The use of polyethylene glycol precipitation to detect low-avidity anti-DNA antibodies in systemic lupus erythematosus

J Immunol Methods. 1980;39(1-2):165-80. doi: 10.1016/0022-1759(80)90305-1.

Abstract

With a recently introduced method for measurement of low-avidity anti-DNA, the polyethylene glycol (PEG) precipitation assay (Riley et al., 1979), high levels of DNA binding by normal human serum (NHS) were found when circular PM2-DNA was used as antigen. THe nature of this DNA binding was studied. The removal of low-density lipoproteins (LDL) from the serum, e.g., by Aerosil absorption, eliminated DNA binding by NHS. Purified LDL bound DNA to the same extent as NHS. Non-specific binding of NHS or LDL to DNA was prevented by adding dextran sulphate to the incubation mixture. Analysis on sucrose gradients showed that only large DNA-anti-DNA complexes were precipitated by 3.5% PEG. The PEG assay with dextran sulphate is a sensitive assay for low-avidity anti-DNA antibodies. It adds important information to results obtained with the Farr assay, which mainly detects antibodies of high avidity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Antinuclear / isolation & purification*
  • Antigen-Antibody Complex
  • DNA / immunology
  • Female
  • Humans
  • Immunosorbent Techniques*
  • Lupus Erythematosus, Systemic / immunology*
  • Polyethylene Glycols

Substances

  • Antibodies, Antinuclear
  • Antigen-Antibody Complex
  • Polyethylene Glycols
  • DNA