Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK.
Scottish Biologics Facility, University of Aberdeen, Aberdeen, UK.
Alzheimers Res Ther. 2024 Oct 2;16(1):209. doi: 10.1186/s13195-024-01561-1.
Recent advances in blood-based biomarker discovery are paving the way for simpler, more accessible diagnostic tools that can detect early signs of Alzheimer's disease (AD). Recent successes in the development of amyloid-targeting immunotherapy approaches mark an important advancement in providing new options for the treatment of AD. We have developed a set of high-affinity monoclonal antibodies (mAbs) to tau protein that have the potential as tools for diagnosis and treatment of AD.
Sheep were immunised with either full-length tau (1-441) or truncated paired helical filament (PHF)-core tau (297-391). A stringent bio-panning and epitope selection strategy, with a particular focus directed to epitopes within the disease-relevant PHF-core tau, was used to identify single-chain antibodies (scAbs). These scAbs were ranked by affinity for each epitope class, with leads converted to high-affinity mAbs. These antibodies and their potential utility were assessed by their performance in tau immunoassays, as well as their ability to prevent tau aggregation and propagation. Further characterisation of these antibodies was performed by immunohistochemical staining of brain sections and immuno-gold electronmicroscopy of isolated PHFs.
Our work resulted in a set of high-affinity antibodies reacting with multiple epitopes spanning the entire tau protein molecule. The tau antibodies directed against the core tau unit of the PHF inhibited pathological aggregation and seeding using several biochemical and cell assay systems. Through staining of brain sections and PHFs, the panel of antibodies revealed which tau epitopes were available, truncated, or occluded. In addition, highly sensitive immunoassays were developed with the ability to distinguish between and quantify various tau fragments.
This article introduces an alternative immunodiagnostic approach based on the concept of a "tauosome" - the diverse set of tau fragments present within biological fluids. The development of an antibody panel that can distinguish a range of different tau fragments provides the basis for a novel approach to potential diagnosis and monitoring of disease progression. Our results further support the notion that tau immunotherapy targeting the PHF-core needs to combine appropriate selection of both the target epitope and antibody affinity to optimise therapeutic potential.
血液生物标志物发现方面的最新进展为更简单、更易获得的诊断工具铺平了道路，这些工具可以检测到阿尔茨海默病（AD）的早期迹象。淀粉样蛋白靶向免疫疗法的最新成功标志着为 AD 治疗提供新选择的重要进展。我们开发了一组针对 tau 蛋白的高亲和力单克隆抗体（mAbs），它们有可能成为 AD 诊断和治疗的工具。
绵羊用全长 tau（1-441）或截断的配对螺旋丝（PHF）-核心 tau（297-391）免疫。采用严格的生物淘选和表位选择策略，特别针对与疾病相关的 PHF 核心 tau 内的表位，鉴定单链抗体（scAbs）。根据每种表位类别的亲和力对这些 scAbs 进行排名，将领先的 scAbs 转化为高亲和力的 mAbs。通过 tau 免疫测定评估这些抗体及其潜在用途，以及它们预防 tau 聚集和传播的能力。通过对脑切片进行免疫组织化学染色和对分离的 PHFs 进行免疫金电子显微镜检查，进一步对这些抗体进行了表征。
我们的工作产生了一组针对横跨整个 tau 蛋白分子的多个表位的高亲和力抗体。针对 PHF 核心 tau 单位的 tau 抗体通过几种生化和细胞测定系统抑制病理性聚集和接种。通过对脑切片和 PHFs 的染色，抗体组揭示了哪些 tau 表位可用、截断或被封闭。此外，开发了具有区分和定量各种 tau 片段能力的高灵敏度免疫测定法。
本文介绍了一种基于“tauosome”概念的替代免疫诊断方法-存在于生物体液中的不同 tau 片段集。开发能够区分一系列不同 tau 片段的抗体组为潜在诊断和监测疾病进展提供了一种新方法的基础。我们的结果进一步支持了这样一种观点，即针对 PHF 核心的 tau 免疫疗法需要结合对靶表位和抗体亲和力的适当选择，以优化治疗潜力。
