The role of T cells in beta cell damage in NOD mice and humans

The NOD mouse has been available to research community for approximately 15 years and in that time tremendous advances have been made in understanding the role of the immune system in development of Type 1A diabetes. It is clear that beta cell destruction is mediated primarily by T cells with both CD4+ and CD8+ T cells playing an important role. It should be kept in mind that development of diabetes in the NOD mouse differs from that in humans in several respects, including a marked sex bias in females and very high concordance (80-90% in NOD female mice) compared with the 30-50% observed in human identical twins. Nevertheless, the NOD mouse provides a very important model for understanding diabetes pathogenesis in humans. The data obtained thus far from investigation of human subjects are much less compelling with regard to a direct role for T cells in beta cell destruction than data from the NOD mouse. Nevertheless, it appears that T cells are involved and it is probably only a matter of time before advance in techniques will allow a definitive assessment of the participation of T cells in human type I diabetes.