De novo antibody design with SE(3) diffusion
Daniel Cutting, Frédéric A. Dreyer, David Errington, Constantin Schneider, Charlotte M. Deane
TL;DR
IgDiff introduces a SE(3) diffusion model for antibody backbone design, extending prior backbone diffusion methods to jointly generate paired heavy/light chain variable domains. Trained on ABB2-predicted structures from the Observed Antibody Space, IgDiff learns to produce designable, novel backbones and can predict compatible sequences via AbMPNN, enabling both unconditional and condition-specific design tasks. Across unconditioned and conditioned tasks, IgDiff demonstrates improved designability, CDR diversity, and canonical-cluster fidelity compared to RFDiffusion, with multiple experimentally validated antibodies expressed at high yield. The work highlights the viability of end-to-end, structure-based diffusion for antibody engineering and its potential to accelerate therapeutic antibody design and optimization.
Abstract
We introduce IgDiff, an antibody variable domain diffusion model based on a general protein backbone diffusion framework which was extended to handle multiple chains. Assessing the designability and novelty of the structures generated with our model, we find that IgDiff produces highly designable antibodies that can contain novel binding regions. The backbone dihedral angles of sampled structures show good agreement with a reference antibody distribution. We verify these designed antibodies experimentally and find that all express with high yield. Finally, we compare our model with a state-of-the-art generative backbone diffusion model on a range of antibody design tasks, such as the design of the complementarity determining regions or the pairing of a light chain to an existing heavy chain, and show improved properties and designability.
