Lossless affinity, optimized humanized sequence
Your antibodies can be further developed to enhance binding properties using affinity maturation. These antibodies can also be optimized to a humanized sequence. We use the principles of light chain shuffling and oligonucleotide-directed mutagenesis to improve binding affinities and human homology. Binding affinity can be improved by 10-1000-fold. Antibodies can be fully humanized without loss of affinity.
Affinity maturation
Our in vitro affinity maturation service typically performs several rounds of affinity-driven phage display selections to generate antibodies with enhanced binding. The technology has been successfully used to optimize antibodies and antibody fragments to create antibodies with sub-nanomolar binding affinities. In addition, chain shuffling can be used to increase the genetic diversity and the numbers of affinity matured antibodies. Using oligonucleotide-directed mutagenesis, the antibody variable regions are mutagenized by the targeted randomization of certain positions at a defined diversity. The antibodies of resultant libraries are then interrogated in a particular manner to isolate antibody variants with improved binding properties. Engineering of the antibody can improve affinity, potency in functional assays, developability, introduce cross-species binding and remove binding to related target family members. Libraries can be screened using standard phage display or mammalian display technologies. Both technologies have proven to deliver antibodies with improved affinities. Using mammalian display includes the screening of millions of clones in an IgG format and selecting leads in a mammalian background giving developability profiles favourable for downstream CMC. To date, our technologies have shown to fix “broken antibodies” in a number of studies, allowing antibodies with poor biophysical properties to be optimised for eventual cell line development.
Humanization
Using the sequence of the parental antibody, the closest human germline is chosen based on CDR canonical fold structures. Phage display libraries containing variants in which FR/CDR positions are targeted in a binary substitution manner (residue is either the non-human or human residue) are generated. Libraries are interrogated under specific conditions (affinity-driven selections) and hundreds of clones screened for biding properties. The new antibody sequences are ranked by percentage of human identity and homology, and by off-rate. The advantages of the binary mutagenesis strategy are the reduction of aberrant clones and enrichment of functional clones in the humanized library.
