PTPRN and type 1 diabetes mellitus: Moreover, these IA-2 and GAD65 DR4-restricted epitopes encompassed T-cell epitopes for HLA class I–restricted CD8+ T cells in T1D [10], for which we coined the term “combitope.” We hypothesized that T cells activated by RV could trigger or exacerbate islet autoimmunity by molecular mimicry with IA-2 or GAD65 epitopes [7–9].