Active immunization with bacteriophage AP205 VLPs results in reduced amyloid load and microgliosis in 5xFAD female mice

Pilipenko, VladimirsLieknina, IlvaSkrastina, DaceAktas, SelenRevina, Beatrise LuizeUpite, JolantaJansone, Baiba2026-04-042026-04-0420260028-12981432-1912https://doi.org/10.1007/s00210-025-04739-yhttps://hdl.handle.net/11616/109915Alzheimer's disease (AD) is the leading cause of dementia worldwide and the accumulation of amyloid beta (A beta) oligomers in the brain parenchyma is one of the main characteristics of AD. Pyroglutamate-modified amyloid beta (pE3A beta) forms are highly pathogenic components of A beta plaques and are viable targets for disease-modifying strategies. Active immunization using virus-like particles (VLPs) represents a promising therapeutic approach to combating AD. Using RNA bacteriophage-based VLPs, we developed and tested a vaccine targeting pE3A beta in 5xFAD female mice. This study utilized the bacteriophage AP205 VLP platform to generate candidate compounds for active immunization. AP205 VLPs were modified to display short pE3A beta peptides. At 2 months of age, 5xFAD female mice received four immunizations with either pE3A beta VLPs or AP205 VLPs. Blood titers were assessed biweekly for the first 45 days and then every 2 months using ELISA. Behavioral tests, including open field, spontaneous alternation, Morris water maze, and elevated zero maze (EZM), were performed at 6 and 8 months of age. Immunohistochemical analyses evaluated levels of A beta 42, pE3A beta, glial fibrillary acidic protein (GFAP), and ionized calcium-binding adapter molecule-1 (Iba-1). pE3A beta VLPs and AP205 VLPs did not alter cognitive or locomotor performance in 5xFAD mice. The working memory of 8-month-old pE3A beta VLP-treated mice was better than it was at 6-months of age. A moderate reduction in A beta 42 pathology and microglial activation was observed in both vaccinated groups. VLP-based vaccine administration showed no behavioral improvements in 5xFAD mice but demonstrated modest effects on A beta 42 load and microgliosis.eninfo:eu-repo/semantics/openAccessPreclinical Alzheimer's diseaseAlzheimer's vaccineAnimal behavioral testingVirus-like particlesTransgenic miceActive immunization with bacteriophage AP205 VLPs results in reduced amyloid load and microgliosis in 5xFAD female miceArticle3993456945874112890210.1007/s00210-025-04739-y2-s2.0-105019534180Q2WOS:001598762300001Q20000-0002-7098-7483