The histocompatibility requirements of ovarian grafts in mice.

Abstract

The possible exemption of grafts of the endocrine glands from the usual effects of the homograft reaction provides one of the important unsolved problems of the immunology of transplantation. Experiments have been carried out in mice to study the possibilities: (1) that the antigenic stimulus from the transplanted endocrine gland is quantitatively inadequate; and (2) that endocrine organs release a qualitatively weaker series of specific genetically controlled antigens than other normal tissues such as skin. The fate of ovarian homografts transplanted between various strains of ovariectomized mice (C3H, CBA, RIll, A, C57 Br.andLAC Grey) have been studied. The return and persistence of cycles of vaginal cornification after grafting was used as a criterion by which to assess the duration of the graft’s survival. In all the strain combinations used the hosts reacted vigorously and destroyed the graft (whether orthotopic or subcutaneous) before it could produce oestrogenic hormone. Transplantation of an ovarian homograft sensitizes the host to a degree which the use of the second set reaction to a subsequent skin graft cannot distinguish from the sensitivity induced by a first set skin graft. There is no suggestion from these experiments that the ovary provides an incomplete antigenic stimulus. Ten out of 105CBAstrain ovarian grafts and 14 out of 151Astrain ovarian grafts survived transplantation into spayedF2hosts for more than 100 days. These figures imply that the genes controlling transplantation segregated at not less than 8 or 9 loci. They are smaller than the earlier estimates of not less than 15 arrived at in similar experiments using skin. However, thoseF2mice which accepted ovarian transplants also accepted skin transplants subsequently and the differences between the two series of results must be ascribed to errors of random sampling for which there is evidence in the form of differences in the segregation of coat colour genes. If the results of the two series are pooled together the new estimate for the number of separate loci is about 10. Second-set ovarian grafts transplanted toF2hosts, which only destroyed a first ovarian graft after an extended period of acceptance, did not necessarily undergo an accelerated second-set response and may survive for much longer periods than did the first graft. The results of both series of experiments support the view that the homograft reaction against endocrine organs does not differ in vigour from that which is expressed against other normal tissues such as skin.