Prolongation of allograft and xenograft survival by pretreatment with prednisolone and donor-specific antigen.

Sprague-Dawley rats were grafted with skin of Wistar rats. Surprisingly, pretreatment with donor-specific spleen homogenate and semisoluble antigens combined with prednisolone resulted in a prolonged survival of the skin grafts. The same effects were observed after transplantation of rabbit skin to Sprague-Dawley rats. Lewis rats were grafted with kidneys of LewisX brown-Norway F1 rats and simultaneously subjected to bilateral nephrectomy. The recipients were pretreated with soluble and with semisoluble donor-specific antigen. The recipients survived in definitely after pretreatment with semisoluble antigen combined with prednisolone. Combined administration of soluble antigen and prednisolone was ineffective. In the canine kidney allografts, the recipients were pretreated with semisoluble donor-specific spleen antigen; in the canine liver allografts, they were given soluble and semisoluble antigen. The canine kidney recipients survived significantly longer when they had been pretreated with antigens combined with high doses of prednisolone. Pretreatment with high doses of prednisolone alone did not prolong the survival of kidney grafted rats and dogs, and pretreatment with antigen alone had no effect on the survival of kidney grafted dogs. Pretreatment with antigen alone had no effect on the survival time of liver allografts in dogs, but the recipients of the liver grafts survived longer than and controls--some of them for more than 1,200 days--when they had been pretreated with antigens combined with prednisolone. In this respect, the semisoluble antigen was more effective than the soluble form. After three spaced antigen injections, the lymphocytotoxic antibody titers on the day of the grafting varied, but they were always low. There was no correlation between the titers on the day of transplantation and the duration of survival. Recipients pretreated with antigen showed lower postoperative antibody titers than those without antigen.