Modulation of the antigraft response by preimmunization. Lack of correlation between regulatory events and graft...

Using two H-2 congeneic mouse strain combinations, the effect of donor specific i.v. preimmunizations with allogeneic spleen cells was studied. Parameters analyzed were survival time of the subsequent skin graft, graft-induced delayed-type hypersensitivity (DTH) reactions, and humoral immune responses evoked by immunization and grafting. Depending on the dose of allogeneic cells used for preimmunization, a suppression of the DTH response was observed, commonly accompanied by a similarly dose-dependent antibody formation that was inversely related to the DTH response. Neither DTH reactivity nor the antibody response were correlated in this system with the survival time of the skin graft. The only modulation of the survival time to be observed was an accelerated rejection of the graft caused by nonirradiated, as compared with irradiated, donor spleen cells. The data are discussed with regard to the clinically observed effect of blood transfusions on the survival of renal transplants and the relationship between DTH and graft rejection.