An expanded genetic code facilitates antibody chemical conjugation involving the lambda light chain
An expanded genetic code facilitates antibody chemical conjugation involving the lambda light chain
复制标题
扩展的遗传密码有助于涉及 lambda 轻链的抗体化学缀合
DOI：
10.1016/j.bbrc.2021.02.005
复制
发表时间：
2021
影响因子：
3.1
通讯作者：
Shiraishi Yasuhisa
中科院分区：
文献类型：
--
作者：
Kato Akifumi;Ohtake Kazumasa;Tanaka Yoshitaka;Yokoyama Shigeyuki;Sakamoto Kensaku;Shiraishi Yasuhisa
目前批准的大多数治疗性抗体是免疫球蛋白γ（IgG）κ同种型，这为IgGλ在医学治疗中的使用留下了巨大的机会。将设计氨基酸掺入抗体中使得能够有效和精确地制造抗体化学缀合物。已在人κ-轻链（LCκ）的恒定结构域中探索了有用的缀合位点，LC κ与其LCλ对应物在氨基酸序列上的同一性不超过38%。在本研究中，我们使用扩展的遗传密码将N ε-（o-叠氮基苄氧羰基）-l-赖氨酸（o-Az-Z-Lys）位点特异性地修饰到IgGλ的抗原结合片段（Fab）中，即cixutumumab。发现LCλ恒定结构域中的十个位点支持利用生物正交叠氮化学的有效化学缀合。大多数鉴定的位置位于两种轻链同种型之间不同的区域，因此对λ同种型具有特异性。最后，将o-Az-Z-Lys掺入到cixutumumab和曲妥珠单抗的Fab片段中以使它们化学联合收割机结合;所得的双特异性Fab二聚体显示出针对癌细胞系的强拮抗活性。目前的结果将化学缀合方法的实用性扩展到整个人源化抗体谱，包括λ同种型。
Most of the currently approved therapeutic antibodies are of the immunoglobulin gamma (IgG) κ isotype, leaving a vast opportunity for the use of IgGλ in medical treatments. The incorporation of designer amino acids into antibodies enables efficient and precise manufacturing of antibody chemical conjugates. Useful conjugation sites have been explored in the constant domain of the human κ-light chain (LCκ), which is no more than 38% identical to its LCλ counterpart in amino acid sequence. In the present study, we used an expanded genetic code for site-specifically incorporatingNε-(o-azidobenzyloxycarbonyl)-l-lysine (o-Az-Z-Lys) into the antigen-binding fragment (Fab) of an IgGλ, cixutumumab. Ten sites in the LCλ constant domain were found to support efficient chemical conjugation exploiting the bio-orthogonal azido chemistry. Most of the identified positions are located in regions that differ between the two light chain isotypes, thus being specific to the λ isotype. Finally,o-Az-Z-Lys was incorporated into the Fab fragments of cixutumumab and trastuzumab to chemically combine them; the resulting bispecific Fab-dimers showed a strong antagonistic activity against a cancer cell line. The present results expand the utility of the chemical conjugation method to the whole spectrum of humanized antibodies, including the λ isotype.