Theolis R, Weech P K, Marcel Y L, Milne R W
Arteriosclerosis. 1984 Sep-Oct;4(5):498-509. doi: 10.1161/01.atv.4.5.498.
In the hope of obtaining useful probes to study the structure of human apolipoprotein B (apo B), we characterized monoclonal antibodies against low density lipoprotein (LDL). We examined the distribution of their corresponding antigenic determinants on tryptic fragments of LDL separated by monodimensional (SDS) or two-dimensional electrophoresis. Each antibody reacted with several different fragments even when the proteolysis was apparently complete. A peptide of 125,000 daltons was the smallest fragment recognized by all the antibodies. The antibody, 2D8, which cross-reacts with apo B-48 and 3A8 which blocks the LDL pathway both reacted with the same 43,000 dalton fragment. Two other antibodies, 3F5 and 4G3, previously shown to be close together in LDL, also appeared close together in the primary structure of apo B. A determinant present on apo B-26 (1D1) was dissociated from all others examined on fragments of less than 125,000. Similarities in the patterns of reactivities with LDL-tryptic fragments between certain monoclonal antibodies and the lectins Concanavalin A and Limax flavus agglutinin indicated the proximity of the corresponding antigenic determinants to carbohydrate moieties. Competition studies suggested that the two major carbohydrate chains of LDL do not participate in the determinants themselves.
为了获得用于研究人载脂蛋白B（apo B）结构的有用探针，我们对针对低密度脂蛋白（LDL）的单克隆抗体进行了表征。我们研究了其相应抗原决定簇在通过一维（SDS）或二维电泳分离的LDL胰蛋白酶片段上的分布。即使蛋白水解明显完全，每种抗体仍与几个不同的片段发生反应。一个125,000道尔顿的肽是所有抗体识别的最小片段。与apo B - 48发生交叉反应的抗体2D8和阻断LDL途径的抗体3A8均与相同的43,000道尔顿片段发生反应。另外两种抗体3F5和4G3，先前显示在LDL中彼此靠近，在apo B的一级结构中也显得彼此靠近。apo B - 26上存在的一个决定簇（1D1）与在小于125,000的片段上检测的所有其他决定簇分离。某些单克隆抗体与凝集素伴刀豆球蛋白A和黄斑海蜗牛凝集素与LDL - 胰蛋白酶片段的反应模式相似，表明相应抗原决定簇与碳水化合物部分接近。竞争研究表明，LDL的两条主要碳水化合物链本身不参与这些决定簇。
