Immunological reactivity of B mice reconstituted with various numbers of syngeneic bone marrow cells.

Adult thymectomized mice were sublethally irradiated and reconstituted with various doses of syngeneic bone marrow. Immunological reactivity was assessed by allogeneic skin grafting at various intervals after reconstitution. It was found that reconstitution with high doses (1 X 10(7), 2 X 10(7)) of bone marrow was associated with an ability to reject allogeneic skin grafts and that this reactivity increased with time. Following rejection of a first skin graft, second grafts were rejected in an accelerated manner. These mice had measurable levels of Thy 1.2 positive cells in the spleen. In contrast, low-dose bone marrow reconstitution (1 X 10(6), 2 X10(6)) produced mice which did not reject either first or second allogeneic skin grafts, and such mice had at most only very low levels of Thy 1.2 positive cells in their spleens.