Tailleux A, Torpier G, Caron B, Fruchart J C, Fievet C
SERLIA et INSERM U325, Institut Pasteur, Lille, France.
J Lipid Res. 1993 May;34(5):719-28.
In this study, we have documented immunochemical properties of apolipoprotein (apo) B-containing particles (LpB) extracted from human atherosclerotic lesions obtained during vascular reconstructive surgery of patients. These properties were compared to those of particles purified from corresponding atherosclerotic plasma and healthy control plasma. LpB immunoreactivities were tested in solid phase competitive binding radioimmunoassays using five anti-apoB monoclonal antibodies (MAb) for which epitopes have been previously located on the protein. The regions encompassed amino acids 405 to 539 (MAb B1), 1854 to 1879 (MAb B4), 3506 (MAb BA11), and 4355 (MAb BL3). The fifth antibody (MAb BL5) recognizes a conformationally expressed epitope. LpB from lesions presented a significantly decreased immunoreactivity as compared to LpB from respective plasma except for the epitope recognized by MAb BA11 located precisely in the low density lipoprotein (LDL) receptor binding site. The accessibility of the four sequential epitopes was similar on LpB from atherosclerotic and healthy plasma while it was decreased for the conformational one in LpB from atherosclerotic samples. These altered immunoreactivities were not related to changes in chemical composition of LpB as this was quite comparable in all preparations. With regard to electronegativity, apoB fragmentation, immunological accessibility, and size distribution of the particles, changes seem to increase in the following order from healthy plasma, atherosclerotic plasma, and the corresponding lesions. The results confirm some structural characteristics of oxidatively modified particles from human atherosclerotic lesions and to a lesser degree from respective plasma, but more specifically demonstrate a global conformational change in LpB from lesions, this change being perhaps initiated in the plasma.
在本研究中，我们记录了从接受血管重建手术患者的人类动脉粥样硬化病变中提取的含载脂蛋白（apo）B颗粒（LpB）的免疫化学特性。将这些特性与从相应动脉粥样硬化血浆和健康对照血浆中纯化的颗粒的特性进行了比较。使用五种抗apoB单克隆抗体（MAb）在固相竞争性结合放射免疫分析中测试了LpB免疫反应性，这些抗体的表位先前已定位在该蛋白上。这些区域包括氨基酸405至539（MAb B1）、1854至1879（MAb B4）、3506（MAb BA11）和4355（MAb BL3）。第五种抗体（MAb BL5）识别构象表达的表位。与来自各自血浆的LpB相比，病变部位的LpB免疫反应性显著降低，但MAb BA11识别的表位除外，该表位恰好位于低密度脂蛋白（LDL）受体结合位点。动脉粥样硬化血浆和健康血浆中LpB上四个连续表位的可及性相似，而动脉粥样硬化样本中LpB上构象表位的可及性降低。这些改变的免疫反应性与LpB化学成分的变化无关，因为所有制剂中的化学成分相当。关于颗粒的负电性、apoB片段化、免疫可及性和大小分布，变化似乎从健康血浆、动脉粥样硬化血浆到相应病变按以下顺序增加。结果证实了人类动脉粥样硬化病变中氧化修饰颗粒的一些结构特征，在较小程度上也证实了相应血浆中氧化修饰颗粒的结构特征，但更具体地证明了病变部位LpB的整体构象变化，这种变化可能始于血浆中。
