INS and type 1 diabetes mellitus: Studies by Krishnamurthy et al. further corroborated the hypothesis that insulin is the initiating Ag in the T1D of the NOD mouse, because mice rendered tolerant to insulin by transgenic overexpression of insulin 2 in Ag-presenting cells do not develop the immunodominant IGRP206–214-specific responses and are protected from T1D [26].