Random Fragment Libraries Displayed on Filamentous Phage

Phage-display peptide libraries (1 –4 ) have become powerful tools for identification and characterization of peptide mimicries that bind to specific selector molecules, such as antibodies (5 –7 ). The technology depends on random peptide sequences, displayed on the surface of filamentous bacteriophages, being allowed to interact with antibodies or other ligates. Ligates are usually immobilized on a solid support, such as a Petri dish, microplate, or microbeads, and binding phages are specifically enriched by several cycles of affinity selection (1 ,8 ,9 ). The displayed peptide responsible for binding to the antibody can be identified by directly sequencing the encoding insert in the genome of the recombinant phage. This random epitope library strategy has the potential advantage of being able to identify critical residues within an epitope (10 ) and of providing mimotopes (11 ), which can mimic discontinuous epitope structures (12 ,13 ). (See Chapters 17 and 18 of this volume for more details.)