Non-cohoused NOD.NOD2−/− mice exhibit reduced T1D incidence and a decrease in CD4+ IFN-γ+/CD8+ IFN-γ+ (Th1/Tc1) and CD4+ IL-17+/CD8+ IL-17+ (Th17/Tc17) T cells in PLNs, indicating that NOD2 activation regulates T1D development by altering the composition of gut microbiota and by modulating the adaptive immune response (86). Here, CD4 is linked to type 1 diabetes mellitus.