Induction of long-term tolerance in the quokka (Setonix brachyurus) by thymus and skin allografts into early pouch young.

Intact quokkas (Setonix brachyurus) were grafted with thymus and skin as neonates. Fifty seven percent of primary thymus grafts persisted when donors were less than 32 days of age, compared with only 20% when the dornors were juveniles. This suggested that neonatal tissue was more readily accepted than tissue from adult animals. When the recipients had left the pouch, induced tolerance was tested by grafting thymus and skin from the original donors. Second thymus grafts were generally unsuccessful; however, second skin grafts were accepted and remained intact over the three-year period of observation, provided that the hosts were less than about 40 days of age at the time the first graft were placed.