| Abstract: | Treatment of recipient mice with donor bone marrow cells and anti-lymphocyte serum (ALS) results in extensive skin graft prolongation beyond that achieved in animals given only ALS. In this study, B6AF1 recipient mice were grafted with C3H/He skin on day 0, treated with ALS on days -1 and +2 and infused on day +7 with donor strain (C3H/He) bone marrow cells. Extensive graft prolongation was achieved either with 25 X 10(6) whole bone marrow cells or with 1 X 10(6) lymphoid-like cells derived from donor marrow that sediment at a rate of 3 mm/hr in a 2 to 4% Ficoll gradient at unit gravity. These allograft-prolonging lymphoid-like cells appear not to be CFUs cells, have suppressive activity in in vitro MLC assays, and contain both nylon wool adherent and non-adherent cells. These studies thus show that allograft promoting cells can be isolated from bone marrow utilizing Ficoll gradients. Functional studies suggest that 3 mm/hr sedimenting donor bone marrow suppressor cells may be involved in the induction of allograft prolongation. |
