In contrast, only 33.3% of NOD/SCID mice receiving splenocytes from CTB-Ins-GAD or CTB-GAD-Ins developed diabetes, while 66.7% of NOD/SCID mice receiving splenocytes from mice fed CTB-GAD developed diabetes (33.3% vs 66.7%, p<0.05; 33.3% vs 100%, p<0.01; 66.7% vs 100%, p<0.05), respectively, at 18 weeks after transfer These results indicated that CTB-Ins-GAD has a synergistic effect in adoptive transfer by splenocytes from antigen-fed mice, and that oral administration of CTB-Ins-GAD could induce a greater number of regulatory CD4+ T cells and suppress diabetogenic T cells. Here, GAD1 is linked to diabetes mellitus.