CD4 and diabetes mellitus: We made similar observations for conventional CD4+ T effector cells (Supplementary Figure S5), but anti-CD4 mAb (GK1.5) administration into cohorts of Treg cell-depleted NOD.DEREG mice (n = 10) did not appreciably interfere with the manifestation of overt diabetes, whereas anti-CD8α mAb (53.6.72) administration reduced the diabetes incidence to 10%, as compared to 50% in untreated and 60% in anti-CD4 mAb-treated mice (data not shown).