Nishimura Y, Yokoyama M, Araki K, Ueda R, Kudo A, Watanabe T
Cancer Res. 1987 Feb 15;47(4):999-1005.
A human-mouse chimeric antibody constructed in the present study was specific for a human tumor-associated antigen, common acute lymphocytic leukemia antigen. The antibody consisted of human heavy and light chain constant domains (gamma 1 and kappa type) and mouse heavy and light chain variable domains, which were derived from human plasma cell leukemia line (ARH77) and mouse hybridoma cells (NL-1) specific for common acute lymphocytic leukemia antigen, respectively. The artificially fused immunoglobulin molecules were produced in mouse myeloma cells, X63Ag8.653 which were transformed with the chimeric heavy and light chain genes formed by joining the corresponding gene segments in vitro at the J-C introns. The human heavy chain enhancer element was ligated tot he chimeric heavy and light chain genes, and this enhancer appeared to be obligatory for the efficient production of the chimeric antibody molecules. The stably transformed cells secreted the chimeric antibody, which specifically bound a common acute lymphocytic leukemia antigen expressing cell line. The amount of the chimeric antibody produced (10-30 micrograms/ml in the serum-free medium) was comparable to that made by murine hybridoma line, NL-1. The molecular weight of the chimeric heavy chain molecules was reduced from 54,000 to 50,000 upon treatment with tunicamycin, suggesting that the peptide was normally glycosylated in the transformants. The chimeric antibody exhibited complement-dependent cytotoxicity, in which glycosylation is thought to be indispensable. The antibody also mediated antibody-dependent cell-mediated cytotoxicity to the human target cells. The antibody-dependent cell-mediated cytotoxicity activity of the chimeric antibody was twice that of the murine NL-1 monoclonal antibody when human peripheral blood mononuclear cells were used as effectors.
本研究构建的人鼠嵌合抗体对人肿瘤相关抗原——普通急性淋巴细胞白血病抗原有特异性。该抗体由人重链和轻链恒定区（γ1和κ型）以及鼠重链和轻链可变区组成，它们分别来源于人浆细胞白血病细胞系（ARH77）和对普通急性淋巴细胞白血病抗原有特异性的鼠杂交瘤细胞（NL-1）。人工融合的免疫球蛋白分子在小鼠骨髓瘤细胞X63Ag8.653中产生，该细胞用通过在J-C内含子处体外连接相应基因片段形成的嵌合重链和轻链基因进行转化。人重链增强子元件连接到嵌合重链和轻链基因上，并且该增强子似乎是高效产生嵌合抗体分子所必需的。稳定转化的细胞分泌嵌合抗体，该抗体特异性结合表达普通急性淋巴细胞白血病抗原的细胞系。产生的嵌合抗体量（在无血清培养基中为10 - 30微克/毫升）与鼠杂交瘤细胞系NL-1产生的量相当。用衣霉素处理后，嵌合重链分子的分子量从54,000降至50,000，这表明该肽在转化体中正常糖基化。嵌合抗体表现出补体依赖性细胞毒性，其中糖基化被认为是必不可少的。该抗体还介导对人靶细胞的抗体依赖性细胞介导的细胞毒性。当用人外周血单个核细胞作为效应细胞时，嵌合抗体的抗体依赖性细胞介导的细胞毒性活性是鼠NL-1单克隆抗体的两倍。
