Islet allograft, islet xenograft, and skin allograft survival in CD8+ T lymphocyte-deficient mice. Discussion

Despite extensive study, the immunologic mechanisms mediating allograft rejection have not been completely defined. In the current study, we evaluated the T cell subsets important in islet allograft, skin allograft, and islet xenograft rejection using a genetically engineered line of mice deficient in β 2 -microglobulin expression. Because these mice lack cell surface MHC class I expression, they are deficient in T cells of the CD8 subset (class I-restricted cytotoxic T cells). Pancreatic islet allografts transplanted to CD8 + T cell-deficient recipients showed prolonged survival compared with controls. No prolongation was observed in the survival of pancreatic islet xenografts or in the survival of skin allografts transplanted to the CD8 + T cell-deficient hosts