Amphibian Transplantation Reactions: A Review

SYNOPSIS. Productive research with three amphibian orders hasyielded numerous insightsinto the phylogeny of lymphoid systems,immunoglobulin production and structure, and transplantationalloantigens and the immune responses they elicit. In this reviewof amphibian transplantation biology, evolutionary significancehas been placed on the differential survival rates of first-and second-set grafts in normal and immunosuppressed urodeles,apodans, and anurans. In the absence of a major histocompatibilitycomplex, apodans and urodeles typically reject skin allograftsand xenografts chronically; median survival times range from30 to 55 days. Manyorgans (heart, gonads, pituitaries, eyes)transplanted across the weaker histocompatibility barriers insalamanders survive for longer than a year. Two Diemictylussubspecies, however, reject skin grafts (but not heart grafts)somewhat more vigorously in a subacute fashion. Primitive anuranssuch as Xenopus also reject skin grafts in this fashion. Onlyrepresentatives of the phylogenetically advanced Ranidae respondto skin and other organ allografts in an acute fashion comparableto the mammalian response elicited by strong histocompatibilityantigens.