Transplantation of Islet Cells Across Major Histocompatibility Barriers After Total Lymphoid Irradiation and Infusion of Allogeneic Bone Marrow Cells

Diabetic Lewis rats (AgB1/L) were evaluated as recipients of allogeneic Wistar-Furth (AgB2/2) isolated adult islets without the use of standard recipient immunosuppression. One group was treated with fractionated total lymphoid irradiation (TLI) and Wistar-Furth bone marrow cell reconstitution to proven chimerism prior to islet transplantation. This group returned to a prediabetic state following Wistar-Furth islet transplantation without any evidence of rejection for 100 days posttranspiant. A second group of Lewis rats received only TLI without bone marrow treatment. They gave a varying result following islet transplantation with one recipient showing evidence of prolonged islet survival. A third chimeric control group did not receive isolated islets and did not alter their diabetic state. A fourth group was not given TL6 nor donor bone marrow cells and uniformly rejected their allogeneic islets by 7 days. Thus, allogeneic adult islets will survive across major rat histocompatabiiity barriers using TLS and donor bone marrow chimerism as the only form of immunosuppression.