Hybridoma-produced autoantibodies to DNA will be used to analyze genetic and cellular aspects of experimental systemic lupus erythematosus. These monoclonal autoantibodies, together with corresponding anti-idiotypic antibodies will be employed to quantitate cross reactive idiotypes in serum as well as suppressor T cells, helper T cells and B cells with specificity for autoantibodies to DNA. Experiments will be done in MRL/I mice, which develop a severe and rapidly fatal form of systemic lupus erythematosus. The hybridoma autoantibodies will also be used to study recognition of helical nucleic acids by proteins.