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Updated: May 27, 2026
Generation of Discriminative Human Monoclonal Antibodies from Rare Antigen-specific B Cells Circulating in Blood
Published on: February 6, 2018
Conversion of a murine monoclonal antibody A13 targeting epidermal growth factor receptor to a human monoclonal
Ki Hwan Chang1, Min Soo Kim, Gwang Won Hong
1Antibody Engineering Lab Central Research Center, Green Cross Corp. Yongin, Korea.
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.
Insights
Researchers converted a mouse antibody targeting epidermal growth factor receptor (EGFR) into a human antibody. This new human antibody retains the EGFR binding epitope, offering a potential therapeutic strategy for EGFR-overexpressing tumors.
Area of Science:
- Oncology
- Immunology
- Biotechnology
Background:
- Epidermal growth factor receptor (EGFR) is overexpressed in many solid tumors, correlating with poor prognosis.
- Blocking EGFR signaling can inhibit tumor growth and induce cancer cell death.
- Murine monoclonal antibody (mAb) A13 targets EGFR and inhibits its phosphorylation.
Purpose of the Study:
- To isolate human immunoglobulin genes based on the A13 mAb.
- To develop a human antibody with therapeutic potential against EGFR-overexpressing tumors.
- To establish an efficient method for converting murine mAbs to human mAbs.
Main Methods:
- Guided selection was used to isolate human single-chain Fvs (scFvs) from hybrid scFv libraries.
- scFvs were generated using a human VH repertoire with A13's VL and a human VL repertoire with A13's VH.
- The highest affinity scFv (SC414) was converted to a human IgG1 antibody (ER414).
Main Results:
- Four human scFvs were isolated, all binding to EGFR-expressing A431 cells.
- The human IgG1 antibody ER414 showed approximately 17-fold lower affinity than the A13 mAb.
- ER414 demonstrated significantly lower efficacy in inhibiting EGF-induced EGFR tyrosine phosphorylation compared to A13 and Cetuximab.
- The epitope recognized by A13 mAb was confirmed to be retained in ER414.
Conclusions:
- The study successfully converted a murine anti-EGFR mAb (A13) into a human antibody (ER414).
- While ER414's affinity and efficacy were reduced compared to the parent mAb, it retains the target epitope.
- This approach provides an effective strategy for developing humanized antibodies from murine monoclonal antibodies for cancer therapy.
