Isolation of human prostate cancer cell reactive antibodies using phage display technology

Here we describe a phage display strategy for the selection of rabbit monoclonal antibodies that recognize cell surface tumor-associated antigens expressed in prostate cancer. Two immune rabbit/human chimeric Fab libraries were displayed on phage and used to search for tumor-associated antigens by panning on DU145 human prostate cancer cells. For this, we developed a novel whole-cell panning protocol with two negative selection steps designed to remove antibodies reacting with common antigens. After three rounds of subtractive panning, a majority of clones bound to DU145 cells as detected by flow cytometry. Among these, we identified several clones that bound selectively to DU145 cells but not to primary human prostate epithelial cell line PrEC. In summary, our work demonstrates the potential of immune rabbit antibody libraries for target discovery in general and the identification of cell surface tumor-associated antigens in particular.