Abstract
The genetic differences in the competence of the donor to affect splenomegaly in GVH reactions were studied. The degree of splenomegaly induced by N strain donors was higher than that induced by C strain donors in White Rock embryo hosts which have quite different alleles at the B blood group system from both donor strains. F1 and F2 donors induced splenomegaly of a similar degree to that induced by C strain donors. NBc donors induced larger spleens than did CBc donors. Similar tendencies were observed when New Hampshire embryos were used as hosts. These results indicate that there are genetic differences in the competence of donors of these two strains.
Association of the B locus alleles of the donors with the degree of splenomegaly was found. The effect of the BA allele was generally stronger than the BG allele and the BI allele was of intermediate effect. Similar effects were also observed when blood-grouped White Leghorn embryos were used as hosts. It is suggested that a considerable part of the strain differences found would be brought about by the differences between alleles at the B locus in the donors.
