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；改善的粘膜免疫反应；以及易于管理。虽然这种疫苗已经在动物模型和人体试验中被证明是免疫原性的，但关于这种免疫策略的保护效果的数据很少。同样，与口服由更传统的表达系统产生的重组蛋白相比，关于口服转基因植物材料的相对免疫原性和有效性的信息很少。由于在抗原稳定性(由植物细胞的存在)和肠道中的免疫处理方面的感知差异，植物疫苗被假设为优于口服给药。这项研究建议在动物系统中测试这一假设，在动物系统中，保护性免疫原被明确定义。被研究的系统是豚鼠巨细胞病毒(GPCMV)模型，蛋白是糖蛋白B(GB)蛋白。选择这种蛋白质的理由是，这种蛋白质在疫苗介导的预防CMV疾病方面明显有效，从而为测试口服疫苗的“概念证明”提供了宝贵的机会。在这个模型中，我们已经证明，当在杆状病毒中表达为佐剂亚单位疫苗时，针对GB蛋白产生的体液反应在保护母体-胎盘-胎儿单位方面至关重要。此外，由于CMV感染通常是在粘膜表面获得的，因此有必要对口服疫苗在粘膜部位接种重组GB疫苗进行评估。利用农杆菌介导法在转基因植物表达系统中进行重组，我们成功地获得了转GPCMV GB基因的拟南芥植株，该转基因植株将被用来口服佐剂(霍乱毒素B)免疫豚鼠，然后在孕期攻击GPCMV。口服疫苗接种也将用杆状病毒纯化的GB进行。我们将验证这样一种假设，即通过口服途径接种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。将对该疫苗的免疫原性和对先天性感染和疾病的保护效果进行评估。这些研究将推动作为重要公共卫生优先事项的巨细胞病毒疫苗领域的发展。此外，这些研究将提供有关口服转基因植物疫苗潜在效力的数据，这一概念受到的效力分析相对较少。基于gB是豚鼠CMV模型中的关键免疫原的理论，与用其他方法纯化的蛋白质口服免疫相比，有一个令人信服的理由将其作为口服植物疫苗进行评估。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.