Selection of Single Chain Antibody Fragments for Targeting Prostate Specific Membrane Antigen: A Comparison Between Cell-based and Antigen-based Approach

Prostate cancer (PCa) is the most frequently diagnosed cancer and the second most common cause of cancer related mortality in United States male population. ScFv fragments have different usefulness. For example they have small size, high perfusion rate, high yield of production and are non-immunogenic, thus they can be used for therapeutic purposes. In this project we used a synthetic human ScFv library for isolation of ScFv monoclonal antibodies against prostate specific membrane antigen. For this purpose, after five rounds of cell-panning, and also five rounds of antigen-panning with rPSMA specific anti- PSMA ScFv-phage particles were isolated. Phages with high affinity toward PSMA were selected and used for further analysis. Specificity and affinity of both ScFv to PSMA and LnCaP cell line examined by ELISA. Recombinant ScFv antibody isolated from cell-panning had higher specificity and affinity for both the antigen and LNCaP cell line. Our result demonstrated that ScFv antibody obtained by cell-panning can target PSMA antigen and cell lines.