Skin and Tumor Grafting in Coisogenic Resistant Lines of Mice and Their Hybrids2

Abstract

Some of G. D. Snell's (1) isogenic resistant mouse strains and their hybrids have been tested by exchanging skin and tumor grafts. These strains have been developed with the purpose of fixing a one-histocompatibility-gene difference on a common coisogenic background. The lines used in the present study had a strain A background and differed with regard to the histocompatibility-2 locus. The results of tumor transplantation tests were in good agreement with the expected one-gene difference (75% takes in F₂ and 50% in backcross hybrids), and no additional histocompatibility differences could be detected by grafting into preimmunized hosts. In contrast, skin grafts revealed the existence of numerous other histocompatibility differences, involving not less and probably more than 10 loci. In addition, evidence was obtained for the existence of residual heterozygosis within the IR sublines, influencing the fate of skin but not of tumor grafts.