Takeda S, Naito T, Hama K, Noma T, Honjo T
Nature. 1985;314(6010):452-4. doi: 10.1038/314452a0.
The specificity of monoclonal antibodies provides a powerful diagnostic and therapeutic tool in investigating human neoplasia. Radiological scanning and immunotherapy with mouse tumour-specific monoclonal antibodies have been applied to patients with some success, but a major problem is the neutralization of the mouse antibody induced by repeated administration of heterologous antibodies. To avoid or reduce such immune reactions, chimaeric immunoglobulins consisting of mouse variable (V) and human constant (C) regions can be synthesized. We have constructed a recombinant retrovirus DNA carrying genomic heavy-chain (H) variable-diversity joining (VH-D-JH) and C gamma 1 genes from different species and show here that the chimaeric intervening sequences are spliced out precisely. This procedure provides a useful method to construct the chimaeric mouse-human immunoglobulin gene to be expressed in Escherichia coli, yeast and animal cells. Unexpectedly, a hidden splice donor site in the 5'-flanking region of a human VH gene is used in place of the donor site of the leader sequence exon, resulting in the formation of the V region without the leader sequence.
单克隆抗体的特异性为研究人类肿瘤提供了一种强大的诊断和治疗工具。放射扫描以及用小鼠肿瘤特异性单克隆抗体进行免疫治疗已应用于患者并取得了一定成功，但一个主要问题是反复给予异源抗体可诱导小鼠抗体的中和作用。为避免或减少此类免疫反应，可合成由小鼠可变（V）区和人恒定（C）区组成的嵌合免疫球蛋白。我们构建了一种携带来自不同物种的基因组重链（H）可变区-多样性连接区（VH-D-JH）和Cγ1基因的重组逆转录病毒DNA，并在此表明嵌合的间隔序列被精确剪接出去。该程序为构建将在大肠杆菌、酵母和动物细胞中表达的嵌合小鼠-人免疫球蛋白基因提供了一种有用的方法。出乎意料的是，人VH基因5'侧翼区的一个隐藏剪接供体位点取代了前导序列外显子的供体位点，导致形成没有前导序列的V区。
