title: Conversion of a murine monoclonal antibody A13 targeting epidermal growth factor receptor to a human monoclonal antibody by guided selection.
abstract: Epidermal growth factor receptor (EGFR) is an attractive target for tumor therapy because it is overexpressed in the majority of solid tumors and the increase in receptor expression levels has been linked with a poor clinical prognosis. Also it is well established that blocking the interaction of EGFR and the growth factors could lead to the arrest of tumor growth and possibly result in tumor cell death. A13 is a murine monoclonal antibody (mAb) that specifically binds to various sets of EGFR-expressing tumor cells and inhibits EGF-induced EGFR phosphorylation. We isolated human immunoglobulin genes by guided selection based on the mAb A13. Four different human single chain Fvs (scFvs) were isolated from from hybrid scFv libraries containing a human VH repertoire with the VL of mAb A13 and a human VL repertoire with the VH of mAb A13. All the 4 scFvs bound to EGFR-expressing A431 cells. One scFv (SC414) with the highest affinity was converted to IgG1 (ER414). The ER414 exhibited ∼17 fold lower affinity compared to the A13 mAb. In addition the ER414 inhibited an EGF-induced tyrosine phosphorylation of EGFR with much lower efficacy compared to the A13 mAb and Cetuximab (Merck KgaA, Germany). We identified that the epitope of A13 mAb is retained in ER414. This approach will provide an efficient way of converting a murine mAb to a human mAb.
authors: Antibody Engineering Lab Central Research Center, Green Cross Corp. Yongin, Korea.
authors: Ki Hwan
authors: KH
authors: Chang
authors: Min Soo
authors: MS
authors: Kim
authors: Gwang Won
authors: GW
authors: Hong
authors: Yong Nam
authors: YN
authors: Shin
authors: Se Ho
authors: SH
authors: Kim
mesh_terms: D000818:Animals; D061067:Antibodies, Monoclonal, Humanized / Q000235:genetics* / Q000276:immunology / Q000627:therapeutic use; D000915:Antibody Affinity; D045744:Cell Line, Tumor; D019020:Directed Molecular Evolution / Q000379:methods*; D018604:Epitope Mapping; D000939:Epitopes / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000276:immunology; D006801:Humans; D007167:Immunotherapy; D051379:Mice; D009369:Neoplasms / Q000628:therapy*; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding; D012641:Selection, Genetic; D057127:Single-Chain Antibodies / Q000235:genetics* / Q000276:immunology / Q000627:therapeutic use
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000939:Epitopes; D057127:Single-Chain Antibodies; D066246:ErbB Receptors