Nuclear Medicine Technology and Other Health Applications Project Title: Lymphocytopoiesis and Transplantation Immunology 16. Technical Progress in FY 1973: (Cont'd) RX-01-03- (d) ECIB. Thoracic duct cells, labeled in vitro with tritiated thymidine to tag a fraction of the large cells, were infused intravenously. The total output of labeled and unlabeled lymphocytes in thoracic duct lymph and the concentration of labeled and unlabeled lymphocytes in the blood was monitored daily, during and following ECIB. The total output of labeled and unlabeled lymphocytes in thoracic duct lymph declined. Blood lymphocyte concentration showed similar changes. Cell size analysis in thoracic duct lymphocytes showed that small non-dividing lymphocytes and large dividing lymphocytes were decreased, To reduce costs to meet budgetary restrictions, a project on the influence of long term thymectomy on lymphocytopoiesis and transplantation immunology was terminated by killing 30 goats that had been followed for up to five years after thymectomy. ‘This project will not be reactivated until it is certain that adequate manpower will be available on a long-term basis. Three schedules of ECIB have been used to prepare goats for renal transplants. Randomly selected donors and recipients have been used. With the exception of ECIB-I, donor-recipient pairs checked for "closeness of match'’ with a one-way lymphocyte culture technique. ECIBeI consisted of irradiating 5-10 blood volumes per day for 10-15 days prior to transplantation with a high transit dose varying from 275-400 rads, This schedule had provided encouraging results when used as an adjunct with standard immunosuppression in preparing human beings for renal transplantation at the Rigshospitalet University of Copenhagen, Denmark, and at the Department of Surgery, University of Goteberg, Sweden. ECIB-I was used without any supportive chemical immunosuppressive therapy or donor-recipient matching. was induced. The results were disappointing and hemolysis ECIB-II shcedule was devised to reduce dose to red cells and time required for pre-transplant perparation. Fifteen to eighty blood volumes were irradiated each day for three to eight pre-transplant days, the transit dose ranging from 35-50 rads. Some animals retained kidney grafts for significantly longer periods. There was, in general, a good correlation between closeness of match obtained from the one way leukocyte culture and the length of allograft survival in the control and the sham-ECIB groups. In the group receiving ECIB, however, the longest survivor was very poorly matched with its donor. These Limd results suggest that the degree of histocompatibility may not be GM only factor determining the success of immunosuppression with EC LEME- The results of renal transplants are: (1) untreated recipients, 12 transplants 19 days mean survival (range 15-35 days); (2) ECIB-I, 8 transplants, 9 transplants, 18 day mean survival (range 14-24 days); 30 day mean survival (range 2-58 days); 13 transplants, 48 day mean survival (range 19-84 days); (See Continuation Sheet) 1119232 (3) ECIB-II, (4) ECIB-III, (5) Sham ECIB, RX-74