Whether these can be used in diabetes prevention needs to be carefully evaluated in animal models before use in future clinical assays.—Calviño-Sampedro, C., Gomez-Tourino, I., Cordero, O. J., Reche, P. A., Gómez-Perosanz, M., Sánchez-Trincado, J. L., Rodríguez, M. Á., Sueiro, A. M., Viñuela, J. E., Calviño, R. V. Naturally presented HLA class I–restricted epitopes from the neurotrophic factor S100-β are targets of the autoimmune response in type 1 diabetes. Here, S100B is linked to diabetes mellitus.