PROJECT SUMMARY / ABSTRACT Despite 20 years of research, there are no approved Alzheimer’s disease (AD) vaccines to date and the results of recent phase III clinical trials have been disappointing. A key difference between developing infectious disease vaccines and vaccines for AD is that Aβ/tau are self-antigens. The failure to respond to self-antigens is a hallmark of the immune system. To subvert this tolerance, Aβ/tau epitopes are conjugated to bacterial/viral proteins and mixed with adjuvants to induce robust antibody titers. Data from clinical studies indicate that proinflammatory immune responses can aggravate pre-existing neuroinflammation in AD and lead to serious side effects like encephalomyelitis. Also, most AD cases (~95%) are diagnosed in the elderly (>65 years). Studies show that in contrast to younger adults, adjuvant-related inflammation obstructs immune responses in older adults and that this effect can be mitigated by delivering anti-inflammatory therapies. An analysis of the current AD vaccine literature strongly supports the idea that vaccines that drive robust anti-inflammatory antibody responses are attractive for AD treatment. In the parent grant, we are testing the toxicity and safety of amyloid-like peptide nanofiber (PNF) vaccines which are known to be self-adjuvanting and anti-inflammatory using yeast models. We are also assessing their efficacy in aged mice against influenza infection. Within this scope, here, we propose to develop nanovaccines targeting Aβ and tau using PNFs to combat AD. We hypothesize that (i) PNFs are not neurotoxic and do not seed the formation of toxic oligomeric species and that (ii) PNFs bearing Ab/tau epitopes will elicit robust titers of functional antibodies in mice. In aim 1, we will synthesize and characterize PNFs bearing relevant Aβ/tau epitopes and use established cell culture models to assess that conjugation of Aβ/tau does not impart toxicity. We will use biosensor cells to test the capacity of the constructs to seed amyloid aggregation and complement these studies using Thioflavin T assays and electron microscopy. We will also confirm the lack of Aβ and tau pathology of the vaccine constructs in primary neurons. In aim 2, mice will be immunized with nanofiber vaccines bearing Ab/tau epitopes currently used in clinical trials and the magnitude and persistence of the antibody response will be assessed and affinities of Abs in the serum to monomeric and oligomeric forms of Ab/tau will be analyzed along with their ability to prevent aggregation of amyloids. The synthetic nature of the constructs allows for high purity, minimal contamination, and biochemical and biophysical validation representing a significant advantage over current adjuvants which are heterogeneous mixtures of plant- or animal-derived byproducts. Due to the modular nature of fibril assembly, peptides linked to different antigens or conformers of Ab/tau can be mixed to improve the breadth of protection. Completion of th...