The effect of hydroxyl radical on the antigenicity of native DNA.
Hydroxyl free-radical mediated in vitro modification of native calf thymus DNA showed single-strand breaks, decrease in melting temperature and structural alteration of purine and pyrimidine bases. Experimentally induced antibodies against modified DNA exhibited polyspecificity. Native DNA, RNA and synthetic polynucleotides in B-conformation were found to be an effective inhibitor of induced antibody-immunogen interaction. Naturally occurring human anti-DNA autoantibodies showed enhanced recognition of modified DNA as compared to native polymer. IgG isolated from anti-DNA antibody-positive SLE sera by Protein A-Sepharose 4B chromatography were affinity purified on nDNA-(polylysyl-Sepharose 4B) matrix. In competitive binding experiments, the affinity-isolated IgG showed almost equal recognition of both native DNA and hydroxyl radical modified DNA. The possible role of hydroxyl radicals in the etiopathogenesis of SLE has been discussed.
Alam
K
K
Department of Biochemistry, Faculty of Medicine, A.M.U., Aligarh, India.
Ali
A
A
Ali
R
R
D000818:Animals; D000906:Antibodies / Q000276:immunology; D000941:Antigens / Q000276:immunology*; D001667:Binding, Competitive; D002417:Cattle; D002499:Centrifugation, Density Gradient; D004247:DNA / Q000737:chemistry / Q000187:drug effects / Q000276:immunology*; D004278:DNA, Superhelical / Q000187:drug effects; D006358:Hot Temperature; D006878:Hydroxides / Q000494:pharmacology*; D017665:Hydroxyl Radical; D007074:Immunoglobulin G / Q000276:immunology; D009691:Nucleic Acid Denaturation; D013056:Spectrophotometry, Ultraviolet
D000906:Antibodies; D000941:Antigens; D004278:DNA, Superhelical; D006878:Hydroxides; D007074:Immunoglobulin G; D017665:Hydroxyl Radical; D004247:DNA