title: Prolongation of skin allograft survival in rats by a novel immunosuppressive agent, FK506.
abstract: FK506, an immunosuppresant, was isolated from Streptomyces tsukubaensis. Intramuscular administration of FK506 (0.32 mg/kg or more) 5 days a week for two weeks after grafting prolonged the acceptance time of F344 skin allograft to WKA rats. Similar results were obtained with cyclosporine at 32 mg/kg or more, but other immunosuppressives (i.e., prednisolone, azathioprine, and bredinin) gave only a marginal prolongation. The prolonging effect of FK506 was obtained in various donor-recipient combinations across a major or minor histocompatibility barrier. The agent also prolonged the acceptance time of mouse skin xenografts to rats. Furthermore, maintenance doses of 3.2 or 0.32 mg/kg twice a week after an initial 14-day treatment with the agent at 3.2 mg/kg gave graft survival as long as the treatment was continued for more than 120 days. Our findings show that FK506 has a potent immunosuppressive effect in rats and suggest that the agent merits further investigation.
mesh_terms: D000818:Animals; D003524:Cyclosporins / Q000494:pharmacology; D006085:Graft Survival / Q000187:drug effects*; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL / Q000276:immunology; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains / Q000276:immunology; D016038:Skin Transplantation; D016559:Tacrolimus; D014183:Transplantation, Heterologous; D014184:Transplantation, Homologous
chemical_list: D003524:Cyclosporins; D007166:Immunosuppressive Agents; D011725:Pyridines; D016559:Tacrolimus