A lightweight post-hoc filter that requires no re-docking and is directly compatible with existing AF3 prediction pipelines and transferable to other diffusion-based complex predictors, providing a practical quality-assurance layer for antibody epitope mapping in early-stage drug discovery.
Abstract
AlphaFold3 (AF3) predicts protein-complex structures from sequence with near-experimental accuracy on many targets, substantially lowering the cost of mechanistic and therapeutic discovery. However, application to antibody epitope prediction is hampered by an approximately 63% failure rate. Comparing successful and failed AF3 predictions across antibody-antigen and nanobody-antigen complexes, we found that failed predictions share a distinctive energetic signature: distorted CDR-loop geometries and elevated van der Waals strain at the interface. Building upon these observations, we developed a machine learning-based interface energy filtering framework, designated AFilter, capable of eliminating over 90% of erroneous predictions while retaining >90% of true positives. Compared with ipTM-based filtering, AFilter improved accuracy from 82.7% to 97.7% for nanobody-antigen complexes and from 79.4% to 96.3% for antibody-antigen complexes, while simultaneously raising the true positive rate from 69.8% to 96.4% and from 63.1% to 92.5%, respectively. When applied to NeuroMab antibodies of unknown structure, AFilter prioritized high-confidence epitope predictions that AF3 sampling alone could not reliably surface. As a lightweight post-hoc filter (<5% computational overhead) that requires no re-docking, AFilter is directly compatible with existing AF3 prediction pipelines and, in principle, transferable to other diffusion-based complex predictors, providing a practical quality-assurance layer for antibody epitope mapping in early-stage drug discovery.
This work evaluated ImmuneBuilder, IgFold, AlphaFold3, GRAMM, and dyMEAN on 50 non-redundant humanized antibody–antigen complexes using multiple retained predictions and paired statistical testing, finding all three antibody structure predictors were accurate.
Zeyuan Yu, Jilei Wu, Ziyao Ning et al.· Bioinformatics Advances· 0 citations
Adaptive immunity relies on T-cell receptor (TCR) recognition of non-self epitopes, short peptides presented by the Major Histocompatibility Complex (MHC) on the cell surface. Accurate computational prediction of TCR-epitope binding would unlock the development of targeted immunotherapies, such as cancer vaccines and TCR T cell therapies, while simultaneously deepening our fundamental understanding of self/nonself discrimination, pathogen recognition, and autoimmunity. We created an ensemble approach (enFoldX) that leverages structure prediction models such as AlphaFold3 to build sensitive binding predictors. enFoldX can distinguish T cell reactivity between peptides that differ by a single amino acid substitution, as needed for cancer neoantigens. enFoldX utilizes a customized highly parallelized workflow which allows us to produce ensembles of predicted protein structures at scale and train classifiers to infer reactivity based on distributions of engineered structure features and alignment confidence metrics. While state-of-the-art sequence-based approaches we evaluated could predict well for observed TCRs and epitopes close in sequence to training data, their applicability to novel sequences was limited. Conversely, our ensemble approach is the only model that showed true generalizability to novel datasets and even across species. Moreover, our ensemble approach outperforms the current co-folding methods which rely on predictions from the single top ranked structure. By leveraging the entire protein universe at scale, structure ensembles therefore enable classifiers that reflect physical free energies, providing a tractable path towards TCR T therapy design at the sensitivity required for cancer neoantigen discrimination and imparting lessons for a wide array of complex binding problems.
Olga Lyudovyk, Jonathan A. Levine, Melissa Pathil, Stephen Martis, Yuval Elhanati, Vinod P. Balachandran, Quaid Morris, Benjamin D. Greenbaum. enFoldX: AI classification of AlphaFold3-derived structural ensembles enables T cell specificity prediction [abstract]. In: Proceedings of AACR Drug Discovery and Development (AACR D3) Conference; 2026 Jul 21-24; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(14_Suppl):Abstract nr A028.
O. Lyudovyk, Jonathan A. Levine, M. Pathil et al.· Clinical Cancer Research· 0 citations
Adaptive immunity relies on T-cell receptor (TCR) recognition of non-self epitopes, short peptides presented by the Major Histocompatibility Complex (MHC) on the cell surface. Accurate computational prediction of TCR-epitope binding would unlock the development of targeted immunotherapies, such as cancer vaccines and TCR T cell therapies, while simultaneously deepening our fundamental understanding of self/nonself discrimination, pathogen recognition, and autoimmunity. We created an ensemble approach (enFoldX) that leverages structure prediction models such as AlphaFold3 to build sensitive binding predictors. enFoldX can distinguish T cell reactivity between peptides that differ by a single amino acid substitution, as needed for cancer neoantigens. enFoldX utilizes a customized highly parallelized workflow which allows us to produce ensembles of predicted protein structures at scale and train classifiers to infer reactivity based on distributions of engineered structure features and alignment confidence metrics. While state-of-the-art sequence-based approaches we evaluated could predict well for observed TCRs and epitopes close in sequence to training data, their applicability to novel sequences was limited. Conversely, our ensemble approach is the only model that showed true generalizability to novel datasets and even across species. Moreover, our ensemble approach outperforms the current co-folding methods which rely on predictions from the single top ranked structure. By leveraging the entire protein universe at scale, structure ensembles therefore enable classifiers that reflect physical free energies, providing a tractable path towards TCR T therapy design at the sensitivity required for cancer neoantigen discrimination and imparting lessons for a wide array of complex binding problems.
Olga Lyudovyk, Jonathan A. Levine, Melissa Pathil, Stephen Martis, Yuval Elhanati, Vinod P. Balachandran, Quaid Morris, Benjamin D. Greenbaum. enFoldX: AI classification of AlphaFold3-derived structural ensembles enables T cell specificity prediction [abstract]. In: Proceedings of AACR Drug Discovery and Development (AACR D3) Conference; 2026 Jul 21-24; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(14_Suppl):Abstract nr PR004.
O. Lyudovyk, Jonathan A. Levine, M. Pathil et al.· Clinical Cancer Research· 0 citations
It is found that, while AF3 can perform well in favourable settings, this performance is uneven across applications and its predictions and use of confidence metrics will depend strongly on the specific application area and must be interpreted with respect to training-set overlap.
O. Follonier, Yan Liu, Pablo Campomanes et al.· bioRxiv· 1 citation
The most recent methods substantially outperformed earlier ones, producing medium-or-better top-ranked models for approximately half of post-cutoff Fv complexes without templates or experimental restraints, and performing similarly on antigens with or without a close pre-cutoff homolog.
Minjae Park, Roman Nett, Brian M. Petersen et al.· bioRxiv· 0 citations
This work designs a biological prior-guided feature fusion framework that integrates pseudo-structural epitope knowledge and CDR-specific attention mechanisms via a mixture-of-experts architecture to effectively capture complex binding landscapes in antibody screening and drug residence time analysis.
G. Luo, Junkai Wang, Sizhe Zhang et al.· Bioinformatics· 0 citations