Rational Development of Candidate Attenuated Flavivirus Vaccines

候选黄病毒减毒疫苗的合理开发

基本信息

批准号：
9058481
负责人：
Tian Wang
金额：
$ 61.78万
依托单位：
UNIVERSITY OF TEXAS MED BR GALVESTON
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-06-01 至 2018-10-15
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The flaviviruses contain many pathogens of public health importance, including dengue virus (DENV) and West Nile virus (WNV) for which we have no licensed vaccines. Live attenuated vaccines, which induce durable protective immunity, are one of the important strategies to control flavivirus diseases and have been very successful at controlling yellow fever (YF) and Japanese encephalitis (JE). The nonstructural (NS) proteins are associated with evasion of host innate immunity. Among them, NS4B protein has extensive homology between flaviviruses and the N-terminal region has been shown to encode a major interferon (IFN) antagonism function. Thus, we focus on NS4B to identify stable mutations that can be used to rationally attenuate candidate live flavivirus vaccines. We are using WNV as a model and have identified two highly attenuated WNV NS4B mutants. The C102S mutant has a substitution in the flavivirus conserved central hydrophobic domain of NS4B protein, which is known to contribute to the virulence phenotype of flaviviruses, and contains mutations in the attenuated derivatives of YFV, JEV and DENV. Although the NS4B-C102S mutant was highly attenuated for mouse neuroinvasiveness and neurovirulence, and conferred protective immunity in mice, it was prone to reversion. It is not an ideal candidate vaccine by itself. Another attenuated WNV mutant has a substitution in the highly conserved P38 residue in the N-terminal region of the NS4B protein. It is highly attenuated for mouse neuroinvasiveness, highly immunogenic, reversion of the mutant has not been identified. Our recent published work showed that the NS4B-P38G mutant induced higher innate cytokine and memory T cell responses in mice than the wild-type (WT) NY99 strain, and immunized mice were all protected from WT WNV challenge. The underlying immune mechanisms are not clearly understood. We hypothesize that the P38G substitution in the IFN antagonism region or in combination with mutation(s) in the conserved central hydrophobic region of WNV NS4B protein will confer an attenuated phenotype and the ability to induce higher protective immunity than WT NY99, and this may serve as an excellent model to develop potential live flavivirus vaccine candidate(s). We will first elucidate the immune mechanisms by which WNV NS4B-P38G mutant triggers higher protective immunity than WT NY99. We will next determine whether incorporating the NS4B-C102S mutation will further enhance and stabilize the attenuated phenotype of WNV NS4B-P38G mutant. Lastly, we will characterize immune responses to WNV NS4B-P38G/C102S double mutant infection in mouse and human cells and evaluate the protective effects of WNV NS4B mutant strains after immunization of mice followed by lethal WT WNV challenge. Characterization of stable mutations in the highly conserved coding regions of WNV NS4B protein and investigation the mechanism by which WNV NS4B mutant induces higher protective immunity can be utilized as a paradigm to aid in the rational development of other efficacious live attenuated flavivirus vaccines.

描述（由申请人提供）：黄病毒包含许多公共健康重要性的病原体，包括登革热病毒（DENV）和西尼罗河病毒（WNV），我们没有许可的疫苗。诱导持久保护性免疫力的活疫苗是控制黄素疾病的重要策略之一，并且在控制黄热病（YF）和日本脑炎（JE）方面非常成功。非结构（NS）蛋白与逃避宿主先天免疫有关。其中，NS4B蛋白在黄病毒之间具有广泛的同源性，N末端区域已被证明可以编码主要的干扰素（IFN）拮抗功能。因此，我们专注于NS4B，以识别可用于合理减弱候选活黄病毒疫苗的稳定突变。我们使用WNV作为模型，并确定了两个高度衰减的WNV NS4B突变体。 C102S突变体在黄病毒保守的NS4B蛋白的中央疏水结构域中取代，该蛋白已知有助于黄酮病毒的毒力表型，并包含YFV，JEV和DENV的减弱衍生物中的突变。尽管NS4B-C102S突变体高度减弱了小鼠神经侵袭性和神经电动性，并在小鼠中赋予了保护性免疫，但它容易恢复。它本身不是理想的候选疫苗。另一个减弱的WNV突变体在NS4B蛋白的N末端区域的高度保守p38残基中取代。尚未鉴定出高度减弱的小鼠神经侵袭性，高度免疫原性，反复反转。我们最近发表的工作表明，与野生型NY99菌株相比，NS4B-P38G突变体在小鼠中诱导了更高的先天细胞因子和记忆T细胞反应，并且免疫小鼠均受到WT WNV挑战的保护。基本的免疫机制尚不清楚。 We hypothesize that the P38G substitution in the IFN antagonism region or in combination with mutation(s) in the conserved central hydrophobic region of WNV NS4B protein will confer an attenuated phenotype and the ability to induce higher protective immunity than WT NY99, and this may serve as an excellent model to develop potential live flavivirus vaccine candidate(s).我们将首先阐明WNV NS4B-P38G突变体触发比WT NY99更高的保护性免疫的免疫机制。接下来，我们将确定合并NS4B-C102S突变是否会进一步增强和稳定WNV NS4B-P38G突变体的衰减表型。最后，我们将表征对小鼠和人类细胞中WNV NS4B-P38G/C102S双突变体感染的免疫反应，并评估小鼠免疫后WNV NS4B突变菌株的保护作用，然后进行致命WT WNV挑战。 WNV NS4B蛋白高度保守的编码区域中稳定突变的表征和研究WNV NS4B突变体诱导较高保护性免疫的机制可以用作范式，以帮助有助于其他有效的活体消毒黄素疫苗的合理发展。

项目成果

期刊论文数量（3）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

West Nile Virus.

西尼罗病毒。

DOI：
10.1016/j.cll.2017.01.001
发表时间：
2017
期刊：
Clinics in laboratory medicine
影响因子：
1.7
作者：
Saxena,Vandana;Bolling,BethanyG;Wang,Tian
通讯作者：
Wang,Tian

Dysregulation of Toll-Like Receptor 7 Compromises Innate and Adaptive T Cell Responses and Host Resistance to an Attenuated West Nile Virus Infection in Old Mice.

Toll 样受体 7 的失调会损害老年小鼠的先天性和适应性 T 细胞反应以及宿主对减毒西尼罗河病毒感染的抵抗力。

DOI：
10.1128/jvi.02488-15
发表时间：
2016
期刊：
Journal of virology
影响因子：
5.4
作者：
Xie,Guorui;Luo,Huanle;Pang,Lan;Peng,Bi-Hung;Winkelmann,Evandro;McGruder,Brenna;Hesse,Joseph;Whiteman,Melissa;Campbell,Gerald;Milligan,GreggN;Cong,Yingzi;Barrett,AlanD;Wang,Tian
通讯作者：
Wang,Tian

West Nile Virus Infection in the Central Nervous System.

中枢神经系统的西尼罗河病毒感染。