Affinity maturation by phage display.

Antibodies are indispensable tools for research, diagnostics, and therapy. However, sometimes antibodies with the most favourable specificity profile lack sufficient affinity for a desired application. Here, we describe a method to increase the affinity of recombinant scFv antibody fragments based on random mutagenesis and phage display under stringent conditions. Random mutations are inserted by performing several rounds of error-prone PCR. After construction of a mutated antibody gene library, affinity selection is performed by panning with washing conditions optimized for off-rate-dependent selection. Alternatively, panning in solution with competition can be used to enrich binders with improved binding properties.