Peripherin: an islet antigen that is cross-reactive with nonobese diabetic mouse class II gene products.

The nonobese diabetic (NOD) mouse, in which major histocompatibility complex genes may be involved in the susceptibility to diabetes, has been developed as a model of autoimmune diabetes. The NOD mouse expresses I-A-encoded class II major histocompatibility complex antigens, which differ from those of other mouse haplotypes by the presence of a serine at position 57 of the A beta chain. Identifying islet autoantigens may help elucidate the role of class II antigens in the activation of autoreactive T cells and, thus, in the development of diabetes. We have detected autoantibodies directed against a 58-kDa islet cell antigen in NOD mice but not in other strains, including lupus-prone mice. Apart from insulin-secreting cells, the 58-kDa antigen was only found to be expressed by neuroblastoma cells and was identified as peripherin, an intermediate filament protein previously characterized in well-defined neuronal populations. This autoantigen cross-reacted with I-Anod class II antigens, suggesting that it may contribute to defective self-tolerance of islet beta cells in the NOD mouse.