Molecular reshaping of phage-displayed Interleukin-2 at beta chain receptor interface to obtain potent super-agonists with improved developability profiles

Engineered interleukin-2 (IL-2) variants yield better electrostatic complementarity to the IL-2 receptor beta chain and faster association kinetics leading to in vivo enhancement of immune effector responses and anti-tumor effects. Interleukin-2 (IL-2) engineered versions, with biased immunological functions, have emerged from yeast display and rational design. Here we reshaped the human IL-2 interface with the IL-2 receptor beta chain through the screening of phage-displayed libraries. Multiple beta super-binders were obtained, having increased receptor binding ability and improved developability profiles. Selected variants exhibit an accumulation of negatively charged residues at the interface, which provides a better electrostatic complementarity to the beta chain, and faster association kinetics. These findings point to mechanistic differences with the already reported superkines, characterized by a conformational switch due to the rearrangement of the hydrophobic core. The molecular bases of the favourable developability profile were tracked to a single residue: L92. Recombinant Fc-fusion proteins including our variants are superior to those based on H9 superkine in terms of expression levels in mammalian cells, aggregation resistance, stability, in vivo enhancement of immune effector responses, and anti-tumour effect.

Automated summary

Engineered interleukin-2 (IL-2) variants with improved electrostatic complementarity to the IL-2 receptor beta chain and faster association kinetics enhance immune effector responses and anti-tumor effects in vivo. These variants have an accumulation of negatively charged residues at the interface, providing better electrostatic complementarity and faster association kinetics. These findings differentiate them from previously reported superkines.