Figure 4

Islets from Idd9 congenic mice are intrinsically resistant to cytokine and CD8 T cell-mediated autoimmune destruction. Islets isolated from 5 week old Idd9 congenic and NOD donors were transplanted under the kidney capsule of NODScid recipients. After allowing 7 days for the grafts to revascularize, splenocytes from 8.3NODScid mice (30 million cells) were adoptively transferred into graft recipients. Control mice did not receive splenocytes. Five days later, graft destruction was analyzed by H&E staining of graft sections, as shown in (A) (i-iv). Scoring of graft destruction (B) was determined by anti-glucagon staining (A) (v-vi) as described in the methods. NOD grafts (n = 4), NOD control grafts (n = 2), Idd9 congenic grafts (n = 3) and Idd9 control grafts (n = 2) were assessed, and a total of 24, 11, 26 and 32 islets scored, respectively, for each group. Graph shows average % healthy islets in each graft +/- SEM. Results representative of 3 independent experiments. (C) Confocal live/dead viability staining of islets from 5 week old Idd9 congenic and NOD mice treated with, or without, TNF (2,000 U/ml) and IFNγ (1,000 U/ml) for 6 days. Live cells stain green, and the nuclei of dead cells stain red. For each assay, 7–9 islets (250–500 cells) were analyzed and the average % dead cells per field +/- SEM is shown in (D). Results representative of 3 independent experiments.