Enhanced B7-2 gene expression by interferon-gamma in human monocytic cells is controlled through transcriptional and posttranscriptional mechanisms

Blood. 1999 Sep 1;94(5):1782-9.


B7-2 is a costimulatory molecule expressed on professional antigen-presenting cells that provides T cells with a critical signal resulting in T-cell activation. Interferon-gamma (IFN-gamma) enhances B7-2 protein expression in monocytic cells. However, the molecular mechanisms controlling the enhanced expression of B7-2 are poorly understood. Northern blot and flow cytometry analysis revealed that human monocytes and the human monocytic cell line MonoMac6 (MM6) constitutively expressed B7-2 mRNA and protein and IFN-gamma treatment further enhanced the expression of both molecules. The ability of IFN-gamma to enhance B7-2 mRNA was evident at the dose of 31 U/mL and reached plateau levels at 500 U/mL. The effects of IFN-gamma on B7-2 mRNA expression were time dependent and occurred within 3 hours of treatment and increased through 24 hours. In vitro transcription assays and mRNA stability experiments showed that IFN-gamma increases both transcriptional activity and the stability of B7-2 mRNA. Treatment of MM6 cells with cycloheximide showed that de novo protein synthesis was not required for the IFN-gamma-enhanced expression of B7-2 mRNA. Overall, these studies show for the first time that IFN-gamma-enhanced expression of B7-2 protein in human monocytic cells is controlled at the gene level through a dual mechanism involving transcriptional and posttranscriptional mechanisms.

MeSH terms

  • Antigens, CD / biosynthesis*
  • Antigens, CD / genetics
  • Antiviral Agents / pharmacology*
  • B7-2 Antigen
  • Cells, Cultured
  • Gene Expression Regulation / drug effects
  • Humans
  • Interferon-gamma / pharmacology*
  • Membrane Glycoproteins / biosynthesis*
  • Membrane Glycoproteins / genetics
  • Monocytes / physiology*
  • RNA Processing, Post-Transcriptional / drug effects
  • Transcription, Genetic


  • Antigens, CD
  • Antiviral Agents
  • B7-2 Antigen
  • CD86 protein, human
  • Membrane Glycoproteins
  • Interferon-gamma