Protein engineering approaches for antibody fragments: directed evolution and rational design approaches

Abstract

The number of therapeutic antibodies in preclinical, clinical, or approved phases has been increasing exponentially, mostlydue to their known successes. Development of antibody engineering methods has substantially hastened the development of therapeuticantibodies. A variety of protein engineering techniques can be applied to antibodies to improve their affinity and/or biophysical propertiessuch as solubility and stability. Antibody fragments (where all or some parts of constant regions are eliminated while the essentialantigen binding region is preserved) are more suitable for protein engineering techniques because there are many in vitro screeningtechnologies available for antibody fragments but not full-length antibodies. Improvement of biophysical characteristics is importantin the early development phase because most antibodies fail at the later stage of development and this leads to loss of resources andtime. Here, we review directed evolution and rational design methods to improve antibody properties. Recent developments in rationaldesign approaches and antibody display technologies, and especially phage display, which was recently awarded the 2018 Nobel Prize,are discussed to be used in antibody research and development.