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
Kashimura, M.; Wakizaka, A.; Kurosaka, K.; Okuhara, E.; Akihama, T.; Miura, A.B.; Shibata, A.
Clinical and Experimental Immunology 43(2): 223-230
1981
ISSN/ISBN: 0009-9104 PMID: 6168422 Document Number: 180838
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.