Cultured thyroid allografts induce a state of partial tolerance in adult recipient mice

Thyroid allografts (BALB/c) prepared for transplantation by cyclophosphamide pretreatment of the donor, followed by organ culture of donor tissues for 3 weeks in a gas phase of 95% O2-5% CO2 function in normal CBA recipient mice for greater than or equal to 350 days. Up to 100 days post-transplantation, the tissue can be rejected by challenge of the recipient with 10(5) BALB/c peritoneal cells. After prolonged residence in the recipient (greater than 100, less than or equal to 350 days), only a proportion of allografts are rejected when the recipient is challenged with 10(5) followed by 10(6) peritoneal cells of donor origin. Recipients of long-term allografts are partially tolerant of BALB/c tissues. They are hyporesponsive to in vivo challenge with BALB/c spleen cells. However, lymph node cells from these animals respond essentially normally to stimulation with BALB/c spleen cells in vitro. Tolerant recipients will accept a second uncultured BALB/c allograft after a transitory rejection crisis. This crisis is not observed in the primary allograft.