Extended Data Fig. 1: Characterization of NOD mice carrying different combinations of I-A^g7 b56/57 polymorphisms.

(a) Genomic DNA sequence surrounding I-A^g7 b56/57 of NOD mice carrying the wild type (HS), PD or frame shift (KO) mutation. (b) MHC-II expression on B cells from I-A^g7-WT/WT (n = 11), I-A^g7-KO/WT (n = 9) and I-A^g7-KO/KO (n = 8) mice. (c) T1D incidence in I-A^g7-WT/WT mice derived from intercrossing I-A^g7-PD/WT or I-A^g7KO/WT mice. ns P > 0.05, logrank Mantel-Cox test. (d) T1D incidence in I-A^g7-KO/KO and I-A^g7-WT/WT mice derived from intercrossing I-A^g7-KO/WT mice. (e–h) Cell surface expression of MHC molecules on APC subsets. (e,f) I-A^g7 and (g,h) H2-K^d expression level and average mean fluorescence intensity (MFI) of CD19⁺ B cells, CD11c⁺ XCR1^neg cDC2 and CD11c⁺ XCR1^pos cDC1 from I-A^g7-WT/WT (n = 5) and I-A^g7-PD/PD (n = 5) mice. (i,j) Representative hematoxylin and eosin staining of a grade 3 islet and grade 1 islet from the pancreas from I-A^{g7 WT/WT} and I-A^{g7 PD/WT} bearing mice, respectively. (k) Average frequency of islet infiltration severity at 12 weeks of age (n = 8) using a four scale grade: 0 - insulitis free, 1- peri-insulitis, 2 – moderate < 50% infiltrated, 3 – severe > 50% infiltration. (l) Quantification of Foxp3⁺ regulatory T cell subsets within the pancreatic infiltrate of I-A^{g7 WT/WT} (n = 24), I-A^{g7 KO/WT} (n = 10), I-A^{g7 PD/WT} (n = 25) or I-A^{g7 PD/PD} (n = 10) NOD mice. n = biologically independent animals. ns P > 0.05; * P < 0.05; ** P < 0.01 (one-way ANOVA with Tukey’s multiple comparisons test).