Human immune system development and rejection of human islet allografts in spontaneously diabetic NOD-Rag1null IL2rgammanull Ins2Akita mice.

OBJECTIVE

To create an immunodeficient mouse model that spontaneously develops hyperglycemia to serve as a diabetic host for human islets and stem cell-derived beta-cells in the absence or presence of a functional human immune system.

RESEARCH DESIGN AND METHODS

We backcrossed the Ins2(Akita) mutation onto the NOD-Rag1(null) IL2rgamma(null) strain and determined 1) the spontaneous development of hyperglycemia, 2) the ability of human islets, mouse islets, and dissociated mouse islet cells to restore euglycemia, 3) the generation of a human immune system following engraftment of human hematopoietic stem cells, and 4) the ability of the humanized mice to reject human islet allografts.

RESULTS

We confirmed the defects in innate and adaptive immunity and the spontaneous development of hyperglycemia conferred by the IL2rgamma(null), Rag1(null), and Ins2(Akita) genes in NOD-Rag1(null) IL2rgamma(null) Ins2(Akita) (NRG-Akita) mice. Mouse and human islets restored NRG-Akita mice to normoglycemia. Insulin-positive cells in dissociated mouse islets, required to restore euglycemia in chemically diabetic NOD-scid IL2rgamma(null) and spontaneously diabetic NRG-Akita mice, were quantified following transplantation via the intrapancreatic and subrenal routes. Engraftment of human hematopoietic stem cells in newborn NRG-Akita and NRG mice resulted in equivalent human immune system development in a normoglycemic or chronically hyperglycemic environment, with >50% of engrafted NRG-Akita mice capable of rejecting human islet allografts.

CONCLUSIONS

NRG-Akita mice provide a model system for validation of the function of human islets and human adult stem cell, embryonic stem cell, or induced pluripotent stem cell-derived beta-cells in the absence or presence of an alloreactive human immune system.