title: Antigenic structure of DNA: relatively high inhibitory activity of di- and trideoxyribonucleotide derived from DNase digest on the interaction of thermally denatured DNA with systemic lupus erythematosus sera.
abstract: The antigenic determinant of thermally denatured DNA reactive with systemic lupus erythematosus (SLE) sera was examined by hapten inhibition assay. We used oligonucleotides with different chain lengths (2-8) derived from DNase I digests of salmon sperm DNA in Farr's radioimmunoassay with thermally denatured mouse embryo 3H-DNA as antigen, and the effect of dextran sulphate addition to the assay mixture on the inhibitory activity of oligonucleotides was examined. A characteristic oligonucleotide inhibition pattern on DNA binding by SLE sera was observed in the assay system without dextran sulphate. Di-and/or trinucleotide inhibited the binding more effectively than tetra-and/or pentanucleotide. These patterns were also observed in DNA-normal serum interaction. When dextran sulphate was added to the mixture, the inhibition pattern changed; the inhibitory activity of oligonucleotides increased with chain length in both serum groups. The inhibitory potency of di- and trinucleotide was higher on DNA-SLE sera than on DNA-normal sera interaction. The high potency of short-chain oligomers in SLE sera is obviously different from that in experimentally elicited anti-DNA sera suggesting that different mechanism(s) are involved in antibody production in normal individuals and SLE patients.
mesh_terms: D000328:Adult; D000937:Antigen-Antibody Reactions / Q000187:drug effects; D001666:Binding Sites, Antibody / Q000187:drug effects; D004247:DNA / Q000276:immunology*; D000939:Epitopes / Q000032:analysis*; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D009841:Oligonucleotides / Q000276:immunology / Q000494:pharmacology
chemical_list: D000939:Epitopes; D009841:Oligonucleotides; D004247:DNA