Phage display and selections on purified antigens.

The isolation of antibody fragments targeting proteins implicated in cancers and other diseases remains a crucial issue on targeted therapy or diagnostic tool development (Hoogenboom HR, Henderikx P, de Haard H. Adv Drug Deliv Rev 31 (1-2):5-31, 1998). In many case, the protein of interest, or a relevant portion of this protein such as its extracellular domain is available as purified protein. In such cases, phage display on purified antigen is an easy and fast way to select antibody fragment able to efficiently bind this antigen. However, the output of phage selection can vary significantly depending on the way to immobilize the purified antigen during selection. The following protocols describe the selection of phage antibody on purified antigen adsorbed on plastic, i.e. panning, or a selection in solution, using a biotinylated antigen as well as the corresponding screening produces, and gives hints on the advantage and drawbacks of each approach.