Fig. 1.

Proinsulin-derived epitopes recognized by human islet-infiltrating CD4⁺ T cells. The boxes indicate regions of human proinsulin for which CD4⁺ T cell epitopes have been mapped examining human islet-infiltrating T-cells from multiple donors with T1D. Two-colored boxes indicate hybrid insulin peptides (HIPs) and are placed to align with the proinsulin part of the epitope, with the other half of the HIP is as labeled: islet amyloid polyprotein (IAPP), neuropeptide Y (NP-Y), insulin A-chain (INS-A). Horizontal lines indicate the epitopes described in each study (references shown on the right). For epitopes that an HLA restriction have been determined, the restricting HLA allele is shown within the box. In some cases, several clones have been isolated that recognize the same, or very similar epitopes indicated by the numbers (i.e., ×2). The number of unique TCRαβ sequences expressed by these clones is shown in parenthesis