Affinity maturation is the process to improve antibody affinity for an antigen. In vivo, natural affinity maturation by the immune system takes place by somatic hypermutation and clonal selection. In vitro, in the laboratory affinity maturation can be obtained by mutation and selection.

Creative Biolabs have gained extensive experience in antibody affinity maturation. We usually take scFv as the antibody format in affinity maturation. Also, a monovalent display phagemid system is used to reduce the avidity effects during antigen-binding screening. We also provide affinity maturation services for nanobodies (single domain antibodies). Two methods, untargeted mutagenesis and oligonucleotide-directed mutagenesis, are employed to construct random or defined sub-libraries to introduce a large number of mutants of the original antibody. Antibody binders of higher affinity are then selected by increasing the screening stringency. By constructing a series of sub-libraries of a scFv/Fab antibody, our proprietary protocol allows increase of the affinity of the scFv antibodies from 10 [-8] to 10 [-9]. We have successfully obtained a scFv antibody that has an extremely high affinity of 10 [-12], whose binding to the antigen is essentially irreversible. 

http://www.creative-biolabs.com/antibody-affinity-maturation.html