Phylogeny of functional humoral transplantation immunity: comparative studies in amphibians and rodents.

Remarkably comparable observations from parallel experiments in salamanders and mice utilizing three related model systems (implant-induced immunomanipulation; passive transfer; and putative B cell suppression) argue directly that functional humoral transplantation immunity is highly developed at the phylogenetic level of Amphibia and that it plays a major role in regulating graft survival in these species (Fig. 4). Although it is still conjectural whether such humoral immunity and weak H-antigens evolved concurrently, the argument that enhancing atibodies evolved exclusively in viviparous species to protect the fetus from potential rejection by the maternal immune system no longer seems tenable (1).