ABSTRACT
Grafting of tissues or organs between genetically unrelated individuals is usually followed by rejection of the grafted tissue or organ. On the other hand, if tissues or organs are transplanted between genetically identical individuals, rejection does not take place. Development of inbred strains of mice was a prerequisite to designing experiments to advance our understanding of the factors controlling graft rejection or acceptance. Inbred strains are obtained after 20 or more generations of brother/sister mating, and all individuals of a strain are virtually identical genetically. Skin-grafting experiments using inbred mice have shown that ability to accept or reject a graft is under genetic control, and that it is subject to the general immunological rules of specificity and memory. When skin was grafted among animals of the same inbred strain, no rejection was observed. When grafting involved mice of different strains, the recipients rejected the graft; the speed and intensity of the rejection reaction were clearly dependent on the degree of genetic relatedness between the strains used in the experiment.
