Cytotoxic transplantation immunity in the sponge Toxadocia violacea

The Hawaiian sponge, Toxadocia violacea, exhibited discriminating transplantation immunity in an extensive series of allogeneic and xenogeneic parabioses. Cytotoxic alloincompatibility occurred without exception, but with differing degrees of severity. The allorejection reactions developed more rapidly than has been observed in any other animal species. An intense tissue-bridging reaction in allogeneic contact zones preceded acute soft tissue destruction; the cytotoxic reactivity was usually restricted to the immediate zone of direct contact. The median reaction times were closely temperature-dependent and much accelerated at higher temperature. Specific, short-term alloimmune memory was revealed by second-set and third-party graftings. Extensive allogeneic polymorphism was evident from the invariable rejection observed among more than 140 different pairings. Xenograft reactions between Toxadocia violacea and Callyspongia diffusa were characterized by acute cytotoxicity, immune memory, and a qualitative change in secondary versus primary responses.