Abstract
The difference in the antigenic determinant size of DNA for sera from patients with SLE and rabbit anti-DNA sera were investigated. Haptenic inhibition studies were carried out by measuring the inhibition of [3H]DNA-antibody binding by three different types of oligonucleotides which were prepared from formic acid-diphenylamine digests, hydrazinolyzed digests and pancreatic DNase digests, respectively. Oligonucleotides from DNase I digests showed potent inhibitory activity with both SLE sera and rabbit sera. However, the inhibitory activities of purine and pyrimidine oligonucleotides were more potent for SLE sera than for rabbit anti-DNA sera. The determinant size estimated for rabbit sera was in the range of tetra- to heptanueleotide, while in SLE sera it was in the range of di- and trinucleotide.
