THE REACTIVITY OF SERA FROM PATIENTS WITH SYSTEMIC LUPUS-ERYTHEMATOSUS TO 7 DIFFERENT SPECIES OF SINGLE AND DOUBLE-STRANDED DEOXYRIBONUCLEIC ACIDS

Objective. Anti-DNA antibodies are frequently found in the serum of pa tients with systemic lupus erythematosus (SLE). To understand whether the avidity of SLE sera to different species of single-stranded (ss) a nd double-stranded (ds) DNA is different or not, the reactivity of act ive SLE sera to seven species of DNA from viral, bacterial, piscine, a nd mammalian sources was compared. Methods. Nineteen sera from patient s with active SLE were studied for their reactivity to different ssDNA and dsDNA from Escherichia coli (EC) Micrococcus lysodeikticus (ML), Clostridium perfringens (CP), calf thymus (CT), salmon testis (ST), hu man placenta (HP) and lambda phage by ELISA. The dsDNA was purified by treating it with S-1 nuclease and proteinase K, followed by Sephacryl S-300 gel filtration. The ssDNA was purified by absorption on a hydro xyapatite column after heat-cleavage of the dsDNA. Results. The reacti vity of SLE sera to 7 species of dsDNA was not significantly different and they recognized a more widely shared epitope. In contrast, the re activity of these sera to 7 species of ssDNA was erratic and the antig ens could be grouped into high (CP and HP), medium (EC, ML, CT, and ST ) and low (lambda-phage) antigenicities. Conclusion. The anti-ssDNA an d anti-dsDNA antibodies of SLE patients recognize more widely shared d eterminants on the DNA of seven different species. Lambda-phage DNA sh ows the poorest immunogenicity among them.