Thymus transplantation and disease prevention in the diabetes-prone Bio-Breeding rat.

Bio-Breeding rat T lymphocytes proliferate poorly in response to alloantigen. Transplantation of Bio-Breeding rats with fetal thymus tissue from diabetes resistant rats leads to an improvement in the T cell proliferative response, but only if the thymus contains bone marrow-derived, radiation-resistant thymic antigen presenting cells of the diabetes-resistant phenotype. The current study provides evidence that thymus transplantation leading to the restoration of Bio-Breeding T cell proliferative function can also significantly reduce the incidence of insulitis and prevent the development of diabetes. It appears that a defect in the bone marrow-derived thymic APC population contributes to an abnormal maturation of Bio-Breeding T lymphocytes which in turn predisposes animals to insulitis and diabetic disease.