Prolongation of murine skin allograft survival by immunologic manipulation with anti-interleukin 2 receptor antibody.

Administration of a rat monoclonal antibody (M7/20) directed against the murine interleukin 2 (IL 2) receptor in combination with sublethal x-irradiation of the recipient significantly enhanced the survival of skin allografts, both when the grafts were MHC disparate from the hosts and when only minor histocompatibility differences were present compared with untreated controls. No prolongation in graft survival was seen with either treatment alone at the dose employed. M7/20 and x-ray-treated allograft recipients also displayed significantly decreased alloantigen-specific reactivity against donor-strain spleen cells in both delayed-type hypersensitivity and cytotoxicity assays. Thus, such combination treatment reduces expression of host immune reactivity against graft determinants by several criteria. This work provides additional evidence that monoclonal antibodies directed against the IL 2 receptor may be useful in clinical transplantation.