Abstract
Skin graft were exchanged between inbred strain mice and their Fl hybrids. Then, the relationship between survival time of those skin grafts and mitotic metaphases in the recipient mice after skin grafting wre investigated. Those mice such as C3H/He, AKR and CBA with the identical H-2 histocompatible factors showed further elongation of skin survival time as compared with the H-2 histocompatible strain. Although the difference in H-2 seems to be greatly effective on the rejection of grafts, its extent is variable.
After parabiosing C3H/He and the same sexual DDD, parabiotic union was spontaneously separated on 8.3 postoperative day or one partner died of parabiotic disease. Parabiotic union between C3H/He and its F1 hybrid continued for 11.2 days on an average and that between DDD and F1 was durable for 57.3 days (mean)
Although the grafts from parent to F1 hybrid survived for a long time, but the bone marrow cells 10 days after skin grafting showed a remarkable declination of mitotic metaphases.
These experimental results suggest that the existence of equilibration between survival time of skin homografts and duration of parabiotic union. In genetically close relationship such as parent and F1 hybrid, a barrier of weak histocompatibility can be suppressed by 60Co irradiation. It was suggested that an immune response should be inhibited by any means even in genetically close combination.
