BINDING OF ANTI-DNA ANTIBODIES AS MEASURED FLUOROMETRICALLY BY ETHIDIUM-BROMIDE

  • 1 January 1978
    • journal article
    • research article
    • Vol. 5  (4) , 391-398
Abstract
The phenanthridine dye ethidium bromide (EB) intercalates with double-stranded (ds) DNA resulting in an enhancement of fluorescence. Single-stranded (ss) DNA does not show this fluorescent enhancement. Purified Ig[immunoglobulin]G from patients with systemic lupus erythematosus (SLE) containing anti-dsDNA antibodies [Ab] competes with EB for binding to DNA resulting in a decrease in fluorescence. Ab which bind ssDNA in the Millipore filter radioimmunoassay displace EB from dsDNA showing that antigenic determinants are available for binding in the ds molecule. This study introduces the EB assay and presents a comparison with the Millipore filter assay.