Enhancement of heart allograft survival across H-2D differences

The use of split heart allografts in the study of immunological enhancement was evaluated. The study revealed that, in contrast to the results with skin grafts, it is possible to obtain exceptional increases in the survival of heart grafts across differences at the H-2D end of the H-2 complex. The factors affecting graft survival were the age of the heart tissue used in grafting, the haplotype of the donor and host, the regimen of injections of antibody, and the immune reagent used. The data suggest that a difference exists in the mechanism by which anti-Ia and anti-H-2D antibodies mediate their enhancing effect.