Through the analysis of selected idiotypes, we hope to continue our characterization of anti-DNA antibodies in the human disease, systemic lupus erythematosus, and in two murine models. New anti-idiotypes will be generated to identify the structural basis for DNA binding and to characterize subsets of anti-DNA antibodies that differ in pathogenicity. We will generate idiotype positive anti-DNA antibody producing cell lines from SLE patients and from autoimmune mice. Using these lines, we will determine whether there are germ line immunoglobulin variable region genes that encode anti-DNA antibodies or whether anti-DNA antibodies are the consequence of somatic mutation in germ line immunoglobulin genes.