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 lipopolysaccharide, mixed lymphocyte response, cell-mediated lympholysis response, anti-SRBC agglutinins and natural killer activity were basically similar in recipients of unmanipulated (as compared with T cell depleted) syngeneic marrow grafts. The data suggest that in a syngeneic murine bone marrow 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 function can be readily regenerated out of the stem cell reservoir of adult donors following transplantation into lethally ablated recipients.