Induction of tolerance to parental marrow grafts in F sub(1) hybrid mice. Evidence for recognition of self-antigens

Lethally irradiated (C57BL/6 x C3H)F sub(1) mice are able to acutely reject parental C57BL/6 but not C3H marrow grafts, a phenomenon called hybrid resistance (HR). In attempts to inactivate this rejection mechanism we found that parental spleen cells activated with LPS are very potent in inducing tolerance to a subsequent C57BL/6 marrow graft. Tolerance is likely due to elimination of effector cells responsible for graft rejection as adoptive transfer of spleen cells from normal into tolerized mice reconstitutes responsiveness. Evidence is presented that the Ag on LPS-activated spleen cells responsible for induction of unresponsiveness are expressed on both C57BL/6 and (C57BL/6 x C3H)F sub(1) cells.