Bone marrow transplantation with t–cell–depleted grafts: I. Reconstitution of immunohemopoietic functions in lethally irradiated mice transplanted with unseparated or T-cell-depleted syngeneic bone marrow grafts

The potential role of donor's mature t lymphocytes on the recovery of various immunological functions and hematopoiesis was investigated in lethally irradiated BALB/c mice by studying reconstitution with normal, as compared with T-cell-depleted, syngeneic marrow grafts. Recovery of total, as well as mononuclear, peripheral white blood cell counts, platelets, hemoglobin levels, proportion of Thy 1.2⁺ cells, responses to concanavalin a, phytohemagglutinin and lipopolysac-charide, mixed lymphocyte response, cell-mediated lympholysis response, anti-SRBC agglutinins and natural killer activity were basically similar in recipients of unnmanipulated (as compared with t cell depleted) syngeneic marrow greafts. The data suggest that in a syngeneic murine bone mrrow transplantation setting, mature donor T lymphocytes do not seem to play a major role in immunohemopoiesis. Normal T cell number and T-cell-dependent immune functioncan be readily regenerated out of the stem cell reservoir of adult donors following transplantation into lethally ablated recipients.