Soluble interleukin 2 receptors abrogate IL-2 induced activation of peripheral mononuclear cells

Cytokine. 1994 Jul;6(4):358-64. doi: 10.1016/1043-4666(94)90058-2.


Soluble interleukin 2 receptors (sIL-2R) exert a potential role in immunoregulation. We investigated the in vitro effects of sIL-2R on several interleukin 2 (IL-2)-dependent cellular events. Cytotoxicity of human rIL-2-stimulated PBMC against K562 and Daudi was correlated inversely to the concentration of sIL-2R in the culture medium during rIL-2 stimulation. sIL-2R concentrations higher than 4.0 pM produced a significant loss of cytotoxicity (P < 0.01). The effect of different sIL-2R concentrations added to cultured human PBMC on secondary sIL-2R production was tested by ELISA. Secondary sIL-2R production was abrogated by high initial sIL-2R dosages whereas low initial dosages were followed by a continuing production of secondary sIL-2R after five days of culture. Proliferation of the IL-2-dependent mouse cell line CTLL-2-was suppressed by sIL-2R added to the culture medium in a dose-dependent way. The neutralizing capacity of sIL-2R strongly depended on the initial number of CTLL set in per proliferation assay. In contrast, variation of rIL-2-concentration had no significant effect on reduction of proliferation by sIL-2R. Furthermore, preincubation of sIL-2R with rIL-2 did not enhance growth suppression. These last findings indicate that there is at least no functional interaction between sIL-2R and free IL-2, whereas an interaction of sIL-2R with the membrane-bound receptor for IL-2 seems possible.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Cell Division / drug effects
  • Cell Line
  • Cells, Cultured
  • Cytotoxicity Tests, Immunologic
  • Humans
  • Interleukin-2 / pharmacology*
  • Leukocyte Count / drug effects
  • Leukocytes, Mononuclear / drug effects*
  • Mice
  • Receptors, Interleukin-2 / biosynthesis
  • Receptors, Interleukin-2 / physiology*
  • Recombinant Proteins / pharmacology
  • Solubility


  • Interleukin-2
  • Receptors, Interleukin-2
  • Recombinant Proteins