The overall objective of the proposed research is the study of the regulation of cellular immune responses both clinically and in experimental animals with the goal of applying the information obtained to problems of clinical organ transplantation and immunity to solid tumors. Particular emphasis will be placed on the investigation of the immunosuppressive properties of an immunoregulatory alphaglobulin (IRA) extracted from normal human serum. Clinical studies will include an evaluation of the presence of high levels of IRA-like activity in patients with advanced cancer or who have suffered recent trauma. Laboratory studies include the development of a specific immunoassay for IRA for future clinical application and the use of IRA alone or in combination with other immunosuppressive agents in attempts to induce immunological tolerance to tissue allografts in experimental animals. Moreover, we will apply the RNA-mediated transfer of cellular immunity in studies designed to transfer tumor specific immunity in inbred mice and to human lymphocytes in vitro and will continue a study of the biochemical mechanisms involved in this transfer system.