title: Demonstration of cells possessing tolerance-inducing activity in Xenopus laevis rendered tolerant perimetamorphically.
abstract: J-strain (JJ) Xenopus laevis is easily made tolerant to semixenogeneic (X laevis x X borealis: JB) adult skin grafted onto immunologically competent larvae at stages 53-54. If the larvae are thymectomized shortly before skin grafting (late Txd), tolerance will never be induced. This suggests that suppression of the immune response to JB skin is mediated by a population of thymus-derived cells. In an attempt to confirm the presence of these cells, the spleen and tolerated JB skin were tested for their tolerance-inducing activity, by grafting either spleen or skin and a new JB skin piece simultaneously to late Txd JJ larva (secondary host). The results clearly indicated that both spleen and skin possessed the ability to induce tolerance. The injection of 1 x 10(5) splenocytes resulted in induction of tolerance in more than 80% of secondary hosts, and the rate of tolerance induction increased in relation to the injected cell number. Furthermore, tolerance was induced in about 90% of the animals by injecting as few as 100 cells isolated from the tolerated skin. Immunohistochemical observation of grafted skin showed that many host-derived T cells were distributed around the epidermal basal lamina. These results indicate that the cells with suppressive activity are a population of T cells that have differentiated in metamorphosing thymuses and have been released peripherally.
authors.affiliation: Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Ono
authors.forename: S
authors.initials: S
authors.lastname: Tochinai
mesh_terms: D000818:Animals; D006084:Graft Rejection / Q000276:immunology; D006085:Graft Survival / Q000276:immunology; D007108:Immune Tolerance; D007814:Larva / Q000276:immunology; D016038:Skin Transplantation / Q000276:immunology*; D013154:Spleen / Q000276:immunology; D013934:Thymectomy; D014183:Transplantation, Heterologous; D014982:Xenopus laevis / Q000276:immunology* / Q000601:surgery