The maturation of the capacity to reject skin allografts and xenografts in the snapping turtle, Chelydra serpentina

Skin allografts and Blanding skin xenografts were transplanted to young snapping turtles ranging in age from newly‐hatched to six months. In this study, involving 88 skin allografts and xenografts, it was shown that the snapping turtle matures immunologically in its capacity to reject grafts several months after hatching. It takes newly‐hatched turtles over 90 days to reject skin allografts and xenografts. The survival times are nearly half that when the animals are only one month of age. Mean survival times then drop a few days with each month of age. By four to six months, snapping turtles reject skin allografts and xenografts at about the same rate as do adult snappers. Skin xenografts were rejected faster than allografts at every age after the newly‐hatched series. There were some cases of very extended sibling skin allograft survival during the early months posthatching. A later series involving older animals showed that sibling allografts were rejected at nearly the same rate as non‐sibling allografts.