Serum soluble interleukin-6 receptor in MRL/lpr mice is elevated with age and mediates the interleukin-6 signal

Eur J Immunol. 1993 May;23(5):1078-82. doi: 10.1002/eji.1830230515.


The characteristics of soluble interleukin-6 receptor (sIL-6R) in murine sera were examined. To investigate a relationship between serum sIL-6R level and autoimmune diseases, quantitative analysis of serum sIL-6R in MRL/lpr mice was performed by an enzyme-linked immunosorbent assay. The serum sIL-6R level in MRL/lpr mice of both sexes was below the detection limit (< 1.0 ng/ml) at 8 weeks of age, but it increased in accordance with age and reached 42 +/- 9.3 ng/ml in female and 31 +/- 13 ng/ml in male mice at 30 weeks of age. In MRL/+ mice, although an age-associated increase in serum sIL-6R level was observed, it was much less extensive than that in MRL/lpr mice. Elevated serum sIL-6R level at the age of 30 weeks was observed in female and male (NZB x NZW)F1 mice (32 +/- 10 ng/ml and 17 +/- 5.0 ng/ml, respectively), and male BXSB/Mpj Yaa mice (42 +/- 18 ng/ml), suggesting that elevated serum sIL-6R in aged mice is one of the characteristics of autoimmune-prone mice. Quantitative analysis of serum IL-6 in MRL/lpr revealed that the serum sIL-6R level correlated well with the serum IL-6 level. We also showed that sIL-6R in the sera from MRL/lpr mice could mediate the IL-6 functions through the IL-6 signal-transducing receptor component gp130, suggesting that elevated production of sIL-6R may partly contribute to development of autoimmune disease in MRL/lpr mice.

MeSH terms

  • Aging / immunology*
  • Animals
  • Autoimmune Diseases / blood*
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Interleukin-6 / blood
  • Interleukin-6 / pharmacology*
  • Lymphoproliferative Disorders / blood*
  • Male
  • Mice
  • Mice, Inbred AKR
  • Mice, Inbred C57BL
  • Mice, Inbred NZB
  • Receptors, Immunologic / analysis*
  • Receptors, Immunologic / physiology
  • Receptors, Interleukin-6
  • Recombinant Proteins / pharmacology


  • Interleukin-6
  • Receptors, Immunologic
  • Receptors, Interleukin-6
  • Recombinant Proteins