Production of human single-chain fragment antibody (ScFv) against human epidermal growth factor receptor-2 (HER-2) by phage display technology.

Breast cancer with more than 1.7 million diagnoses per year has been known as one of the most prevalent cancers among women worldwide. Despite the availability of advanced treatment options, cancer progression and metastasis is observed in 20% of patients. Human epidermal growth factor receptor-2 (HER-2) is considered as an important prognostic and diagnostic tumor marker for breast cancer. While HER-2 is expressed on the surface of normal cells, its overexpression occurs in 20-25% on breast cancer tumor cells. This type of tumor which is referred to as HER-2+ is the most aggressive type of breast cancer and shows more resistance to radiotherapy. Single-chain fragment antibodies (ScFvs) offer several advantages in comparison to conventional whole antibodies due to their small size. Particularly, ScFv fragments show improved diffusion and solid tumor penetration. In this study, a human ScFv antibody library was used to isolate anti-HER-2 ScFv antibodies through cell panning and mix antigen-cell panning strategies. Analysis of the binding activity and specificity of isolated ScFv antibodies against HER-2-expressing cell lines and recombinant HER-2 antigen indicated the higher efficiency of the cell panning strategy in isolation of ScFv antibody fragments.