Abnormal development of the thymus in "nude" mice.

Nude mice bearing grafts of normal thymus reject skin grafts and have low, but higher than usual, lymphocyte counts. Nude bone marrow can successfully repopulate the thymus and thymus-derived areas of lethelly irradiated recipient mice. Attempts to reconstitute nude mice with normal fetal liver failed. The so-called thymic rudiment of nude mice when grafted to normal mice did not develop thymocytes. These experiments show that nude mice suffer from a defect of the epithelial portion of the thymus rather than of the precursors of thymocytes.