Department of Neurology Research, Beaumont Health System, Royal Oak, MI, United States.
Immunol Lett. 2013 Jul-Aug;154(1-2):7-11. doi: 10.1016/j.imlet.2013.07.008. Epub 2013 Aug 6.
Intravenous immunoglobulin (IVIG) products are being investigated as possible therapeutic agents for mild cognitive impairment and Alzheimer's disease (AD). Anti-Aβ antibodies have been measured by ELISA in unfractionated IVIG products and in affinity-purified antibodies from these products, but it is unclear if similar results are obtained with these two approaches. Measurements of anti-Aβ antibodies in unfractionated IVIG may be confounded by the presence of polyvalent antibodies which can bind to multiple antigens, including those on ELISA plates; whether this is an issue when measuring anti-Aβ antibodies in purified antibody eluates from IVIG is also unknown. The objective of this study was to clarify these issues. The concentrations of specific antibodies to Aβ1-42 monomer and the percentages of specific binding to it were compared via ELISA between three unfractionated IVIG products (Gamunex [Talecris], Gammagard [Baxter], and Flebogamma [Grifols]) and their affinity-purified anti-Aβ antibodies. The concentrations of anti-Aβ antibodies in unfractionated IVIG products were higher than in their respective purified anti-Aβ eluates, and the rank order of the IVIG products with respect to their anti-Aβ concentrations differed between the two types of samples. The percentages of specific binding to Aβ were lower for unfractionated IVIG than for purified anti-Aβ eluates. These findings indicate that ELISA measurements of specific anti-Aβ antibodies and percentages of specific binding to Aβ produce different results depending upon whether these measurements are made in unfractionated IVIG products or their purified anti-Aβ antibodies. Polyvalent binding occurs even with purified anti-Aβ antibodies eluated from IVIG products, but it is less extensive than with unfractionated IVIG.
静脉注射免疫球蛋白（IVIG）产品正被研究作为轻度认知障碍和阿尔茨海默病（AD）的潜在治疗药物。通过 ELISA 在未分级的 IVIG 产品和这些产品的亲和纯化抗体中测量了抗 Aβ 抗体，但尚不清楚这两种方法是否获得相似的结果。在未分级的 IVIG 中测量抗 Aβ 抗体可能会受到多价抗体的干扰，这些抗体可以结合多种抗原，包括 ELISA 板上的抗原；当测量从 IVIG 中纯化的抗体洗脱物中的抗 Aβ 抗体时，是否存在这个问题也是未知的。本研究的目的是阐明这些问题。通过 ELISA 比较了三种未分级的 IVIG 产品（Gamunex[泰莱利斯]、Gammagard[百特]和 Flebogamma[基立福]）及其亲和纯化的抗 Aβ 抗体对 Aβ1-42 单体的特异性抗体浓度和对其的特异性结合百分比。未分级的 IVIG 产品中的抗 Aβ 抗体浓度高于各自的纯化的抗 Aβ 洗脱物，并且两种类型的样品中 IVIG 产品的抗 Aβ 浓度的排序不同。未分级的 IVIG 中抗 Aβ 的特异性结合百分比低于纯化的抗 Aβ 洗脱物。这些发现表明，ELISA 测量特定的抗 Aβ 抗体和对 Aβ 的特异性结合百分比会产生不同的结果，具体取决于这些测量是在未分级的 IVIG 产品中还是在其纯化的抗 Aβ 抗体中进行。即使是从 IVIG 产品中洗脱的纯化的抗 Aβ 抗体也会发生多价结合，但与未分级的 IVIG 相比，其结合程度较小。
