Joint Center for Infection and Immunity, Guangzhou Institute of Pediatrics, Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China.
Unit of Vaccinology & Antiviral Strategies, CAS Key Laboratory of Molecular Virology & Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.
Viruses. 2018 Jan 30;10(2):58. doi: 10.3390/v10020058.
In recent years, enterovirus D68 (EVD68) has been reported increasingly to be associated with severe respiratory tract infections and acute flaccid myelitis (AFM) in children all over the world. Yet, no effective vaccines or antiviral drugs are currently available for EVD68. Although several experimental animal models have been developed, immunogenicity and protective efficacy of inactivated EVD68 vaccines has not been fully evaluated. To promote the development of vaccines, we established an Institute of Cancer Research (ICR) suckling mouse model of EVD68 infection in this study. The results showed that ICR neonatal mice up to about nine days of age were susceptible to infection with EVD68 clinical strain US/MO/14-18947 by intraperitoneal injection. The infected mice exhibited progressive limb paralysis prior to death and the mortality of mice was age- and virus dose-dependent. Tissue viral load analysis showed that limb muscle and spinal cord were the major sites of viral replication. Moreover, histopathologic examination revealed the severe necrosis of the limb and juxtaspinal muscles, suggesting that US/MO/14-18947 has a strong tropism toward muscle tissues. Additionally, β-propiolactone-inactivated EVD68 vaccine showed high purity and quality and induced robust EVD68-specific neutralizing antibody responses in adult mice. Importantly, results from both antisera transfer and maternal immunization experiments clearly showed that inactivated EVD68 vaccine was able to protect against lethal viral infection in the mouse model. In short, these results demonstrate the successful establishment of the mouse model of EVD68 infection for evaluating candidate vaccines against EVD68 and also provide important information for the development of inactivated virus-based EVD68 vaccines.
近年来，肠道病毒 D68（EVD68）在全球范围内被报道与儿童严重呼吸道感染和急性弛缓性脊髓炎（AFM）越来越相关。然而，目前尚无针对 EVD68 的有效疫苗或抗病毒药物。尽管已经开发了几种实验动物模型，但灭活 EVD68 疫苗的免疫原性和保护效力尚未得到充分评估。为了促进疫苗的发展，我们在本研究中建立了 EVD68 感染的 ICR 乳鼠模型。结果表明，多达约 9 天大的 ICR 新生小鼠通过腹腔注射易感染 EVD68 临床株 US/MO/14-18947。感染的小鼠在死亡前表现出进行性肢体瘫痪，并且小鼠的死亡率与年龄和病毒剂量有关。组织病毒载量分析表明，肢体肌肉和脊髓是病毒复制的主要部位。此外，组织病理学检查显示肢体和脊柱旁肌肉严重坏死，表明 US/MO/14-18947对肌肉组织具有很强的嗜性。此外，β-丙内酯灭活的 EVD68 疫苗表现出高纯度和高质量，并在成年小鼠中诱导出强烈的 EVD68 特异性中和抗体反应。重要的是，来自抗血清转移和母体免疫实验的结果清楚地表明，灭活的 EVD68 疫苗能够保护小鼠免受致命的病毒感染。总之，这些结果表明成功建立了用于评估针对 EVD68 的候选疫苗的 EVD68 感染小鼠模型，并为开发基于灭活病毒的 EVD68 疫苗提供了重要信息。
