Reversal of diabetes by allogenic islet transplantation without immunosuppression.

Streptozotocin-induced diabetes is temporarily reversed following the allo-transplantation of BALB/c (H-2d) islet tissue to normal CBA (H-2k) recipients, but by 2-4 week post-transplantation these animals return to their initial diabetic condition. Organ culture of allogeneic islet tissue in 95% O2 and 5% CO2 for 7 days prior to transplantation reduces the immunogenicity of the tissue, and cultured allografts give prolonged (greater than 110 days) reversal of diabetes in normal allogeneic recipients. The non-fasting blood sugar level remains in or very close to the normal range, urine glucose output is one to two orders of magnitude less than that of diabetic control animals and allografted animals regain their pre-morbid body weight within 60 days of transplantation. Surgical removal of the allograft results in a rapid return of the animal to the initial diabetic condition.