Relative abundance of insulin peptides isolated from blood leukocytes. The data show the relative abundance of each individual peptide sequence derived from the Ins2B:9-23 and Ins1C:51-61 families depicted in Table 1. LC-MS/MS data files of the leukocyte MHC-II peptidome were loaded into Skyline for quantification of peptides covering the Ins2B:9-23 and Ins1C:51-61 families, and the resulting peak areas were exported, normalized based on the total ion current, and log2-transformed. The bars represent the normalized log2 abundance of the indicated peptides. The results of the no glucose condition represent a single experiment analyzing 3 × 10⁷ blood leukocytes from 19 NOD mice without glucose challenge. The data of the glucose challenge condition are from two independent experiments including 20 (3 × 10⁷ cells) and 40 (7.5 × 10⁷ cells) NOD mice after glucose injection, respectively. In peptide sequences, the lowercase c denotes the oxidation of cysteine to cysteic acid, and the lowercase q denotes the deamidation of glutamine.