Brief Definitive Report Haptens Can Serve as Surrogate Transplantation Antigens in a Manner That Demonstrates H-2 Restriction of Graft Rejection*

Contact hypersensitivity (CH) to simple haptens and acute allograft rejection are generally regarded as T cell-mediated responses. However, at the present time, considerable controversy exists concerning the precise phenotype of the effector cells that are the proximate causes of inf lammation and tissue destruction. In transplantation immunity, the assumption of a decade a g o t h a t cytotoxic T lymphocytes, predominately of the Lyt-1-23 + type, are the mediators of acute allograft re ject ion-has been strongly challenged by recent data identifying the T cell subpopulat ion that mediates delayed-type hypersensitivity reactions (TD-rn, Lytl+23 -) as an equally (if not more so) important part icipant in specific graft destruction (1, 2). Similarly, the general belief that TDTH cells mediate contact hypersensitivity (3) has been challenged by Tagar t (4) and more recently by Sunday and Dorf (5), who have demonstrated a role for cytotoxic T cells in the deve!opment of C H reactions in the skin. In this time of controversy, our laboratory has been involved in the study of both transplantat ion immuni ty and contact hypersensitivity and it seemed that useful information might emerge from experiments designed to study both types of cell-mediated immunities simultaneously. The experiments and results to be described examine the possibility that hapten-derived skin grafts can serve as the targets of an immune response elicited by typical contact hypersensitivity-inducing regimens.