Transgenic Plant-Derived CMV Glycoprotein B Vaccine

描述（申请人提供）：近年来推广的一种创新疫苗策略是口服免疫的概念，使用转基因植物作为疫苗。转基因植物疫苗的基本原理是基于这样的疫苗的大规模生产的潜力;较低的费用;改善粘膜免疫应答;和易于管理。尽管这些疫苗在动物模型和人体试验中显示出免疫原性，但关于这种免疫策略的保护效力的数据很少。类似地，与口服施用由更传统的表达系统产生的重组蛋白相比，口服施用转基因植物材料后的相对免疫原性和功效的信息很少。由于抗原稳定性（由植物细胞孔的存在赋予）和肠道中的免疫加工的感知差异，植物疫苗被假设为上级口服给药。本研究提出在保护性免疫原明确的动物系统中检验这一假设。待研究的系统是豚鼠巨细胞病毒（GPCMV）模型，蛋白质是糖蛋白B（gB）蛋白。选择这种蛋白的基本原理是，这种蛋白在疫苗介导的抗CMV疾病的保护中明显有效，从而为测试口服疫苗接种的“概念验证”提供了宝贵的机会。在这个模型中，我们已经表明，产生的体液反应对gB蛋白，当表达作为佐剂的亚单位疫苗在杆状病毒，是至关重要的保护母-胎盘-胎儿单位。此外，由于CMV感染通常是在粘膜表面获得的，因此需要对在粘膜部位口服疫苗给予重组gB疫苗进行评价。利用根癌农杆菌介导的重组转基因植物表达系统，我们已经设计了GPCMV gB，这将被用来免疫豚鼠，口服，佐剂（霍乱毒素B），然后在怀孕期间的GPCMV攻击转基因拟南芥植物。还将使用杆状病毒纯化gB进行口服疫苗接种。我们将检验这样一个假设，即当通过口服途径给药时，植物来源的疫苗比杆状病毒来源的蛋白更具免疫原性和保护性。将评价该疫苗的免疫原性和对先天性感染和疾病的保护效力。这些研究将推进HCMV疫苗领域，这是一个重要的公共卫生优先事项。此外，这些研究将提供关于口服转基因植物疫苗接种的潜在功效的数据，这是一个相对较少进行功效分析的概念。基于gB是豚鼠CMV模型中的关键免疫原的原理，与通过其他方法纯化的蛋白质口服免疫相比，有令人信服的原理将该蛋白质作为口服植物疫苗进行评价。这些研究将推动植物和CMV疫苗领域的发展。

DESCRIPTION (provided by applicant): An innovative vaccine strategy that has been promoted in recent years is the concept of oral immunization, using transgenic plants as vaccines. The rationale for transgenic plant vaccines is based on the potential for mass productive of such vaccines; lower expense; improved mucosal immune responses; and ease of administration. Although such vaccines have been shown in animal models and in human trials to be immunogenic, there is very little data about the protective efficacy of this immunization strategy. There is similarly little information about the relative immunogenicity and efficacy of following oral administration of transgenic plant material compared with oral administration of recombinant proteins generated by more traditional expression systems. Because of perceived differences in antigen stability (conferred by the presence of a plant cell well) and immunologic processing in the gut, plant vaccines are hypothesized to be superior for oral administration. This study proposes to test this hypothesis in an animal system in which the protective immunogen is well defined. The system to be studied is the guinea pig cytomegalovirus (GPCMV) model, and the protein is the glycoprotein B (gB) protein. The rationale for choosing this protein is that this protein is clearly effective in vaccine-mediated protection against CMV disease, thus providing a valuable opportunity for testing "proof of concept" of oral vaccination. In this model, we have shown that humoral responses generated against the gB protein, when expressed as an adjuvanted subunit vaccine in baculovirus, are critical in protection of the maternal-placental-fetal unit. Furthermore, since CMV infections are typically acquired at mucosal surfaces, evaluation of recombinant gB vaccine administered at an oral vaccine, at a mucosal site, warrants investigation. Using Agrobacteria tumefaciens-mediated recombination in transgenic plant expression systems, we have engineered an Arabidopsis plant transgenic for GPCMV gB, which will be utilized to immunize guinea pigs, orally, with adjuvant (cholera toxin B), followed by GPCMV challenge during pregnancy. Oral vaccination will also be conducted with baculovirus-purified gB. We will test the hypothesis that plant-derived vaccine is more immunogenic and protective than baculovirus-derived protein when administered by an oral route. The immunogenicity and protective efficacy against congenital infection and disease of this vaccine will be evaluated. These studies will advance the field of HCMV vaccines, an important public health priority. Moreover, these studies will provide data regarding the potential efficacy of oral transgenic plant vaccination, a concept which has been subjected to relatively few efficacy analyses. Based on the rationale that gB is a key immunogen in the CMV model in guinea pigs, there is a compelling rationale to evaluate this protein as an oral plant-based vaccine, compared to oral immunization with proteins purified by other approaches. These studies will advance the fields of plant and CMV vaccines.