CpG motif-containing DNA fragments from sera of patients with systemic lupus erythematosus proliferate mononuclear cells in vitro

J Rheumatol. 1999 Feb;26(2):294-301.


Objective: To characterize DNA in sera of patients with systemic lupus erythematosus (SLE) in terms of size, guanine plus cytosine (G+C) content (by percentage), CpG dinucleotide (CpG) (percentage), and effects on mononuclear cells (MNC).

Methods: Nine DNA clones were sequenced. Oligodeoxynucleotides with the characteristic CpG motif (TTCGAA or PuPuCGPyPy) were examined for their proliferative effect on MNC by [3H]thymidine incorporation, expression of HLA-DR and intercellular adhesion molecule (ICAM)-1 on monocytes by flow cytometry, and mRNA levels encoding interleukin 12 (IL-12) and interferon-gamma (IFN-gamma) by semiquantitative reverse transcription polymerase chain reaction.

Results: The size of DNA clones ranged from 87 to 318 bp (mean +/- SD, 177+/-68) and enrichment in G+C and CpG ranged from 34.7 to 69.7% (48.1+/-10.7) and 0.63 to 12.8% (4.0+/-4.1), respectively. Three of 9 clones contained the characteristic CpG motif. Oligonucleotides proliferated MNC, and augmented HLA-DR and ICAM-1 expression in company with an increase of mRNA encoding IL-12 and IFN-gamma.

Conclusion: Circulating CpG motif-containing DNA fragments in SLE increased mRNA encoding IL-12 and IFN-gamma, which in turn increased HLA-DR and ICAM-1 on monocytes, resulting in MNC proliferation. This mechanism could contribute to the pathogenesis of SLE.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cell Division / drug effects
  • Cells, Cultured
  • CpG Islands / genetics
  • CpG Islands / physiology*
  • DNA / chemistry*
  • DNA / physiology
  • Fatty Acids, Monounsaturated / metabolism
  • HLA-DR Antigens / blood
  • Humans
  • In Vitro Techniques
  • Intercellular Adhesion Molecule-1 / blood
  • Interferon-gamma / genetics
  • Interleukin-12 / genetics
  • Leukocytes, Mononuclear / cytology*
  • Leukocytes, Mononuclear / drug effects*
  • Lupus Erythematosus, Systemic / genetics
  • Lupus Erythematosus, Systemic / immunology*
  • Lymphocyte Activation / drug effects
  • Lymphocyte Activation / genetics
  • Molecular Sequence Data
  • Oligonucleotide Probes / pharmacology
  • Quaternary Ammonium Compounds / metabolism
  • RNA, Messenger / blood
  • Reverse Transcriptase Polymerase Chain Reaction


  • Fatty Acids, Monounsaturated
  • HLA-DR Antigens
  • Oligonucleotide Probes
  • Quaternary Ammonium Compounds
  • RNA, Messenger
  • Intercellular Adhesion Molecule-1
  • Interleukin-12
  • Interferon-gamma
  • DNA
  • 1,2-dioleoyloxy-3-(trimethylammonium)propane