Gene usage by an anti-U1 snRNP 70K monoclonal autoantibody derived from a lupus-prone mouse.

Analysis of gene usage can provide insight into the structure, function, molecular genetics and regulation of antibodies, and in the case of autoantibodies perhaps provide immunopathological insight into autoimmune disease. Antibodies reactive with the U1 small nuclear ribonucleoprotein 70 K protein are common in mixed connective tissue disease and systemic lupus erythematosus. The monoclonal antibody 2.73 was spontaneously derived from a lupus-prone mouse and is reactive with 70 K. The polymerase chain reaction was used to amplify heavy and light chain cDNA from the 2.73 hybridoma. Genetic analysis revealed homology with other unrelated antibodies. Immunization of non-autoimmune mice with the purified 2.73 antibody induced autoantibodies towards 70 K and DNA. These results may implicate 2.73 involvement in the generation and/or maintenance of autoantibodies in lupus.