Construction and characterization of single-chain antibodies against human insulin-like growth factor-I receptor from hybridomas producing 1H7 or 3B7 monoclonal antibody.
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.
Kusada
Yu
Y
Department of Applied Biochemistry, Tokai University School of Engineering, Kanagawa 259-1292, Japan.
Morizono
Toru
T
Matsumoto-Takasaki
Ayano
A
Sakai
Keiko
K
Sato
Shuma
S
Asanuma
Hideki
H
Takayanagi
Atsushi
A
Fujita-Yamaguchi
Yoko
Y
D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology*; D000918:Antibody Specificity; D000939:Epitopes / Q000276:immunology; D006801:Humans; D006825:Hybridomas / Q000276:immunology*; D007135:Immunoglobulin Variable Region / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D019151:Peptide Library; D017526:Receptor, IGF Type 1 / Q000737:chemistry / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000939:Epitopes; D007135:Immunoglobulin Variable Region; D019151:Peptide Library; D017526:Receptor, IGF Type 1