Induction of specific tolerance by 15-deoxyspergualin (DOS) treatment after rat skin and kidney transplantation in rats. Analysis of effectivity of various protocols of DOS application.

The purpose of this study was to analyse the effect of various protocols of 15-deoxyspergualin (DOS) application on skin or kidney graft survival. Following rat strain combinations were used: AS-->LEW (MHC identical/non-MHC-different) and DA-->LEW (MHC-different/non-MHC-different). Reference DOS dose was 2.5 mg/kg, i.p. It was shown that the effect of DOS depended on multiple factors, such as: type of tissue or organ, onset of treatment, drug dose and length of drug application. In skin transplantation graft survival was 32-34 days in AS-->LEW and 24-26 days in DA-->LEW. Kidney graft survived more than 150 days. DOS prolonged skin survival when the application was started earlier than day 8, whereas kidney graft survived only when DOS treatment was started not later than 3-4 days after transplantation. In skin transplantation a dose of 0.3 mg/kg had a small effect-prolongation graft survival up to 4 days. Higher doses induced longer graft survival, however, maximal survival of allogeneic skin was 22 days. In kidney transplantation a dose of 0.3 mg/kg led to prolonged graft survival-up to 150 days. Doses of 2.0-2.5 mg/kg were able to induce specific tolerance. The optimal skin or kidney graft survival was obtained when DOS was applied for 14 days. Shorter than 12-day treatment with DOS led to a shorter graft survival. When donor was pretreated with DOS prolongation of non-allogeneic graft survival was observed. Our results showed that short-term application of DOS is safe and effective. To obtain optimal DOS effect the drug application must be started directly after transplantation.