PROLONGED CANINE RENAL ALLOGRAFT SURVIVAL AFTER PRETREATMENT WITH SOLUBILIZED ANTIGEN

Abstract

Antigen pretreatment has been evaluated as a mechanism for improving allograft survival. Small doses of donor-specific antigen derived from spleen cells proved highly effective in providing consistent prolongation of canine renal allografts. The mean survival time for 11 dogs was 144 days with only six showing evidence of rejection at death. The antigen was solubilized by sonic disruption of trypsinized spleen cells and given i.v. for 2 weeks. It was essential to give small doses of azathioprine and methylprednisolone after transplantation; otherwise, no effect was observed. These doses of immunosuppressive drugs alone did not increase graft survival. Horse anti-dog lymphocyte serum, when substituted for drugs after transplantation, also had a synergistic action with the antigen pretreatment. Antigen therapy, rather than drugs, continued after renal allografting was of no value. When antigen was derived from nonspecific donors, allografts were prolonged in only two of eight dogs studied; there was more evidence of rejection in these two dogs than if specific donor antigen was used. It would appear that these results can be best explained as representing enhancement of allograft survival.