Skin allograft and xenograft rejection in the snapping turtle, Chelydra serpentina

The immune response of the snapping turtle, Chelydra serpentina , to skin allografts and xenografts at several environmental temperatures was studied. Xenografts were supplied by the painted turtle, Chrysemys picta , and the Blanding turtle, Emys blandingii. Gross and microscopic manifestations of rejection were observed. Beginning of graft death and total graft death marked two survival end points. The first of these events was used in statistical comparisons of mean survival times of grafts of the various series, which included a total of 107 host animals involving 74 allografts and 76 xenografts. Skin autografts survived through the periods of observation with no morphological evidence of incompatibility. Using gross and histological survival end points, which indicated the beginning of graft death, first‐set allografts were rejected in about 40 days; second‐set in about 21 days, at 25 ± 1°C. Allografts from young snappers survived slightly longer. Xenografts from both donor species were rejected after nearly the same survival times. First‐set xenografts were rejected in about 24 days; second‐set xenografts in about 16 days, at 25 ± 1°C. Painted turtle skin xenografts on snappers which had previously received painted turtle tissue in transplantation between embryos, survived significantly longer, about 36 days. There was no morphological evidence of rejection of first‐set allografts of xenografts for the observation period of 100 days, at 10 ± 1°C. Allografted snappers that were transferred to 25 ± 1°C, rejected the grafts about 30 days after the transfer. First‐set allografts were rejected much faster at 33 ± 1°C, in about 24 days, as were first‐set xenografts, in about 17 days.