VACCINE DEVELOPMENT FOR ALPHAVIRUSES

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 基孔肯雅病是由致病性甲型病毒基孔肯雅病毒引起的一种媒介传播的病毒性疾病。最初，我们在一个实验性的非人类灵长类动物模型(束支原体)(n=3)中重述了这种病毒疾病。这一发病率模型模拟了临床综合征，并显示了人类感染中注意到的自然疾病的特征。该模型的建立是为了提供一个先进的监测系统，用于测试针对CHIK开发的候选疫苗的效力。正在开发的Chik疫苗基于含有微小核糖体病毒内部核糖体进入位点(IRES)的构建物，以取代Chik病毒(CHIKV)结构蛋白的亚基因组启动子。这种方法可以高度减弱病毒，防止蚊子感染，但保留了免疫原性。CHIK非人灵长类动物模型被用来在不同的实验中测试两种版本的疫苗(CHIK/IRESv1，v2)。在动物体内植入远程无线电遥测仪，持续监测临床体征(核心体温、呼吸频率、心率、心电图)，并在接种疫苗后和攻击后采集样本进行病毒血症、抗体和病毒血症检测。每组(N=16只)，皮下(SQ；Chik/IRESv1)或皮下(ID；Chik/IRESv2)皮下接种5.5^log单剂疫苗，或假接种生理盐水。免疫后约45天，所有动物用6.0log野生型CHIKV攻击SQ。中和抗体效价以CHIK/IRESv2疫苗组最高，CHIK/IRESv1(ID)组和CHIK/IRESv1(SQ)组稍低。接种后很少或没有观察到病毒，通过植入式遥测测量的接种后的临床反应并不显著。在挑战WT CHIKV时，接种疫苗的动物在感染后45天内没有出现病毒血症、核心体温升高或任何其他指示Chik病的临床特征。相比之下，接种假疫苗的对照组出现了严重的病毒血症(+1-3d PI)，并显示出核心体温、心率和心电图测量的显著变化。CHIK/IRES候选疫苗是安全的，具有高度的免疫原性，并保护非人类灵长类动物免受使用WT CHIKV的强大实验挑战模型的影响。可以探索疫苗剂量和接种途径的改进，以评估与该疫苗产品相关的长期免疫力。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Chikungunya (CHIK) is a vectorborne viral disease caused by chikungunya virus, a pathogenic alphavirus. Initially we recapitulated the viral disease in an experimental nonhuman primate model (M. fascicularis) (n=3). This morbidity model emulated the clinical syndrome and showed the hallmarks of natural disease noted in human infections. The model was established to provide an advanced monitoring system for testing the efficacy of candidate vaccines developed against CHIK. The CHIK vaccines under development are based upon constructs containing a picornavirus internal ribosomal entry site (IRES) to replace the subgenomic promoter for expression of the CHIK virus (CHIKV) structural proteins. This approach highly attenuates the virus and prevents mosquito infection, but preserves immunogenicity. The CHIK nonhuman primate model was used to test two versions of the vaccine (CHIK/IRESv1, v2) in separate experiments. Animals were implanted with remote radiotelemetry for continuous monitoring of clinical signs (core temperature, respiratory rate, heart rate, ECG) and samples were taken for viremia, antibody, and viremia assays following vaccination and after challenge. Groups of four animals (N=16) prime vaccinated with a single dose of 5.5^log by either the subcutaneous (SQ; CHIK/IRESv1) or intradermal (ID; CHIK/IRESv2) route, or sham vaccinated with saline. Approximately 45 days postvaccination, all animals were challenged SQ with 6.0log of wild-type CHIKV. The highest neutralizing antibody titers were generated by the CHIK/IRESv2 vaccine group, with slightly lower mean titers by CHIK/IRESv1 (ID) and CHIK/IRESv1 (SQ) groups. Little or no virema was noted after vaccination, and clinical response after vaccination as measured by implantable telemetry was unremarkable. Upon challenge with WT CHIKV, no vaccinated animals developed viremia, elevation in core temperature, or any other clinical hallmarks indicative of CHIK disease up to +45 days postinfection. In contrast, sham-vaccinated controls developed viremia acutely (+1-3d PI) and showed dramatic changes in core temperature, heart rate, and electrocardiogram measurements. The CHIK/IRES vaccine candidates are safe, highly immunogenic, and protect nonhuman primates from a robust experimental challenge model using WT CHIKV. Refinements in vaccine dose, as well as route of vaccination may be explored to evaluate the long term immunity associated with this vaccine product.