Nuclear Medicine Technoiogy and Qther Health Applications Project Title: 16. Lymphocytopoiesis and Transplantation Immunology Technical Progress in FY 1973: (Cont'd) RX-01-03-(d) 10 transplants, 25 day mean survival (range 13-34 days). In October 1972 the renal transplants were temporarily discontinued due to budgetary restrictions. 17. Expected Results in FY 1974: Analysis of autoradiographs in thymocyte migration, life span and lymphocyte recirculation will be completed, data analyzed and submitted for publication. Size distribution data collected over 7 years on lymphocytes during ECIB will be analyzed. Studies on role of the adrenal in ECIB-L induced lymphopenia will commence using adrenalectomized calves maintained on level steroid intake. Thymic cell migration studies will continue with efforts to determine the life span of thymic migrants in the peripheral lymphoid tissues and whether the lymphocytes known to migrate into the lumen of the gut are B or T cells. If the apparent stimulatory influence of lymphopenia upon bone marrow lymphopoiesis is confirmed, this apparent breakthrough in the study of Lymphopoiesis will be exploited with studies focused on the possible thymic bone marrow feedback loop. Lymphoid cell mixtures will be grown in diffusion chambers for . evaluation of the role of T cells in antigeneic recognition, their interaction with B cells, and the bodies. identity of cells that produce anti- Studies on ECIB in renal transplantation in goats will be reactivated if the Large Animal Facility can be operated seven days a week. Studies will include: combination of ECIB and ECIL to further elucidate the mechanism of allograft rejection and to further prolong the survival of renal transplants; combination of ECIB and immunosuppressive chemicals to determine the efficiency of these procedures for eventual application in human patients; "matching" of recipient-donor pairs in combination with mixed breeding; and in vitro studies of the influence of "killer" cells on kidney cells. Studies on the regional. perfusion of various lymphoid organs with wtive isotopes have been limited by budgetary problems. These and @ are designed to enable better understanding of the patterns itude of lymphocyte traffic under more or less physiologic conditions. This kind of information is essential to understand the overall phenomenon of lymphocytopoiesis. Thymus perfusion studies will be extended to bone marrow, spleen and lymph nodes. After present data are analyzed, regional perfusion of lymphoid organs with tritiated thy- midine will be undertaken with emphasis on bone marrow perfusion. (See Continuation Sheer) 1119233 RX-75