7KQ7

Crystal structure of IL21R in complex with an antibody Fab fragment

Summary for 7KQ7

• Entry DOI: 10.2210/pdb7kq7/pdb
• Descriptor: Antibody heavy chain, Antibody light chain, Interleukin-21 receptor, ... (4 entities in total)
• Functional Keywords: cytokine receptor, protein binding, protein binding-immune system complex, protein binding/immune system
• Biological source: Rattus norvegicus; More
• Total number of polymer chains: 3
• Total formula weight: 72262.60

Authors

Mosyak, L.,Svenson, K. (deposition date: 2020-11-13, release date: 2021-04-07, Last modification date: 2024-10-23)

Primary citation

Campbell, S.M.,DeBartolo, J.,Apgar, J.R.,Mosyak, L.,McManus, V.,Beyer, S.,Bennett, E.M.,Lambert, M.,Cunningham, O.
Combining random mutagenesis, structure-guided design and next-generation sequencing to mitigate polyreactivity of an anti-IL-21R antibody.
Mabs, 13:1883239-1883239, 2021

PubMed Abstract: Despite substantial technological advances in antibody library and display platform development, the number of approved biotherapeutics from displayed libraries remains limited. , 20-50% of peripheral B cells undergo a process of receptor editing, which modifies the variable and junctional regions of light chains to delete auto-reactive clones. However, antibody evolution relies primarily on interaction with antigen, with no in-built checkpoints to ensure that the selected antibodies have not acquired additional specificities or biophysical liabilities during the optimization process. We had previously observed an enrichment of positive charge in the complementarity-determining regions of an anti-IL-21 R antibody during affinity optimization, which correlated with more potent IL-21 neutralization, but poor pharmacokinetics (PK). There is an emerging body of data that has correlated antibody nonspecificity with poor PK , and established a series of screening assays that are predictive of this behavior. In this study we revisit the challenge of developing an anti-IL-21 R antibody that can effectively compete with IL-21 for its highly negatively charged paratope while maintaining favorable biophysical properties. deselection methods that included an excess of negatively charged membrane preparations, or deoxyribonucleic acid, during phage selection of optimization libraries were unsuccessful in avoiding enrichment of highly charged, nonspecific antibody variants. However, a combination of structure-guided rational library design, next-generation sequencing of library outputs and application of linear regression models resulted in the identification of an antibody that maintained high affinity for IL-21 R and exhibited a desirable stability and biophysical profile.

PubMed: 33557673
DOI: 10.1080/19420862.2021.1883239

Experimental method

X-RAY DIFFRACTION (2.203 Å)