Extensive sequence and structural evolution of Arginase 2 inhibitory antibodies enabled by an unbiased approach to affinity maturation
| Autor: | Ellen Gowans, Stuart W. Haynes, Mark D. Carr, Stephanie Ryman, Maria A T Groves, Daniel Burschowsky, Tristan J Vaughan, Alexandra Addyman, Vincenzo Cerundolo, Agata Diamandakis, Chitra Seewooruthun, Yoko Shibata, Louise H. Slater, Sarah V. Holt, Denice T Y Chan, Sebastian Fiedler, Jessica Whitehouse, Robert W. Wilkinson, Lesley Jenkinson, Mark Austin, Michelle Barnard |
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| Rok vydání: | 2020 |
| Předmět: |
inhibitory antibodies
Antibody Affinity Computational biology Biochemistry Antibodies Affinity maturation Antigen Humans ARG2 affinity maturation Multidisciplinary Arginase antibody engineering biology ribosome display Chemistry Biological Sciences Complementarity Determining Regions Arginase 2 Ribosome display biology.protein Paratope Binding Sites Antibody Antibody Systematic evolution of ligands by exponential enrichment |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.1919565117 |
| Popis: | Significance We describe an antibody optimization strategy that seeks to overcome the restrictive nature of existing affinity-maturation methods, by rapidly exploring a vast sequence space in an unbiased manner through application of PCR techniques and ribosome display. We exemplified the significance of this method by contrasting the crystal structure of the parent and optimized antibodies bound to Arginase 2, which revealed a striking reorientation of the binding paratope, concurrent with distinct improvements in inhibitory potency and binding properties. The nature and magnitude of the epitope expansion was extraordinary and unlikely to have been produced through conventional affinity-maturation methods. This innovative approach demonstrates broad applicability to the optimization of candidate therapeutic antibodies, even those less amenable to CDRH3 targeting. Affinity maturation is a powerful technique in antibody engineering for the in vitro evolution of antigen binding interactions. Key to the success of this process is the expansion of sequence and combinatorial diversity to increase the structural repertoire from which superior binding variants may be selected. However, conventional strategies are often restrictive and only focus on small regions of the antibody at a time. In this study, we used a method that combined antibody chain shuffling and a staggered-extension process to produce unbiased libraries, which recombined beneficial mutations from all six complementarity-determining regions (CDRs) in the affinity maturation of an inhibitory antibody to Arginase 2 (ARG2). We made use of the vast display capacity of ribosome display to accommodate the sequence space required for the diverse library builds. Further diversity was introduced through pool maturation to optimize seven leads of interest simultaneously. This resulted in antibodies with substantial improvements in binding properties and inhibition potency. The extensive sequence changes resulting from this approach were translated into striking structural changes for parent and affinity-matured antibodies bound to ARG2, with a large reorientation of the binding paratope facilitating increases in contact surface and shape complementarity to the antigen. The considerable gains in therapeutic properties seen from extensive sequence and structural evolution of the parent ARG2 inhibitory antibody clearly illustrate the advantages of the unbiased approach developed, which was key to the identification of high-affinity antibodies with the desired inhibitory potency and specificity. |
| Databáze: | OpenAIRE |
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