Suppression of allogeneic lymphomas in spleens of irradiated mice: importance of the D end of the H-2 complex.

Dispersed lymphoma cells were transplanted into heavily irradiated mice of a series of congenic resistant strains. Newly synthesized deoxyribonucleic acid was subsequently measured to estimate tumor cell proliferation in spleen and liver. Despite host irradiation, growth of lymphoma cells was suppressed 4 to 7 days after transplantation in the spleen of mice of certain allogeneic strains, but it was barely affected in the liver. The genetic differences resulting in "localized" resistance were mapped in the D region of the H-2 complex. Differences at other regions, including those most important for transplantation resistance in nonirradiated mice (K, I), were inconsequential for lymphoma growth in irradiated hosts. There was a striking resemblance with hemopoietic histoincompatibility, i.e., the rejection of foreign bone marrow grafts by irradiated mice, suggesting that the products of strong Hh gene(s) were expressed in the lymphoma cells.