The proposed research is designed to characterize the target cell potential of the Abelson leukemia virus (A-MuLV). Antisera to Abelson virus transformed lymphomas will be analyzed in detail to determine surface molecules involved and the number of specificities present in the anti-B lymphocyte and anti-"pre-B" lymphocyte activities already detected. Preparation of monoclonal antibody to these determinants will be attempted by plasmacytoma hybridization with immunized rat spleen cells. The ability of A-MuLV and derivatives of A-MuLV to transform antigen-specific lymphocyte populations will be tested in an attempt to provide an antigen-specific B lymphoma. Such a cell line would possibly provide a model system for studying the biochemical events of immune induction and paralysis. Hybrids of A-MuLV-transformed lymphomas with various cell types including normal spleen cells, LPS blasts, and various types of cell lines will be analyzed to determine the effect on A-MuLV expression.