天然Aβ寡聚体抗体的制备研究

Purification of Aβ oligomers antibodies from IVIG

摘要:

阿尔茨海默症(Alzheimer，s disease, AD) 主要是由β-淀粉样蛋白单体分子(β-amyloid, Aβ)聚集而引起的以老年人记忆力下降和脑部形成老年斑、神经元内形成神经缠绕为特征的神经退行性疾病。研究表明，Aβ寡聚体是AD发生发展的主要因素。在本研究中，我们首先制备了Aβ寡聚体和交联该寡聚体的亲和层析填料，然后应用亲和层析技术从IVIG中纯化获得了结合Aβ寡聚体的多克隆抗体（antibodies against Aβ oligomer，Ab-Aβo），并应用ELISA和Western blot 对其进行了鉴定，以MTT实验分析了该抗体对Aβ42诱导的细胞毒性作用的影响。结果表明，纯化获得的Ab-Aβo能特异性地结合体外合成或细胞形成的Aβ 寡聚体，并且与Aβ寡聚体的结合活性比IVIG高1000倍，同时该寡聚体抗体能够显著抑制Aβ42诱导的细胞毒性。我们的研究为应用天然寡聚体抗体对AD的免疫治疗奠定了基础。

Abstract:

Alzheimer’s disease (AD) is a neurodegenerative disease mainly caused by the accumulation of β-amyloid (Aβ) monomer molecules, leading to the formation of senile plaque, intracellular neurofibrillary tangles, and memory loss in the elderly. Recent evidences suggest that oligomeric Aβ species are a major risk factor in the progress of AD. In this study, we prepared Aβ oligomer and cross-linked Aβ oligomer to beaded-polyacrylamide resin. Aβ oligomer specific polyclonal antibodies (Ab-Aβo) were isolated from IVIG by Aβ oligomer affinity chromatography and their characteristics were identified by ELISA and Western blot assay. The effect of Ab-Aβo on cytotoxicity was further analyzed by MTT assay. The results showed that purified Ab-Aβo specifically recognized both synthesized and cell-produced Aβ oligomers. Compared with IVIG, the binding activity of the antibodies to Aβ oligomers was increased by 1000 times and Ab-Aβo significantly attenuated Aβ42-induced cytotoxicity in SH-SY5Y neuroblastoma cells, suggesting that Ab-Aβo may be a potential immunotherapeutic for the treatment of AD.