INS and diabetes mellitus: Despite the high degree of homology in the B:9-23 epitope and cross-reactivity of T cells for the Ins B: 9-23 epitope, a divergent immune response was observed when NOD mice were immunized with either Ins1 B:9-23 or Ins2 B:9-23 peptides, with Ins2 peptide conferring protection from diabetes onset, whereas Ins1 peptide did not prevent disease (13, 14).