Protein A-Specific Enrichment of Insert-containing Phage in Antibody Phage Display Library

Background and purpose: Antibody phage display library is a powerful in vitro technology for production of recombinant antibody fragments against a wide variety of antigens. However, the presence of insert-free clones in the phage libraries limited the specific enrichment of antibody fragments in many studies. The aim of this study was to protein A-aided recovery of insert-containing phages in antibody phage display library. Materials and methods: Tomlinson antibody library was prepared according to the standard protocol. Three rounds of panning were performed in two independent groups on VERO/HER2 cells, considering a step of protein A-aided phage precipitation at the end of each round only in one group. The efficiency of this method was evaluated on the selected clones using PCR and phage-Elisa. Results: The results of PCR showed that 87% of clones contained insert after three rounds of panning using protein A-recovered phages while in the control group only 41% of clones contained insert. Also, the results of phage-ELISA showed specific enrichment of anti-HER2 antibodies in protein Atreated group. Conclusion: This method provided a simple and effective way for selective enrichment of antibody fragments in the phage display antibody libraries.