Cerebrospinal fluid amyloid β peptide patterns in Alzheimer's disease patients and nondemented controls depend on sample pretreatment:: Indication of carrier-mediated epitope masking of amyloid β peptides
Cerebrospinal fluid amyloid β peptide patterns in Alzheimer's disease patients and nondemented controls depend on sample pretreatment:: Indication of carrier-mediated epitope masking of amyloid β peptides
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DOI：
10.1002/elps.200305992
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发表时间：
2004-09-01
期刊：
影响因子：
2.9
通讯作者：
Wiltfang, J
中科院分区：
文献类型：
--
作者：
Bibl, M;Esselmann, H;Wiltfang, J
基于尿素的淀粉样蛋白 β (Abeta)-十二烷基硫酸钠-聚丙烯酰胺凝胶电泳与蛋白质免疫印迹 (Abeta-SDS-PAGE/免疫印迹) 的定量分析揭示了阿尔茨海默病 (AD) 患者和非痴呆对照中高度保守且疾病特异性的 Abeta 肽模式 (Abeta 1-37,1-38,1-39,1-40,1-42)。为了进一步标准化该方法，我们使用不同的 Abeta-SDS-PAGE/免疫印迹和 Abeta1-42 酶联免疫吸附测定 (ELISA) 分析前程序分析了 8 名可能的 AD 患者和 7 名非痴呆对照者的脑脊液 (CSF)。两个诊断组均通过 Abeta1-42 的绝对水平和 Abeta1-42/40、1-42/38、1-42/39 的比率进行显着区分。脑脊液的分析前冷冻导致所有 AD 肽种类的显着损失。这种效应对于 Abeta1-42 最为明显，并且可以通过冷冻前的 SDS 热变性来完全阻止。 SDS 热变性 CSF 的长期储存会导致 Abeta1-42 的选择性丢失，并损害通过 Abeta-SDS-PAGE/免疫印迹测量的诊断组的辨别力。冷冻和储存均不会显着影响 Abeta1-42-ELISA 测定的绝对 Abeta1-42 水平，但都会损害诊断组的区分。因此，我们建议立即分析 Abeta1-42-ELISA 样品，在短暂冷冻间隔后进行 Abeta-SDS-PAGE/免疫印迹分析，并避免延长储存间隔。值得注意的是，Abeta-SDS-PAGE/免疫印迹检测到的 CSF 中 Abeta1-42 水平比 Abeta1-42-ELISA 高出三倍。总之，我们的结果表明 Abeta1-42 的载体介导的表位掩蔽。
A quantitative urea-based amyloid beta (Abeta)-sodium dodecyl sulfate-polyacrylamide gel electrophoresis with Western immunoblot (Abeta-SDS-PAGE/immunoblot) reveals highly conserved and disease-specific Abeta peptide patterns (Abeta 1-37,1-38,1-39,1-40,1-42) in Alzheimer's disease (AD) patients and nondemented controls. For further standardization of this method, we analyzed cerebrospinal fluid (CSF) of eight probable AD patients and seven nondemented controls using different preanalytical procedures for Abeta-SDS-PAGE/immunoblot and Abeta1-42-enzyme linked immunosorbent assay (ELISA). Both diagnostic groups were discriminated significantly by absolute levels of Abeta1-42 and ratios of Abeta1-42/40, 1-42/38, 1-42/39. Preanalytical freezing of CSF led to a highly significant loss of all AD peptide species. This effect was most pronounced for Abeta1-42 and completely prevented by SDS-heat denaturation prior to freezing. Prolonged storage of SDS-heat denatured CSF led to a selective loss of Abeta1-42 and impaired the discrimination of diagnostic groups as measured by Abeta-SDS-PAGE/immunoblot. Neither freezing nor storage significantly affected absolute Abeta1-42 levels as determined by Abeta1-42-ELISA, but both impaired the discrimation of diagnostic groups. Hence, we suggest immediate analysis of samples for Abeta1-42-ELISA, analysis after a short freezing interval for Abeta-SDS-PAGE/immunoblot, and avoidance of prolonged storage intervals. Remarkably, Abeta-SDS-PAGE/immunoblot measured threefold higher levels of Abeta1-42 in CSF than Abeta1-42-ELISA. In summary, our results indicate carrier-mediated epitope masking of Abeta1-42.