Kusada Yu, Morizono Toru, Matsumoto-Takasaki Ayano, Sakai Keiko, Sato Shuma, Asanuma Hideki, Takayanagi Atsushi, Fujita-Yamaguchi Yoko
Department of Applied Biochemistry, Tokai University School of Engineering, Kanagawa 259-1292, Japan.
J Biochem. 2008 Jan;143(1):9-19. doi: 10.1093/jb/mvm192. Epub 2007 Oct 23.
Recombinant antibody consisting of the single-chain variable fragment (scFv) of 1H7 monoclonal antibody against insulin-like growth factor-I receptor (IGF-IR) and human IgG(1) Fc domain, scFv-Fc, has been found to exhibit inhibitory effects on breast cancer growth in vitro and in vivo [Li et al. (2000) Cancer Immunol. Immunother. 49, 243; Sachdev et al. (2003) Cancer Res. 63, 627]. Various types of scFvs from hybridomas producing 1H7 or 3B7 mAb were constructed using conventional phage display technology to further characterize the specificity and affinity of anti-IGF-IR mAbs. Binding studies performed using either phage antibodies or soluble scFv proteins to IGF-IR or insulin receptor (IR) and IGF-IR pre-incubated with mAbs suggested that (i) 1H7 and 3B7 bind to IGF-IR but do not bind to its structurally related IR, (ii) either the VL-VH or VH-VL sequence order does not apparently affect specificity for IGF-IR and (iii) 1H7 and 3B7 bind the independent epitopes, located in or near the N-terminal (440-514) and C-terminal (62-184) domains of the alpha subunit, respectively. This study not only revealed new information on binding regions for two anti-IGF-IR mAbs, but also provided the scFv genes as tools for further manipulation of the affinity or development of new IGF-IR-targeted cancer therapeutics.
由抗胰岛素样生长因子-I受体（IGF-IR）的1H7单克隆抗体的单链可变片段（scFv）与人IgG(1) Fc结构域组成的重组抗体scFv-Fc，已被发现可在体外和体内对乳腺癌生长产生抑制作用[Li等人（2000年），《癌症免疫学与免疫治疗》49卷，243页；Sachdev等人（2003年），《癌症研究》63卷，627页]。使用传统噬菌体展示技术构建了来自产生1H7或3B7单克隆抗体的杂交瘤的各种类型的scFv，以进一步表征抗IGF-IR单克隆抗体的特异性和亲和力。使用噬菌体抗体或可溶性scFv蛋白对IGF-IR或胰岛素受体（IR）进行结合研究，并将IGF-IR与单克隆抗体预孵育，结果表明：（i）1H7和3B7与IGF-IR结合，但不与其结构相关的IR结合；（ii）VL-VH或VH-VL序列顺序显然不影响对IGF-IR的特异性；（iii）1H7和3B7分别结合位于α亚基N端（440-514）和C端（62-184）结构域内或附近的独立表位。这项研究不仅揭示了两种抗IGF-IR单克隆抗体结合区域的新信息，还提供了scFv基因作为进一步操纵亲和力或开发新型IGF-IR靶向癌症治疗药物的工具。
