Cauet Gilles, Daynès Aurélien, Temurok Nevzat
HORIBA ABX SAS, Parc Euromédecine - Rue du Caducée, BP 7290, 34184 Montpellier Cedex 4, France.
Pract Lab Med. 2016 Feb 19;4:82-88. doi: 10.1016/j.plabm.2016.02.003. eCollection 2016 Apr 1.
The technology of magnetic field-assisted immuno-agglutination of superparamagnetic particles allows sensitive detection of biomarkers in whole blood. However, we observed non-specific agglutination (NSA), due to interfering plasma proteins, that negatively affects C-reactive protein immunoassay. The objective of the study was to identify the plasma proteins involved and to eliminate these interferences.
Plasma was fractionated by size exclusion HPLC and each fraction was tested for non-specific agglutination. In addition, plasma proteins bound to magnetic particles were analyzed by SDS-gel electrophoresis and identified by mass spectrometry.
We found that NSA was due to the binding of some lipoproteins to the particles. NSA was observed in the presence of purified LDL and VLDL but not HDL. NSA was mediated by the binding of ApoB100 to magnetic particles through its heparin binding sites. These interferences could be eliminated by addition of heparin or other polyanions like dextran sulfate to the assay buffer.
NSA results from the binding of some plasma lipoproteins to magnetic particles. The use of a polyanion to eliminate these interferences allows the formulation of a stable reagent.
超顺磁性颗粒的磁场辅助免疫凝集技术能够灵敏检测全血中的生物标志物。然而，我们观察到由于干扰性血浆蛋白导致的非特异性凝集（NSA），这对C反应蛋白免疫测定产生了负面影响。本研究的目的是确定参与其中的血浆蛋白并消除这些干扰。
通过尺寸排阻高效液相色谱法对血浆进行分级分离，然后对每个级分进行非特异性凝集检测。此外，通过SDS凝胶电泳分析与磁性颗粒结合的血浆蛋白，并通过质谱进行鉴定。
我们发现NSA是由于某些脂蛋白与颗粒的结合所致。在纯化的低密度脂蛋白（LDL）和极低密度脂蛋白（VLDL）存在的情况下观察到NSA，但高密度脂蛋白（HDL）不存在时未观察到。NSA是由载脂蛋白B100（ApoB100）通过其肝素结合位点与磁性颗粒的结合介导的。通过向测定缓冲液中添加肝素或其他聚阴离子如硫酸葡聚糖可以消除这些干扰。
NSA是由某些血浆脂蛋白与磁性颗粒的结合引起的。使用聚阴离子消除这些干扰可以配制出稳定的试剂。
