Alzheimer患者血清中含有低水平及低亲和力的抗Aβ自身抗体

Reduced low-affinity anti-β-amyloid autoantibodies in serum from Alzheimer's disease

目的研究AD病人血清中Aβ自身抗体的特性及对老年斑的亲和力。方法选择AD、血管性痴呆(vascular dementia,VD)患者及正常老年人做为研究对象,采集血清标本,测定抗体含量,并亲和纯化抗体进行免疫组化染色。结果 AD患者血清中含有低水平的Aβ自身抗体,但抗体含量与性别、年龄和MMSE评分没有相关性;AD体内的抗体不能识别Tg2576鼠脑内的老年斑。结论 Aβ自身抗体的降低是AD病人特有的免疫低反应性所致;Aβ自身抗体与老年斑的亲和力明显降低;这些抗体的病理生理作用需要进一步研究。

Objective To investigate the characterization of anti-Aβ autoantibodies in AD patients and affinity ability of autoantibodies stainning the Aβplaques in vitro. Methods ELISA was performed to detect levels of naturally occuring anti-Aβautoantibodies in surum from AD patients, vascular dementia and age-macthed healthy controls.Immunohistochemistry assay was employed to confirm the affinity abillity of anti-Aβautoantibodies stainning the Aβ plaques in vitro. Results Naturally occuring anti-Aβautoantibodies in surum from AD patients was significantly lower than those from vascular dementia and healthy controls. The autiantibodies levels were independent of gender,age and MMSE scores in AD patients. Autoantibodies purified from healthy individuals and vascular dementia patients could readily stain the Aβplaques in transgenic mouse Tg2576, while those from AD patients could not. Conclusion Compared with vascular dementia and healthy controls, AD patients have obviously lower anti-Aβautoantibodies which could not stain Aβplaques in transgenic mouse and showed a low-affinity ability with Aβplaques in vitro. The petential pathophysiological function of autoantibodies in AD patients needs futher study.