BACKGROUND Prophylactic vaccines are critical in preventing hand, foot, and mouth disease (HFMD) primarily caused by human enterovirus 71 (EV71) infection. Children aged less than 5 years are especially susceptible to EV71 infections. In addition to the development of vaccines containing the inactivated virus, those containing virus-like particles (VLPs) with repeated antigens also constitute an effective preventive strategy for EV71 infections, with safety and productivity advantages. We previously developed a fusion protein composed with truncated peptides of the EV71 capsid protein, which assembled into spherical particles. This study aimed to assess the immunoprotective effects of this fusion protein as a vaccine candidate in a mouse model of EV71 infection. METHODS To evaluate the protective effect of fusion protein vaccine candidate, neonatal mice born by immunized female mice, as well as normal neonatal mice immunized twice were infected with EV71 virus. Whereafter, the survival rates, clinical scores and viral loads were measured. RESULTS The high dosage and booster immunization helped induce specific serum antibodies with high neutralization titers, which were transferred to neonatal mice, thereby facilitating effective resistance towards EV71 infection. An active immune response was also observed in neonatal mice which generated following immunization. CONCLUSIONS The present results suggest that this fusion protein is a suitable vaccine candidate in treating EV71 infections.

中文翻译：

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从人肠病毒71的截短肽产生的融合蛋白候选疫苗进行免疫可以保护小鼠免受致命性肠病毒71感染。

背景技术预防性疫苗对于预防主要由人肠病毒71（EV71）感染引起的手足口病（HFMD）至关重要。小于5岁的儿童特别容易感染EV71。除了开发含有灭活病毒的疫苗外，含有具有重复抗原的病毒样颗粒（VLP）的疫苗也构成了EV71感染的有效预防策略，具有安全性和生产率优势。我们之前开发了一种融合蛋白，该蛋白由EV71衣壳蛋白的截短肽组成，并组装成球形颗粒。这项研究旨在评估这种融合蛋白作为候选疫苗在EV71感染小鼠模型中的免疫保护作用。方法为了评估融合蛋白疫苗候选物的保护作用，免疫雌性小鼠所生的新生小鼠以及免疫两次的正常新生小鼠都被EV71病毒感染。之后，测量存活率，临床评分和病毒载量。结果高剂量和加强免疫有助于诱导高中和滴度的特异性血清抗体，并将其转移至新生小鼠，从而促进对EV71感染的有效抵抗。在免疫后产生的新生小鼠中也观察到了主动免疫反应。结论目前的结果表明，该融合蛋白是治疗EV71感染的合适的候选疫苗。结果高剂量和加强免疫有助于诱导高中和滴度的特异性血清抗体，并将其转移至新生小鼠，从而促进对EV71感染的有效抵抗。在免疫后产生的新生小鼠中也观察到了主动免疫反应。结论目前的结果表明，该融合蛋白是治疗EV71感染的合适的候选疫苗。结果高剂量和加强免疫有助于诱导高中和滴度的特异性血清抗体，并将其转移至新生小鼠，从而促进对EV71感染的有效抵抗。在免疫后产生的新生小鼠中也观察到了主动免疫反应。结论目前的结果表明，该融合蛋白是治疗EV71感染的合适的候选疫苗。