Defense Finder
Explore and analyse prokaryotic anti-phage defense systems — freely, without login.
Defense Finder Webservice
Detect anti-phage defense systems in proteic or nucleic FASTA sequences — no login required.
Accepts both proteic and nucleic FASTA files — format is detected automatically.
A run typically takes a couple of minutes. Multiple analyses can run simultaneously.
Results appear in the Results DefenseFinder panel on the left.
Errors most often arise from incorrect input formats — ensure you use a valid FASTA file.
Predicted Anti-phage Systems
BLAST your proteins against a database of sequences predicted by language models (Mordret et al.).
Search your protein sequence(s) against a database of predicted defense systems (Mordret et al.).
Under the hood, runs Diamond — a faster BLAST — for rapid sequence alignment.
Provide a protein FASTA file with one or multiple sequences.
Results appear under Results Predicted systems — a run takes a couple of minutes.
Cite this service
If you are using DefenseFinder please cite:
Systematic and quantitative view of the antiviral arsenal of prokaryotes
Tesson F., Hervé A., Touchon M., d'Humières C., Cury J., Bernheim A., Nature Communication, 2022
MacSyFinder v2: Improved modelling and search engine to identify molecular systems in genomes
Néron, B; Denise, R; Coluzzi, C; Touchon, M; Rocha, E.P.C.; Abby, S.S., Peer Community Journal, 2023
A Comprehensive Resource for Exploring Antiphage Defense: DefenseFinder Webservice, Wiki and Databases
Tesson, F., Planel, R., Egorov, A., Georjon, H., Vaysset, H., Brancotte, B., Néron, B., Mordret, E., Bernheim, A., Atkinson, G., & Cury, J., Preprint, 2024
Protein and genomic language models uncover the unexplored diversity of bacterial immunity
Mordret, E., Hervé A., Tesson, F., Vaysset, H., Clabby, T., Loubat, A., Shomar, H., Planel, R., Lavenir, R., Cury, J., Bernheim, A., Science, 2026