Isolation of Human Anti‐idiotypes Broadly Cross Reactive with Anti‐dsDNA Antibodies from Patients with Systemic Lupus Erythematosus

Antibodies to double stranded (ds)DNA play a central role in clinical diagnosis and disease expression in Systemic lupus erythematosus (SLE). This paper describes the isolation of anti-idiotype reagents (anti/antidsDNA) from four SLE sera and the demonstration of broad and quantitatively similar cross reactivity to both polyclonal and monoclonal anti-dsDNA antibodies isolated from SLE patients. Seven affinity-purified polyclonal and three monoclonal human anti-dsDNA preparations reacted preferentially with anti-idiotype F(ab')(2) coated plates compared to normal immunoglobulin (Ig)G F(ab')(2) coated plates in ELISA. In contrast, autoantibodies of other specificities (anti-Ro/SSA, anti-La/SSB, and anti-U(1)RNP) reacted equally with anti/anti-dsDNA F(ab')(2) and normal IgG F(ab')(2) coated plates. Such anti-idiotypic antibodies could play a significant role in the regulation of anti-dsDNA antibody levels in SLE.