Wang Xinjie, Zhao Qin, Dang Lu, Sun Yani, Gao Jiming, Liu Baoyuan, Syed Shahid Faraz, Tao Hu, Zhang Gaiping, Luo Jianxun, Zhou En-Min
Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, China Ministry of Agriculture, Yangling, Shaanxi, China.
Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China.
J Virol. 2015 May;89(10):5491-501. doi: 10.1128/JVI.00107-15. Epub 2015 Mar 4.
Antisera raised against the avian hepatitis E virus (HEV) capsid protein are cross-reactive with human and swine HEV capsid proteins. In this study, two monoclonal antibodies (MAbs) against the avian HEV capsid protein, namely, 3E8 and 1B5, were shown to cross-react with the swine HEV capsid protein. The motifs involved in binding both MAbs were identified and characterized using phage display biopanning, peptide synthesis, and truncated or mutated protein expression, along with indirect enzyme-linked immunosorbent assay (ELISA) and Western blotting. The results showed that the I/VPHD motif is a necessary core sequence and that P and H are two key amino acids for recognition by MAb 3E8. The VKLYM/TS motif is the minimal amino acid sequence necessary for recognition by MAb 1B5. Cross-reactivity between the two epitopes and antibodies against avian, swine, and human HEVs in sera showed that both epitopes are common to avian, swine, and human HEVs. In addition, amino acid sequence alignment of the capsid proteins revealed that the key motifs of both novel epitopes are the same in HEVs from different animal species, predicting that they may be common to HEV isolates from boars, rabbits, rats, ferrets, mongooses, deer, and camels as well. Protein modeling analysis showed that both epitopes are at least partially exposed on the surface of the HEV capsid protein. Protective capacity analysis demonstrated that the two epitopes are nonprotective against avian HEV infection in chickens. Collectively, these studies characterize two novel linear B-cell epitopes common to avian, swine, and human HEVs, which furthers the understanding of HEV capsid protein antigenic structure.
More and more evidence indicates that the host range diversity of hepatitis E virus (HEV) is a global public health concern. A better understanding of the antigenic structure of the HEV capsid protein may improve disease diagnosis and prevention. In this study, binding site mapping and localization as well as the antigenic biology of two novel linear B-cell epitopes common to several different species of HEV were characterized. These findings partially reveal the antigenic structure of the HEV capsid protein and provide potential applications for the development of diagnostics and interventions for HEV infection.
针对禽戊型肝炎病毒（HEV）衣壳蛋白产生的抗血清与人及猪的HEV衣壳蛋白存在交叉反应。在本研究中，两种针对禽HEV衣壳蛋白的单克隆抗体（MAb），即3E8和1B5，被证明与猪HEV衣壳蛋白存在交叉反应。通过噬菌体展示生物淘选、肽合成、截短或突变蛋白表达，以及间接酶联免疫吸附测定（ELISA）和蛋白质印迹法，鉴定并表征了与这两种单克隆抗体结合相关的基序。结果表明，I/VPHD基序是一个必需的核心序列，P和H是单克隆抗体3E8识别的两个关键氨基酸。VKLYM/TS基序是单克隆抗体1B5识别所需的最小氨基酸序列。两种表位与血清中针对禽、猪和人HEV的抗体之间的交叉反应表明，这两种表位在禽、猪和人HEV中是共有的。此外，衣壳蛋白的氨基酸序列比对显示，这两种新表位的关键基序在来自不同动物物种的HEV中是相同的，预测它们可能也存在于来自野猪、兔子、大鼠、雪貂、獴、鹿和骆驼的HEV分离株中。蛋白质建模分析表明，这两种表位至少部分暴露在HEV衣壳蛋白表面。保护能力分析表明，这两种表位对鸡的禽HEV感染没有保护作用。总体而言，这些研究表征了禽、猪和人HEV共有的两种新的线性B细胞表位，这进一步加深了对HEV衣壳蛋白抗原结构的理解。
越来越多的证据表明，戊型肝炎病毒（HEV）的宿主范围多样性是一个全球公共卫生问题。更好地了解HEV衣壳蛋白的抗原结构可能会改善疾病的诊断和预防。在本研究中，对几种不同物种的HEV共有的两种新的线性B细胞表位的结合位点定位以及抗原生物学特性进行了表征。这些发现部分揭示了HEV衣壳蛋白的抗原结构，并为开发HEV感染的诊断方法和干预措施提供了潜在应用。
