The role of interleukin-6 in mitogenic T-cell activation: detection of interleukin-2 heteronuclear RNA by polymerase chain reaction

Cell Immunol. 1991 May;134(2):511-9. doi: 10.1016/0008-8749(91)90322-3.


It has been documented that interleukin-6 (IL-6) supports the proliferation of purified, anti-CD3-stimulated murine T cells. We found that stimulation of human peripheral blood mononuclear cells (PBMCs) with anti-CD3 induced a significant accumulation of IL-6 mRNA, indicating that antigen-mediated T-cell activation may involve IL-6 release from accessory cells. Phytohemagglutinin (PHA) had little effect upon IL-6 gene expression. In keeping with these findings, anti-IL-6 reduced but did not abolish anti-CD3-mediated proliferation of PBMCs, but had no significant effect upon PHA-stimulated proliferation. The addition of recombinant (r) IL-6 enhanced the proliferation of anti-CD3-stimulated PBMCs and increased the accumulation of IL-2 mRNA in PHA-stimulated PBMCs during the first 5 hr of culture. Nuclear run-off experiments did not reveal significant changes in IL-2 transcription in PHA plus rIL-6-treated PBMCs attempting to assume that IL-6 mediates stabilization of IL-2 mRNA. However, monitoring of partially spliced IL-2 mRNA by polymerase chain reaction revealed a clear increase in IL-2 heteronuclear RNA. Thus IL-6 increases the rate of IL-2 transcription which was not detectable by conventional in vitro transcription assays. We conclude that anti-CD3 triggers T-cell proliferation through a process that is partially but not entirely dependent upon release of IL-6. IL-6, in turn, supports IL-2 transcription. Insofar as anti-CD3 mimics antigen-triggered activation of the T-cell receptor complex, IL-6 appears to support the early immune response by augmenting antigen-triggered IL-2 gene expression.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibodies, Monoclonal / immunology
  • Antigens, Differentiation, T-Lymphocyte / physiology
  • Base Sequence
  • CD3 Complex
  • Cells, Cultured
  • Humans
  • Interleukin-2 / genetics*
  • Interleukin-6 / analysis
  • Interleukin-6 / pharmacology*
  • Lymphocyte Activation*
  • Molecular Sequence Data
  • Polymerase Chain Reaction*
  • RNA, Messenger / analysis*
  • Receptors, Antigen, T-Cell / physiology
  • Recombinant Proteins / pharmacology
  • T-Lymphocytes / immunology*
  • Transcription, Genetic / drug effects


  • Antibodies, Monoclonal
  • Antigens, Differentiation, T-Lymphocyte
  • CD3 Complex
  • Interleukin-2
  • Interleukin-6
  • RNA, Messenger
  • Receptors, Antigen, T-Cell
  • Recombinant Proteins