DNA interference with radioimmunoassay procedures.
A bacterial factor preventing precipitation of immune complexes was purified from a culture of Streptococcus faecalis (AK strain) by gel filtration on Sephadex G-100 and Bio-Gel A-150m columns. The factor was identified as DNA on the basis of its ultraviolet absorption maximum at 260 nm, hydrolysis by deoxyribonuclease, Mr exceeding 1.5 X 10(8), and positive reaction with diphenylamine. DNA interferes with the immunoassay by preventing precipitation of immune complexes. Only double-stranded DNA and polynucleotides showed this property. Evidently, double-stranded DNA will give false-positive interference with the usual RIA procedures.
D000936:Antigen-Antibody Complex / Q000302:isolation & purification; D006063:Chorionic Gonadotropin / Q000032:analysis / Q000302:isolation & purification; D002850:Chromatography, Gel; D004269:DNA, Bacterial / Q000032:analysis* / Q000302:isolation & purification; D013293:Enterococcus faecalis / Q000032:analysis*; D005189:False Positive Reactions; D011863:Radioimmunoassay
D000936:Antigen-Antibody Complex; D006063:Chorionic Gonadotropin; D004269:DNA, Bacterial