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

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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.