Detection of anti-DNA antibodies by counterimmunoelectrophoresis

Abstract The technique of counterimmunoelectrophoresis (CIE) has been adapted for the purpose of detecting and quantitating serum anti-DNA precipitating antibody. Ionagar No. 2 and Tris-HCl buffer were employed. Conditions for electrophoresis were 5.4 V per linear cm of agar, 20.0 mA per slide, and a 20 min migration interval. Pyronin staining was used to facilitate the presence of DNA in precipitin bands. Clear-cut, dense DNA anti-DNA precipitin bands were detectable by CIE using selected reference human sera from patients with systemic lupus erythematosus. Precipitin activity was absorbable with DNA and with a goat anti-IgG immunosorbent. Precipitins were also detected in ammonium sulfate-precipitated serum fractions and in IgG-rich fractions obtained by DEAE-cellulose chromatography. CIE would seem to offer advantages of simplicity and rapid reproducibility in screening large numbers of serum samples for anti-DNA precipitating antibody.