National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Life Sciences, Xiamen University, Xiamen 361102, China.
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China.
Vaccine. 2018 Apr 12;36(16):2104-2111. doi: 10.1016/j.vaccine.2018.03.005. Epub 2018 Mar 12.
Hepatitis E virus (HEV) is associated with acute hepatitis disease. Numerous truncated HEV capsid proteins have been successfully expressed using different expression systems. Among these, p495, a protein truncated at its N- and C-termini by 111 and 54 amino acids (aa), respectively (HEV ORF2 aa 112-606) can self-assemble into T = 1 virus-like particles (VLPs) when expressed by insect cells. A shorter p239 (aa 368-606) protein is a particulate antigen that we have previously used in our commercialized HEV vaccine, Hecolin. Here, we sought to express p495 in its soluble form (named Ep495) in E. coli and in baculovirus-infected Tn5 insect cells (named BTp495) as a back-to-back control. Characterization of p495 particles derived from these two expression systems showed similarities in particle size, morphology, and sedimentation coefficient. Antigenicity assays using a panel of anti-HEV monoclonal antibodies also showed similar strong reactivities for Ep495 and BTp495, as well as similar binding profiles that were congruent with p239. Mouse immunization results showed that Ep495 particles had comparable immunogenicity with that of BTp495 VLPs, as well as p239. Overall, our findings suggest that p495 particles produced in E. coli are ideal for the development of next-generation prophylactic vaccines against hepatitis E.
戊型肝炎病毒（HEV）与急性肝炎疾病有关。已经使用不同的表达系统成功表达了许多截短的 HEV 衣壳蛋白。其中，p495 是一种在 N 端和 C 端分别截断 111 和 54 个氨基酸（aa）的蛋白（HEV ORF2 aa 112-606），当在昆虫细胞中表达时，可以自组装成 T=1 病毒样颗粒（VLPs）。较短的 p239（aa 368-606）蛋白是一种颗粒状抗原，我们之前在商业化的 HEV 疫苗 Hecolin 中使用过。在这里，我们试图在大肠杆菌中以可溶性形式表达 p495（命名为 Ep495），并在杆状病毒感染的 Tn5 昆虫细胞（命名为 BTp495）中表达，作为对照。从这两种表达系统中获得的 p495 颗粒的特性分析表明，颗粒大小、形态和沉降系数相似。使用一组抗 HEV 单克隆抗体进行的抗原性检测也表明，Ep495 和 BTp495 具有相似的强反应性，以及与 p239 一致的结合谱。小鼠免疫结果表明，Ep495 颗粒与 BTp495 VLPs 以及 p239 具有相当的免疫原性。总的来说，我们的研究结果表明，在大肠杆菌中产生的 p495 颗粒非常适合开发针对戊型肝炎的下一代预防性疫苗。
