Rift Valley Fever Virus MP-12 Vaccine Completion

描述（由申请方提供）：裂谷热（RVF）是撒哈拉以南非洲的一种病毒性地方病，是埃及最近几次动物流行病和流行病的原因。它是一种蚊媒包膜RNA病毒，也通过气溶胶途径传染。在2-6天的潜伏期后，它通常会引起急性发热性疾病，其中约10%的人发展为视网膜炎，1%失明，约1%发展为暴发性病程，死亡率高达50%。 裂谷热病毒是一种A级高优先生物恐怖剂。 它有可能扩大并通过美国发现的许多蚊子物种传播。先前的人类疫苗接种工作包括IND福尔马林灭活疫苗。它产生了中和抗体，但它需要一个三针的初级系列和重复的助推器。为了增强免疫原性，USAMRIID创建了一种名为MP 12的活疫苗，在5-氟尿嘧啶存在下通过连续传代进行诱变和减毒，随后进行空斑克隆和扩增。大约60名志愿者在1980年代初准备的IND下接受了免疫接种。结果是有希望的，因为在一次注射后形成了保护性抗体，并且这些抗体在一年后仍然存在。观察到最小的副作用。 这种疫苗后来被认为是获得许可的裂谷热疫苗的主要候选疫苗。 本项目将继续该疫苗的开发，通过DNA测序将减毒疫苗与亲本疫苗进行比较，以精确识别突变点，并为在DNA序列水平上定量确定减毒病毒的遗传稳定性提供依据。将对几名在本IND下接种疫苗的志愿者进行接种，我们将通过DNA序列分析再次检查回收的病毒是否有任何回复突变的迹象。我们将确定优化宿主细胞系的生长条件，建立主细胞库和用于进一步生产的病毒种子批，并编写新的IND以支持疫苗的最终II期和III期临床试验。

DESCRIPTION (provided by applicant): Rift Valley Fever (RVF) is a viral disease endemic to sub-Saharan Africa and has been the cause of several recent epizootics and epidemics in Egypt. It is a mosquito-borne enveloped RNA virus, also infectious via the aerosol route. Following a 2-6 day incubation, it typically causes acute febrile illness, and about 10% of those develop retinitis, 1% blindness, and about 1% develop a fulminant course with up to 50% mortality. RVF virus is a class A high priority bioterrorism agent. It has the potential to amplify and be transmitted by many mosquito species found in the United States. Prior vaccination efforts in humans have included an IND formalin inactivated vaccine. It produced neutralizing antibodies but it required a three-shot primary series and repeated boosters. To enhance immunogenicity, USAMRIID created a live vaccine designated MP12, which was mutagenized and attenuated by serial passage in the presence of 5-fluorouracil with subsequent plaque cloning and amplification. Approximately 60 volunteers were immunized under an IND prepared in the early 1980's. Results were promising in that protective antibodies were formed following one injection, and these remained after one year. Minimal side effects were observed. This vaccine has since been considered a prime candidate for a licensed RVF vaccine. This project will continue this vaccine development by comparing the attenuated vaccine with the parent using DNA sequencing to precisely identify the mutation points and provide a basis to quantitatively determine the genetic stability of the attenuated virus at the DNA sequence level. Several volunteers vaccinated under the present IND will be inoculated, and we will examine recovered virus for any signs of reversion again by DNA sequence analysis. We will determine the growth conditions in an optimized host cell line, establish a master cell bank and viral seed lot to be used for further production, and write a new IND to support final phase II and III clinical testing of the vaccine.