Immunogenicity & efficacy of chimeric flu virus expressing Ab42 B cell epitope

描述（由申请人提供）：我们和其他人已经证明了β -淀粉样蛋白（AB）肽抗体的诱导在临床前和临床环境中对阿尔茨海默病具有治疗作用。这种方法目前受到引发病理性自身反应性的阻碍。为了克服这个问题，我们开发了几种策略来限制病理免疫。例如，我们制作了一种表位疫苗，由AB42的小免疫优势自身B细胞肽与外源CD4+Th细胞表位融合组成，并证明这种疫苗可诱导高滴度的抗AB抗体，而不会产生针对AB的潜在有害的自身反应性T细胞。重要的是，这些抗体具有治疗活性，正如我们在两种不同的AD小鼠模型（APP/Tg 2576和3xTg-AD）中所显示的那样。在证明了在没有病理性自身反应的情况下选择性诱导对AB有益的抗体反应的可行性后，我们决定将这些研究扩展到更临床适用的系统。我们与合作研究者合作，利用流感病毒平台将AB42的免疫显性B细胞表位（AB1-10）传递到宿主体内。在我们的初步数据中，我们已经产生了一种流感ab1 -10疫苗，该疫苗可诱导强大的抗ab和抗流感抗体，并减少免疫3xTg-AD小鼠大脑中的ab沉积。因此，在本提案的前三个转化目的中，我们计划了解(i)重组流感- AB1-10疫苗在无ad样病理（Aim 1）以及早期（Aim 2）和晚期（Aim 3） ad样病理的3xTg-AD小鼠中的免疫原性和有效性。本研究的最后一个目的是探索该疫苗产生抗ab抗体的免疫学机制，并确定参与该过程的抗病毒记忆Th细胞的特异性。因此，在本研究结束时，我们将了解控制AB1-10和流感特异性抗体产生的细胞和分子机制。这项提议的长期目标是研制出安全有效的双重（流感- ab）疫苗，这种疫苗可能会在出现症状前预防阿尔茨海默病的发展，同时保护他们免受流感感染。公共卫生相关性：阿尔茨海默病是美国痴呆症的主要病因，其特点是发病隐匿，认知能力逐渐下降，影响记忆、语言、判断、对时间和地点的定位等。病理表现为淀粉样斑块、神经原纤维缠结、神经突营养不良和神经元的普遍丧失。研究表明，β -淀粉样蛋白肽抗体的诱导在临床前和临床环境中对阿尔茨海默病具有治疗作用。这种方法目前受到病理性自身反应性T辅助细胞的激发的阻碍。为了克服这个问题，我们和其他人正在开发几种策略来限制病理性免疫。在目前的项目中，我们建议基于流感病毒载体和来自β -淀粉样蛋白肽的免疫优势B细胞表位产生安全有效的双重疫苗，这可能会预防/减少被诊断为早期AD的症状前患者阿尔茨海默病病理的发展，同时保护他们免受流感感染。

DESCRIPTION (provided by applicant): We and others have demonstrated that induction of antibodies to the beta-amyloid (AB) peptide endows therapeutic effects in Alzheimer's disease both in pre-clinical and clinical settings. This approach is currently hampered by elicitation of pathological autoreactivity. In order to overcome this problem we have developed several strategies to limit pathological immunity. For example, we generated an epitope vaccine composed of small immunodominant self B cell peptide of AB42 fused with a foreign CD4+Th cell epitope and demonstrated that such vaccine induced high titers of anti-AB antibodies without generation of potentially harmful autoreactive T cells specific to AB. Importantly, these antibodies were therapeutically active, as we showed in two different mouse models of AD (APP/Tg 2576 & 3xTg-AD). After having demonstrated feasibility of selectively inducing a beneficial antibody response to AB in absence of pathological autoreactivity, we decided to expand these studies to a more clinically applicable system. In collaboration with our co-investigator, we have used the influenza virus platform for delivery of immunodominant B cell epitopes of AB42 (AB1-10) into the host. In our preliminary data we have generated a flu-AB1-10 vaccine that induces robust anti-AB and anti-influenza antibodies and reduces AB-deposits in the brains of immune 3xTg-AD mice. Thus, in the first three translational Aims of this proposal we plan to learn about (i) immunogenicity and efficacy of recombinant flu- AB1-10 vaccine in 3xTg-AD mice without AD-like pathology (Aim 1), as well as with early (Aim 2) and late (Aim 3) AD-like pathology. The last Aim 4 of this study is designed to explore immunological mechanism/s of generation of anti-AB antibodies by this vaccine and identify specificity of anti-viral memory Th cells involved in this process. Thus, at the end of this study we will learn about cellular and molecular mechanisms governing the generation of antibodies specific to both AB1-10 and influenza. The long-term goal of this proposal will be a generation of the safe and effective dual (flu-AB) vaccine that may prevent development of AD pathology in pre-symptomatic people, protecting them from the flu infection at the same time. PUBLIC HEALTH RELEVANCE: Alzheimer's Disease is the major cause of dementia in the US and is characterized by an insidious onset and progressive cognitive decline that impacts memory, language, judgment, orientation to time and place, etc. Pathologically there is an increase in the presence in amyloid plaques, neurofibrillary tangles, dystrophic neurites and a general loss of neurons. It was demonstrated that induction of antibodies to the beta-amyloid peptide endows therapeutic effects in Alzheimer's disease both in pre-clinical and clinical settings. This approach is currently hampered by elicitation of pathological autoreactive T helper cells. In order to overcome this problem we and others are developing several strategies to limit pathological immunity. In current project we are proposing to generate the safe and effective dual vaccine, based on influenza viral vector and immunodominant B cell epitope from beta-amyloid peptide that may prevent/reduce development of Alzheimer's disease pathology in pre-symptomatic people diagnosed with early-stage AD, protecting them from the flu infection at the same time.