title: Hidden high-avidity anti-DNA antibodies occur in normal human gammaglobulin preparations.
abstract: An ability to detect hidden high-avidity DNA-binding protein in human gammaglobulin samples was investigated. Using ion exchange chromatography on QAE-Sephadex A-50 a highly positive Farr assay DNA-binding fraction was reproducibly isolated from several commercial normal human gammaglobulin preparations. The estimated dissociation constant had a value of 1.04 x 10(-11) M thus confirming high avidity protein-DNA complex formation. Anti-DNA antibodies (Ab) ELISA data revealed that immunoglobulin (Ig) G, IgM and IgA participated in the protein-DNA interaction. Inhibitory experiments involving a number of polynucleotides, synthetic and natural polyanions demonstrated that both double-stranded DNA (dsDNA) and heat-denatured DNA but not RNA inhibited the protein-3H-DNA binding. Generally, the inhibiting effect was more pronounced when purine base-containing polynucleotides and polydeoxy- rather than polyribonucleotides were used. Synthetic polyanions and normal human sera (NHS) also markedly reduced the binding. The presence of hidden high-avidity DNA-binding antibodies in normal gammaglobulin preparations was suggested.
mesh_terms: D000974:Antibodies, Antinuclear / Q000276:immunology* / Q000378:metabolism; D000915:Antibody Affinity; D000918:Antibody Specificity; D002852:Chromatography, Ion Exchange; D004247:DNA / Q000276:immunology / Q000378:metabolism; D004306:Dose-Response Relationship, Immunologic; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D012313:RNA / Q000378:metabolism; D015531:Radioimmunoprecipitation Assay; D005719:gamma-Globulins / Q000276:immunology*
chemical_list: D000974:Antibodies, Antinuclear; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D005719:gamma-Globulins; D012313:RNA; D004247:DNA