Production of Specific Anti-EGFR Single Chain Antibodies: A Promising Strategy in the Immunotherapy of EGFR Expressing Tumor Tissues

Background: EGFR (Epidermal growth factor receptor) is overexpressed in a number of cancers and plays an important role in several phenomena such as aggressiveness of tumor, decreased survival of the patient, and resistance to treatments such as hormone therapy, chemotherapy, and also radiation. Objectives: The aim of this study is to produce specific human single-chain antibodies against EGFR and evaluate its specificity against the immunodominant epitope in order to offer a new and efficient way in the treatment of EGFR-expressing tumor tissues. Methods: A phage antibody display library of scFv (single chain fragment variable) was panned against an immunodominant epitope of EGFR. In order to select the specific clones, DNA fingerprinting was performed and the common patterns were differentiated. ELISA (Enzyme linked immunosorbent assay) was done to confirm the panning results and show the specificity of the selected clones. Results: Two specific clones with the frequencies of 55% and 30% were differentiated. The clones showed positive ELISA with the corresponding epitope while no positive reaction was observed for negative controls: unrelated peptide, M13KO7 (helper phage), unrelated scFv and no peptide. Conclusions: Immunotherapy against cancer has been a new treatment strategy in the recent years. Small and high affinity scFvs have had a crucial role in this regard. The specific human anti-EGFR scFvs that were selected in this study and reacted with the corresponding epitopehave the potential to be applied as a blocking antibody for interfering with tumor growth in EGFR-expressing tumors. Further studies are needed to evaluate the effects of these antibodies in vitro and in vivo.