1. Though thymus-fed salamander larvae often metamorphose normally, thymus feeding sometimes retards and in rare cases inhibits metamorphosis completely. 2. The addition of normal food to a thymus diet abolishes the inhibitory effect of the thymus. 3. Addition of a small quantity of iodothyrin leads rapidly to precocious metamorphosis of thymus-fed larvae. 4. The inhibitory effect of the thymus...

Thymus function is thought to depend on a steady supply of T cell progenitors from the bone marrow. The notion that the thymus lacks progenitors with self-renewal capacity is based on thymus transplantation experiments in which host-derived thymocytes replaced thymus-resident cells within 4 wk. Thymus grafting into T cell-deficient mice resulted in a wave of T cell export from the thymus, follo...

Lymphopoiesis was studied in 3-month-old normal C57Bl mice and in 3-month-old C57Bl mice carrying from 12 to 48 C57Bl thymus grafts using tritiated thymidine labeling. Thymus graft lymphopoiesis was found to be identical with that of normal thymus tissue and the presence of thymus grafts was found to have no influence on host thymus lymphopoiesis. No evidence was found that the massive amounts ...

Introduction. ...................................... Lymphopoiesis. ................. : ................... Lymphocyte compartments. ........................ Origin of thymus lymphocytes. ..................... Proliferation of thymus lymphocytes. ................ Fate of thymus lymphocytes. ....................... Regulation of thymus lymphopoiesis ................. Evidence linking some lympho...

Antibodies to purified calf thymus Fl, and to chromatographically purified subfractions of calf thymus Fl histones were induced by immunization of rabbits with histone-RNA complexes. Complement fixation studies with these antibodies demonstrated structural differences between the subfractions in one organ and between those of different organs and species. The anti-F1 sera showed varying reactiv...