Mu Suyu, Sun Shiqi, Dong Hu, Bai Manyuan, Zhang Yun, Teng Zhidong, Ren Mei, Yin Shuanghui, Guo Huichen
Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China.
College of Animal Science, Yangtze University, Jingzhou 434025, China.
Vaccines (Basel). 2020 Sep 15;8(3):532. doi: 10.3390/vaccines8030532.
Senecavirus A (SVA) is the pathogen that has recently caused porcine idiopathic vesicular disease (PIVD). The clinical symptoms of PIVD are similar to those of acute foot-and-mouth disease and also can result in the death of newborn piglets, thus entailing economic losses. Vaccine immunization is the most effective way to prevent and control SVA. Among all SVA vaccines reported, only the SVA inactivated vaccine has been successfully developed. However, to ensure the elimination of this pathogen, safer and more effective vaccines are urgently required. A virus-like particles (VLPs)-based vaccine is probably the best alternative to inactivated vaccine. To develop an SVA VLPs vaccine and evaluate its immune effect, a prokaryotic expression system was used to produce SVA capsid protein and assemble VLPs. The VLPs were characterized by affinity chromatography, sucrose density gradient centrifugation, ZetaSizer and transmission electron microscopy. Meanwhile, the SVA CH-HB-2017 strain was used to infect pigs and to determine infection routes and dose. Experimental pigs were then immunized with the SVA VLPs vaccine emulsified in an ISA 201 adjuvant. The results showed that the VLPs vaccine induced neutralizing and specific antibodies at similar levels as an inactivated SVA vaccine after immunization. The level of INF-γ induced by the VLPs vaccine gradually decreased-similar to that of inactivated vaccine. These results indicated that VLPs vaccine may simultaneously cause both cellular and humoral immune responses. Importantly, after the challenge, the VLPs vaccine provided similar levels of protection as the inactivated SVA vaccine. In this study, we successfully obtained novel SVA VLPs and confirmed their highly immunogenicity, thus providing a superior candidate vaccine for defense and elimination of SVA, compared to the inactivated vaccine.
A组赛内卡病毒（SVA）是近期引发猪特发性水疱病（PIVD）的病原体。PIVD的临床症状与急性口蹄疫相似，还可导致新生仔猪死亡，从而造成经济损失。疫苗免疫是预防和控制SVA的最有效方法。在所有已报道的SVA疫苗中，只有SVA灭活疫苗成功研发。然而，为确保消除这种病原体，迫切需要更安全、更有效的疫苗。基于病毒样颗粒（VLPs）的疫苗可能是灭活疫苗的最佳替代品。为研发SVA VLPs疫苗并评估其免疫效果，采用原核表达系统生产SVA衣壳蛋白并组装VLPs。通过亲和层析、蔗糖密度梯度离心、Zeta电位分析仪和透射电子显微镜对VLPs进行表征。同时，使用SVA CH-HB-2017毒株感染猪，确定感染途径和剂量。然后用在ISA 201佐剂中乳化的SVA VLPs疫苗对实验猪进行免疫。结果表明，VLPs疫苗免疫后诱导的中和抗体和特异性抗体水平与灭活SVA疫苗相似。VLPs疫苗诱导的INF-γ水平逐渐下降，与灭活疫苗相似。这些结果表明，VLPs疫苗可能同时引发细胞免疫和体液免疫反应。重要的是，攻毒后，VLPs疫苗提供的保护水平与灭活SVA疫苗相似。在本研究中，我们成功获得了新型SVA VLPs，并证实了其高度免疫原性，因此与灭活疫苗相比，为防御和消除SVA提供了一种更优的候选疫苗。
