Is α-actinin a target for pathogenic anti-DNA antibodies in lupus nephritis?
Objective: Following recent reports that pathogenic murine anti-DNA antibodies bind to -actinin, it was obviously of interest to assess the ability of human pathogenic anti-double-stranded DNA (anti-dsDNA) antibodies to bind this antigen. Both human monoclonal anti-DNA antibodies and antibodies affinity purified from the sera of patients with systemic lupus erythematosus (SLE) were investigated. Methods: An enzyme-linked immunosorbent assay was established to measure immunoglobulin binding to -actinin. Antibodies binding dsDNA were purified from the sera of SLE patients who either had active renal disease or had never had renal disease. Serum samples were selected at times when the patients’ sera exhibited high IgG binding to dsDNA. The binding of supernatants from 3 high-affinity human anti-dsDNA IgG hybridomas (RH14, B3, and DIL-6) and 7 human IgM anti-DNA hybridomas was also investigated. Results: A greater proportion of anti-dsDNA IgG-binding antibodies purified from patients with
