The murine diabetogenic class II histocompatibility molecule I-Ag7: structural and functional properties and specificity of peptide selection.

The onset of type 1 diabetes mellitus (T1DM) is directly linked to the expression of class II MHC molecules. The NOD mouse, which is an excellent animal model for the human disease, expresses the I-Ag7 molecule that shares many features with the human diabetogenic class II MHC alleles. In this review, the structural, biochemical, and biological properties of the I-Ag7 molecules and how they relate to onset of diabetes is discussed. In particular, the focus is on the unique properties of peptide selection by I-Ag7 that reveal the preferred binding motif of diabetogenic MHC molecules and its role in display of peptides derived from islet beta cells.