Biodesign Institute and School of Life Sciences, Arizona State University, Tempe, Arizona, USA.
Plant Biotechnol J. 2011 Sep;9(7):807-16. doi: 10.1111/j.1467-7652.2011.00593.x. Epub 2011 Feb 1.
Filoviruses (Ebola and Marburg viruses) cause severe and often fatal haemorrhagic fever in humans and non-human primates. The US Centers for Disease Control identifies Ebola and Marburg viruses as 'category A' pathogens (defined as posing a risk to national security as bioterrorism agents), which has lead to a search for vaccines that could prevent the disease. Because the use of such vaccines would be in the service of public health, the cost of production is an important component of their development. The use of plant biotechnology is one possible way to cost-effectively produce subunit vaccines. In this work, a geminiviral replicon system was used to produce an Ebola immune complex (EIC) in Nicotiana benthamiana. Ebola glycoprotein (GP1) was fused at the C-terminus of the heavy chain of humanized 6D8 IgG monoclonal antibody, which specifically binds to a linear epitope on GP1. Co-expression of the GP1-heavy chain fusion and the 6D8 light chain using a geminiviral vector in leaves of N. benthamiana produced assembled immunoglobulin, which was purified by ammonium sulphate precipitation and protein G affinity chromatography. Immune complex formation was confirmed by assays to show that the recombinant protein bound the complement factor C1q. Size measurements of purified recombinant protein by dynamic light scattering and size-exclusion chromatography also indicated complex formation. Subcutaneous immunization of BALB/C mice with purified EIC resulted in anti-Ebola virus antibody production at levels comparable to those obtained with a GP1 virus-like particle. These results show excellent potential for a plant-expressed EIC as a human vaccine.
丝状病毒(埃博拉病毒和马尔堡病毒)可引起人类和非人类灵长类动物严重且常常致命的出血热。美国疾病控制与预防中心将埃博拉病毒和马尔堡病毒确定为“类别 A”病原体(定义为作为生物恐怖主义制剂对国家安全构成威胁),这导致人们寻找可预防该疾病的疫苗。由于此类疫苗的使用将服务于公共卫生,因此生产成本是其开发的一个重要组成部分。植物生物技术的使用是一种可以有效生产亚单位疫苗的方法。在这项工作中,使用双生病毒复制子系统在本氏烟中生产埃博拉免疫复合物(EIC)。埃博拉糖蛋白(GP1)融合到人源化 6D8 IgG 单克隆抗体重链的 C 末端,该抗体特异性结合 GP1 上的线性表位。使用双生病毒载体在 N. benthamiana 的叶片中共表达 GP1-重链融合物和 6D8 轻链,可产生组装的免疫球蛋白,该免疫球蛋白通过硫酸铵沉淀和蛋白 G 亲和层析进行纯化。通过测定证实了重组蛋白结合补体因子 C1q,表明形成了免疫复合物。通过动态光散射和尺寸排阻色谱法对纯化的重组蛋白进行的尺寸测量也表明形成了复合物。用纯化的 EIC 对 BALB/C 小鼠进行皮下免疫接种可产生与使用 GP1 病毒样颗粒获得的水平相当的抗埃博拉病毒抗体。这些结果表明,植物表达的 EIC 作为人类疫苗具有巨大的潜力。