Yumura Kyohei, Akiba Hiroki, Nagatoishi Satoru, Kusano-Arai Osamu, Iwanari Hiroko, Hamakubo Takao, Tsumoto Kouhei
Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8562, Japan.
Department of Bioengineering, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.
J Biochem. 2017 Sep 1;162(3):203-210. doi: 10.1093/jb/mvx023.
Bispecific antibody targeting of two different antigens is promising, but when fragment-based antibodies are used, homogeneous production is difficult. To overcome this difficulty, we developed a method using the SpyTag/SpyCatcher system in which a covalent bond is formed between the two polypeptides. Using this method, we constructed a bispecific antibody that simultaneously interacted with two different epitopes of roundabout homologue 1 (ROBO1), a membrane protein associated with cancer progression. A bispecific tetravalent antibody with an additional functional moiety was also constructed by using a dimeric biotin-binding protein. An interaction analysis of ROBO1-expressing cells and the recombinant antigen demonstrated the improved binding ability of the bispecific antibodies through spontaneous binding of the two antibody fragments to their respective epitopes. In addition, multivalency delayed dissociation, which is advantageous in therapy and diagnosis.
靶向两种不同抗原的双特异性抗体前景广阔，但使用基于片段的抗体时，难以实现均一生产。为克服这一困难，我们开发了一种利用SpyTag/SpyCatcher系统的方法，该系统可使两种多肽之间形成共价键。利用此方法，我们构建了一种双特异性抗体，它能同时与环绕同源物1（ROBO1，一种与癌症进展相关的膜蛋白）的两个不同表位相互作用。我们还通过使用二聚体生物素结合蛋白构建了一种带有额外功能部分的双特异性四价抗体。对表达ROBO1的细胞与重组抗原的相互作用分析表明，通过两个抗体片段与其各自表位的自发结合，双特异性抗体的结合能力得到了提高。此外，多价性延迟了解离，这在治疗和诊断中具有优势。
