Effect of metacycloprodigiosin, an inhibitor of killer T cells, on murine skin and heart transplants

Metacycloprodigiosin is an antibiotic that has been shown to suppress T-cell proliferation induced by concanavalin A in vitro. We examined the effect of metacycloprodigiosin on murine allogeneic skin and heart transplantation models, and compared graft rejection with donor-specific cytotoxic T-cells and antibody activity. The antibiotic slightly prolonged the survival of C57B1/6 heart and skin grafts in BALB/c mice, although the effect was less than that of cyclosporin A. The effect was more evident in Bm1 (H-2D mutant) skin grafts on C57B1/6 hosts or in a minor histocompatibility antigen-mismatched model. In contrast, metacycloprodigiosin suppressed anti-graft cytotoxic T-cell activity of BALB/c spleen grafted with C57B1/6 skin as comparable to cyclosporin A, but had only partial effect on antibody production. Thus, metacycloprodigiosin is more effective in reducing splenic cytotoxic T-cell activity than in prolonging murine skin or cardiac allografts.