Production of OspA in rice for the control of Lyme Disease

描述(由申请人提供)：由于基于外表面蛋白A(OspA)的可注射疫苗的市场接受度和安全性，目前还没有针对由伯氏杆菌引起的莱姆病的人类疫苗。保护人类免受莱姆病侵袭的另一种方法是给病源接种疫苗，以减少或消除媒介蜱中的伯氏杆菌，从而抑制地方性传播，防止疾病传播给人类。许多研究表明，口服OspA疫苗成功地接种了啮齿动物，并降低了扁虱的感染率。在目前的提案中，我们计划开发一种新的方法来预防人类接触莱姆病螺旋体，方法是使用来自大米的蓄水池靶向疫苗(RTV)显著降低扁虱媒介肩部硬蜱的感染率。我们将从我们的第一代转化子中培育出稳定的纯合子水稻品系，这些品系可以用于生产RoSPA，用于本研究以及未来的大规模生产和社区范围的分配。我们将制定RoSPA，并在实验室动物身上测试水库靶向疫苗的有效性。最后，我们将进行RoSPA的纯化和体外鉴定，以用于未来监管部门对基于RoSPA的疫苗的批准。由于米粒自然是许多有望作为伯氏杆菌宿主的动物的食物，在大米中生产RoSPA比其他表达系统具有明显的优势，更重要的是，以大米为基础的RoSPA将对人类、动物和环境提供极好的安全性。公共卫生相关性：莱姆病是由携带伯氏杆菌的扁虱叮咬引起的，在美国许多地区是对人类健康的主要威胁。先前的研究表明，通过给啮齿动物蓄水池接种伯氏芽孢杆菌外表面蛋白A，可以极大地降低勃氏芽孢杆菌在硬蜱中的流行率。开发一种负担得起的口服疫苗将使动物水库能够大规模接种疫苗，并降低将莱姆病传播给人类的风险。

DESCRIPTION (provided by applicant): A vaccine for humans against Lyme disease caused by B. burgdorferi is currently not available due to market acceptance and safety of an injectable vaccine based on outer surface protein A (OspA). An alternate approach to protecting humans from Lyme disease is to vaccinate the disease reservoirs to reduce or eliminate B. burgdorferi from vector ticks, thereby suppressing enzootic transmission and preventing them from passing the disease to humans. A number of studies have shown that orally administered OspA based vaccines successfully vaccinate rodents, and reduce prevalence of infection in ticks. In the present proposal, we plan to develop a novel approach for preventing human exposure to Lyme disease spirochetes by significantly reducing infection prevalence in the tick vector, Ixodes scapularis, using reservoir targeted vaccines (RTVs) derived from rice. We will develop stable homozygous rice lines from our first generation transformants that can be used to produce rOspA for the present study and for future large scale production and community-wide distribution. We will formulate the rOspA and test the effectiveness of a reservoir targeting vaccine in laboratory animals. Finally, we will conduct purification and in vitro characterization of rOspA for use in future regulatory approval of rOspA based vaccines. Since rice grain is naturally a food of many of the animals expected to serve as B. burgdorferi reservoirs, producing rOspA in rice provides a distinct advantage over other expression systems and more importantly, rice-based rOspA will offer an excellent safety profile to humans, animals and the environment. Public Health Relevance: Lyme disease, caused by a bite from ticks carrying B. burgdorferi, is a major threat to human health in many areas of the United States. Previous studies show that the prevalence of B. burgdorferi in ticks can be dramatically reduced by vaccinating rodent reservoirs with outer surface protein A from B. burgdorferi. Development of an affordable oral vaccine would enable large scale vaccination of animal reservoirs, and decrease the risk of transmitting Lyme disease to humans.