CD4 and diabetes mellitus: A major strength of the NOD model for human T1D compared to diabetes induced by chemical substances (STZ, alloxan, dithizone) (38, 40, 41) is the similarity to human T1D, as the NOD mice develop pancreatic islet β-cell autoantibodies (42) and their islets are infiltrated with CD4+ and CD8+ lymphocytes (40).