Morelock M M, Rothlein R, Bright S M, Robinson M K, Graham E T, Sabo J P, Owens R, King D J, Norris S H, Scher D S
Department of Biochemistry, Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, Connecticut 06877-0368.
J Biol Chem. 1994 Apr 29;269(17):13048-55.
Construction of a series of chimeric antibodies (murine variable region and human constant region) derived from the murine antibody BIRR1, which recognizes intercellular adhesion molecule 1 (ICAM-1), has revealed differences in the relative binding abilities of the chimeric antibody to antigen. The chimeric antibodies show a ranking of their ability to compete with BIRR1 for antigen on the surface of cells with the order BIRR1 = cIgG1 (100%) > cIgG4 (30%) > cIgG2 (10%) as demonstrated by solid-phase competitive enzyme-linked immunosorbent assay. Papain digestion yielded Fab fragments that were purified to homogeneity. Competitive enzyme-linked immunosorbent assay showed that the chimeric and murine Fab binding constants were equivalent. A solution-phase binding assay (analyzed by size exclusion high performance liquid chromatography) between the intact mAbs and recombinant soluble ICAM-1 further established that the binding constants involving the Fab arms of the two antibodies were equivalent. In summary, the murine and chimeric anti-ICAM-1 antibodies bind cellular ICAM-1 with equivalent affinities but with differing avidities.
源自鼠源抗体BIRR1（可识别细胞间黏附分子1（ICAM-1））的一系列嵌合抗体（鼠源可变区和人源恒定区）的构建揭示了嵌合抗体与抗原相对结合能力的差异。固相竞争酶联免疫吸附测定表明，嵌合抗体在与细胞表面抗原竞争方面的能力排序为BIRR1 = cIgG1（100%）> cIgG4（30%）> cIgG2（10%）。木瓜蛋白酶消化产生了纯化至同质的Fab片段。竞争酶联免疫吸附测定表明，嵌合和鼠源Fab的结合常数相当。完整单克隆抗体与重组可溶性ICAM-1之间的溶液相结合测定（通过尺寸排阻高效液相色谱分析）进一步证实，两种抗体的Fab臂的结合常数相当。总之，鼠源和嵌合抗ICAM-1抗体以相当的亲和力但不同的亲和力结合细胞ICAM-1。
