A new method of thyroid allografts in mice was established. Thyroid follicles of C57BL/6J mice were isolated and treated with anti-Ia antibody plus complement in order to eliminate Ia-positive cells. The follicles were mixed with agarose and transplanted under the renal capsule of BALB/c mice. Acceptance of the grafts was verified by histological study 100 days after transplantation. Allografts treated with anti-Ia antibody plus complement were accepted. These findings indicate that Ia-positive cells play a crucial role in the rejection of mouse thyroid allografts, and that the deletion of Ia-positive cells permits allografts to be accepted. Our method presented here may be developed as a strategy for the treatment of patients with congenital or acquired hypothyroidism.
