Effect of the treatment of parental cells in vitro with anti-T antibody on bone marrow transplantation in F1 hybrid mice.

: Anti-T antibody was obtained from xenogeneic antithymocyte serum by adsorption and elution with brain immunosorbent. Bone marrow and spleen cells from the parental A strain were treated in vitro with anti-T antibody and complement or with the original ATS and complement. So treated cells were assayed for the ability to induce a local and a total GVH reaction in (A X C57BL)F1 hybrid mice, to prolong the survival of lethally irradiated, identical F1 hybrid mice and to form haemopoietic colonies in spleens of the syngeneic irradiated recipients. The local GVH reaction induced by anti-T antibody- and ATS-treated spleen cells was somewhat lower. Administration of a mixture of spleen and bone marrow cells treated with anti-T antibody prolonged the survival of lethally irradiated recipients but did not prevent the consequences of late GVH reaction. The colony-forming activity of bone marrow cells treated with anti-T antibody was not reduced in most experiments. It can be concluded that the treatment of cells from mouse haemopoietic organs with anti-T antibody and complement damages mature T lymphocytes and in this way reduces the ability to induce GVH reaction, but does not damage T lymphocyte precursors and haemopoietic stem cells.