Behavior and fate of transplanted tooth buds: III. A simultaneous change in host and graft after allogeneic transplantation

This investigation tested the hypothesis that tooth bud allografts once established in the host become less vulnerable to subsequent immunological attack. The first molar buds of 10-day-old rats were allografted to mature animals in different combinations. (1) Buds allografted alone showed an initial acceptance rate of 58% at 10 weeks after transplantation, which decreased to 32% at 20 weeks. (2) Buds that were grafted simultaneously with spleen were invariably destroyed, while (3) buds that were grafted 4 or 10 weeks prior to the addition of spleen showed improved acceptance rates (16-21%). It was concluded that gradual sensitization of the host occurred simultaneously with gradual “adaptation” of the graft. It is, therefore, suggested that, under the present experimental conditions, the fate of the graft is determined by the speed and intensity of these two processes and the relative preponderance of one over the other.