Shifting a Paradigm in Vaccine Safety: From Empirical to Rational Attenuation

描述(由申请人提供)：在引入减毒活腮腺炎疫苗之前，腮腺炎病毒(MUV)是无菌性脑膜炎的主要原因。由于疫苗的使用，腮腺炎发病率急剧下降，尽管最近的全球复苏突显了保持强有力的疫苗接种计划的重要性。尽管自MUV被确定为该病的病原体以来，已有75年多的时间，但对病毒嗜神经性的基础几乎一无所知，控制衰减的分子决定因素也尚未确定。这使安全疫苗的开发复杂化，正如一些获得许可的腮腺炎疫苗导致无菌性脑膜炎的事实所证明的那样。流行性腮腺炎最近在美国和欧洲重新出现，导致接种疫苗的个人爆发大规模疫情。由于目前正在研制新的MUV疫苗，这使得提高疫苗安全性的研究成为当务之急。我们的目标是开发一套经过验证的、强大的体外、体外和体内测试工具包，用于预测腮腺炎疫苗是否可安全用于人类。该工作计划对疫苗学领域具有直接和长期的重要性，这些数据将为目前正在开发的合理减毒疫苗的安全测试提供信息。提出了三个协同和顺序的目标：1.确定野生型MUV体内靶向的原代细胞、组织和器官：来源已知的重组(R)野生型病毒将用于评估与疾病相关的原代细胞、组织和神经毒力的啮齿动物模型的复制能力和趋向性。我们将通过用表达RMV的增强型绿色荧光蛋白感染恒河猴来测试MUV最初感染上呼吸道上皮细胞的模型，以回答这样一个问题：在体内，MUV复制的主要靶点是什么？2.确定高度减毒和减毒不足的MUV靶向的原代细胞是否彼此不同，以及是否与目前流行的野生型病毒不同：了解安全和不安全疫苗之间的区别和相似之处对于安全疫苗的开发和许可至关重要。来自高度减毒和弱毒株的增强型绿色荧光蛋白表达MUV将在体外、体外和体内模型中进行评估，以确定病毒复制、组织趋向性和体内传播是否与已知的人类疫苗接种安全性相关。3.利用具有不同复制能力和趋向性的非重组疫苗前体和合理减毒的rMuv，开发腮腺炎疫苗安全性的体内预测因子：将鉴定一组具有基因替换和靶向突变的疫苗前体和rMuv，旨在调节复制能力和趋向性。根据猕猴的“衰减特征”，将给猕猴接种rMuv疫苗，并对其安全性进行评估。这将回答“我们能否在体外、体外和体内建立可靠的模型来预测Muv疫苗对人类安全的可能性”的问题。

DESCRIPTION (provided by applicant): Prior to the introduction of live attenuated mumps vaccines, mumps virus (MuV) was the leading cause of aseptic meningitis. Mumps incidence declined sharply due to vaccine use, although the recent global resurgence highlights the importance of maintaining robust vaccination programs. Even though it has been over 75 years since MuV was identified as the etiological agent of the disease, virtually nothing is known about the basis of virus neurotropism and the molecular determinants governing attenuation have not been identified. This complicates the development of safe vaccines as demonstrated by the fact that some licensed mumps vaccines caused aseptic meningitis. Mumps has recently reemerged in the US and Europe causing large outbreaks in vaccinated individuals. Since new MuV vaccines are currently in the pipeline this makes research to advance vaccine safety a priority. Our goal is to develop a toolkit of validated, robust in vitro, ex vivo and in vivo assays which predict whether or not mumps vaccines are safe for use in humans. The program of work has both immediate and long term importance for the field of vaccinology and the data will inform safety testing of rationally-attenuated MuV vaccines which are currently in development. Three synergistic and sequential aims are proposed: 1. Determine the primary cells, tissues and organs targeted by wild-type MuV in vivo: Recombinant (r) wild-type viruses of known provenance will be used to assess replicative capacity and tropism in disease- relevant primary cells, tissues and a rodent model of neurovirulence. We will test the model that MuV initially infects epithelia in the upper respiratory tract by infecting rhesus macaques with an rMV-expressing enhanced green fluorescent protein to answer the question, "what are the primary target sites of MuV replication in vivo"? 2. Determine if the primary cells targeted by highly attenuated and under-attenuated MuVs differ from each other and from the currently circulating wild-type virus: Understanding differences and similarities between safe and unsafe vaccines is critical for the development and licensing of safe vaccines. Enhanced green fluorescent protein-expressing MuVs derived from highly attenuated and under-attenuated strains will be assessed in the in vitro, ex vivo and in vivo models to determine if virus replication, tissue tropism and dissemination in vivo correlate with the known safety profile in human vaccinees. 3. Develop in vivo predictors for mumps vaccine safety using non-recombinant vaccine progenitors and rationally attenuated rMuVs which have differing replicative capacity and tropism: A set of vaccine progenitors and rMuVs with gene replacements and targeted mutations designed to modulate replicative capacity and tropism will be characterized. Based on their "attenuation signature" macaques will be vaccinated with the rMuVs and the safety profile will be assessed. This will answer the question "can we develop robust in vitro, ex vivo and in vivo models which predict the likelihood that MuV vaccines will be safe in humans".