Liver-induced immunosuppression of allograft immunity in urodele amphibians

In different newt hosts, control allogeneic skin grafts and s.c. liver fragment implants were chronically rejected at similar times (4-10 weeks posttransplantation). However, when liver-implanted newts were challenged with test skin grafts from the original donors, survival of both skin and liver was often dramatically prolonged. Whereas, first- and accelerated second-set control skin graft median survival times were 42.5 and 21.5 days, median survival times for test grafts transplanted 1, 3, 6, or 9 weeks after liver implantation were 60.5, 79.1, 37.5, and 49.0 days, respectively. The 3-week interval between the two transplants was associated with the highest incidence (29%) of test skin graft survival beyond the upper range limits of control first-set skin graft survival (>150 days). In each experimental interval group, some newts were effectively sensitized by liver implants since they rejected their subsequent test skin grafts below the lower range limit of control first-set skin grafts (