate the suitability of YFV NS1 as a diagnostic tool, resulting in 80% sensitivity, 100% specificity, a 100% positive predictive value and a 95.5% negative predictive value compared with RT-PCR. Overall, the developed NS1-capture ELISA showed potential as a promising assay for the detection of early YF infection.
黄热病是一种虫媒病毒病，每年在非洲和美洲导致数千人死亡。然而，可用的商业诊断试剂盒却很少。非结构蛋白 1（NS1）是几种黄病毒感染的早期标志物，广泛用于诊断登革热病毒（DENV）感染。尽管如此，人们对黄热病病毒（YFV）NS1表达和分泌的动态知之甚少，这阻碍了其在诊断中的应用。为了解决这个问题，我们使用单克隆抗体和重组 NS1 蛋白开发了一种针对 YFV 的定量 NS1 捕获 ELISA。该测试用于定量感染疫苗和野生 YFV 株的蚊子和人细胞系培养物中的 NS1。我们的结果表明，NS1 可在两种细胞系的培养上清液中检测到；然而，作为细胞相关物质而不是分泌到细胞外环境中的浓度更高。使用 73 个人类样本的面板证明了 YFV NS1 作为诊断工具的适用性，与 RT-PCR 相比，其灵敏度为 80%，特异性为 100%，阳性预测值为 100%，阴性预测值为 95.5%。总的来说，开发的 NS1 捕获 ELISA 显示出作为检测早期 YF 感染的有前途的检测方法的潜力。
