Heart and Kidney Transplantation from Segregating Hybrid to Parental Rats

We have plans for testing the one locus hypothesis of organ transplantation in a number of strain combinations, and will present here the data obtained from the two first combinations tested. The technique of kidney grafting follows with minor modifications the one used earlier in this laboratory (Sakai, Simonsen & Jensen 1969). The technique of heart grafting is as described by Pettirossi et al. (1968) whereby the heart is joined to the recipient's aorta and inferior v. cava as an accessory abdominal heart. The test consists in a comparison of the fate of kidney, heart, and skin grafts from individual donors belonging to segregating hybrid populations (F2 or back-cross) to different recipients of one of the parental strains. The donors are typed for the presence or absence of the foreign Ag-B allele prior to grafting, by serotyping and by MLC. As illustrated by Figure 1 there was complete agreement between serotyping and MLC, as shown by the fact that stimulation of AS cells always and only occurred with cells from hybrids which serotyping had shown to contain the AS2 haemagglutinogen presumed to be determined by Ag-B. The survival data for the three kinds of grafts are given in Tables I and II. Table I contains the data for the strain combination AS-AS2 with AS rats as recipients. This is the combination we began with, and is so far the one with the most extensive data. As we shall soon see it was not the most fortunate choice for a beginning. Group I demonstrates that the straightforward interstrain grafting from AS2 to AS leads to acute rejection in 10—12 days of both skin and kidney, whereas one of the grafted hearts is still beating after 106 days. The simple prediction from the one locus hypothesis (disregarding for the moment the possible effect of gene dosage) is that F2 and BC donors which