The aim of the proposed project is to investigate the biochemical makeup of H-2 antigens and their chemical and/or structral relationship to viral antigens on murine leukemia cells. Since it has been demonstrated that there are interactions between H-2 antigens and virus and that T-cell mediated killing of virus infected and transformed cells is H-2 restricted, a concerted effort will be made to elucidate the biochemical nature of H-2-virus interactions. Monoconal anti-H-2 antibody will be produced in order to circumvent problems due to contaminating antibody so frequently found in conventional anti-H-2 antisera. This antibody as well as highly specific antibody against viral antigens will be used to characterize the antigenic profile of virus infected and transformed cells. In addition these antibodies will be used to isolate H-2 and viral components from cell extracts via immunoprecipitation. The isolated antigens will be extensively characterized using biochemical micromethodology and their relationship with one another as well as their relationship to their counterparts on uninfected or untransformed cells established. Finally an effort will be made to determine whether chemical and/or structural alterations in the expression of H-2 antigens on leukemic cells correlate with the progress of the disease or the immune competence of the host. The information thus obtained should contribute significantly to our understanding of the role of H-2 antigens in tumor cell physiology and in host response to malignant disease and will make possible an accurate assessment of the potential of such cell surface alterations for immunodiagnosis and immunotherapy.