Foot-and-mouth disease (FMD), caused by FMD virus (FMDV), is a highly contagious and economically devastating viral disease of cloven-hoofed animals worldwide. In this study, the coexpression of small ubiquitin-like modifier (SUMO)–fused capsid proteins of FMDV serotype O by single plasmid in Escherichia coli was achieved with an optimal tandem permutation (VP0–VP3–VP1), showing a protein yield close to 1:1:1. After SUMO removal at a low level of protease activity (5 units), the assembled FMDV virus-like particles (VLPs) could expose multiple epitopes and have a size similar to the naive FMDV. Immunization of pigs with the FMDV VLPs could induce FMDV-specific humoral and cellular immune responses effectively, in a dose-dependent manner. These data suggested that the stable FMDV VLPs with multiple epitope exposure were effective for the induction of an immune response in pigs, which laid a foundation for the further development of the FMDV subunit vaccine.

由口蹄疫病毒（FMDV）引起的口蹄疫（FMD）是一种高度传染性且在经济上具有破坏力的偶蹄类动物的病毒性疾病。在这项研究中，FMDV血清型O的小泛素样修饰子（SUMO）融合衣壳蛋白在单个质粒中的共表达大肠杆菌最佳串联置换（VP0–VP3–VP1）可以实现，显示蛋白质产量接近1：1：1。在以低水平的蛋白酶活性（5个单位）去除SUMO之后，组装的FMDV病毒样颗粒（VLP）可以暴露多个表位，其大小与原始FMDV相似。用FMDV VLP免疫猪可以以剂量依赖的方式有效诱导FMDV特异性的体液和细胞免疫反应。这些数据表明具有多个表位暴露的稳定的FMDV VLPs可有效诱导猪的免疫反应，为进一步开发FMDV亚单位疫苗奠定了基础。