Identification and characterisation of anti-IL-13 inhibitory single domain antibodies provides new insights into receptor selectivity and attractive opportunities for drug discovery

Frontiers in Immunology

Immunology

Helena Wright¹  Kayleigh Walker¹  Chitra Seewooruthun¹  Gareth Hall¹  Mark D. Carr¹  Frederick W. Muskett¹  Rachel Holyfield¹  Roberta Baravalle¹  Christine Prosser²  Jacqueline Kalms²  Andy Merritt³  Alastair D. G. Lawson⁴  Anthony Scott-Tucker⁴  Alistair Henry⁴ 

[1] Leicester Institute of Structural and Chemical Biology, and Department of Molecular and Cell Biology, University of Leicester, Leicester, United Kingdom;Leicester Institute of Structural and Chemical Biology, and Department of Molecular and Cell Biology, University of Leicester, Leicester, United Kingdom;UCB Biopharma, UCB Pharma, Slough, United Kingdom;LifeArc, Centre for Therapeutics Discovery, Stevenage Bioscience Catalyst, Stevenage, United Kingdom;UCB Biopharma, UCB Pharma, Slough, United Kingdom;

关键词: interleukin-13;    single domain antibodies;    VHH;    receptor signalling;    receptor selectivity;    allosteric regulation;   

DOI  :  10.3389/fimmu.2023.1216967

 received in 2023-05-04, accepted in 2023-06-19,  发布年份 2023

来源: Frontiers

【 摘 要 】

Interleukin-13 (IL-13) is a cytokine involved in T-cell immune responses and is a well validated therapeutic target for the treatment of asthma, along with other allergic and inflammatory diseases. IL-13 signals through a ternary signalling complex formed with the receptors IL-13Rα1 and IL-4Rα. This complex is assembled by IL-13 initially binding IL-13Rα1, followed by association of the binary IL-13:IL-13Rα1 complex with IL-4Rα. The receptors are shared with IL-4, but IL-4 initially binds IL-4Rα. Here we report the identification and characterisation of a diverse panel of single-domain antibodies (VHHs) that bind to IL-13 (KD 40 nM-5.5 μM) and inhibit downstream IL-13 signalling (IC50 0.2-53.8 μM). NMR mapping showed that the VHHs recognise a number of epitopes on IL-13, including previously unknown allosteric sites. Further NMR investigation of VHH204 bound to IL-13 revealed a novel allosteric mechanism of inhibition, with the antibody stabilising IL-13 in a conformation incompatible with receptor binding. This also led to the identification of a conformational equilibrium for free IL-13, providing insights into differing receptor signalling complex assembly seen for IL-13 compared to IL-4, with formation of the IL-13:IL-13Rα1 complex required to stabilise IL-13 in a conformation with high affinity for IL-4Rα. These findings highlight new opportunities for therapeutic targeting of IL-13 and we report a successful 19F fragment screen of the IL-13:VHH204 complex, including binding sites identified for several hits. To our knowledge, these 19F containing fragments represent the first small-molecules shown to bind to IL-13 and could provide starting points for a small-molecule drug discovery programme.

【 授权许可】

Unknown   
Copyright © 2023 Walker, Baravalle, Holyfield, Kalms, Wright, Seewooruthun, Muskett, Scott-Tucker, Merritt, Henry, Lawson, Hall, Prosser and Carr