Up-regulation of intercellular adhesion molecule 1 transcription by hepatitis B virus X protein

Proc Natl Acad Sci U S A. 1992 Dec 1;89(23):11441-5. doi: 10.1073/pnas.89.23.11441.


Intercellular adhesion molecule 1 (ICAM-1), a counter-receptor for lymphocyte function-associated antigen 1 on T cells, is critically important to a wide variety of adhesion-dependent leukocyte functions, including antigen presentation and target cell lysis. ICAM-1 expression by hepatocytes is increased in areas of inflammation and necrosis during chronic hepatitis B. Whether induction of ICAM-1 is due to the effect of inflammatory cytokines or involves a direct effect of the hepatitis B virus (HBV) remains unknown. In the present study, transfection of the HBV genome into human hepatoma cell lines resulted in enhanced expression of ICAM-1 protein and RNA in the absence of inflammation. Results of subgenomic transfections indicated that the HBV X protein (pX) induced ICAM-1 expression. Nuclear run-on assays showed that pX induced the ICAM-1 gene by increasing its rate of transcription. Although both pX and interferon gamma induced transcription of ICAM-1, addition of interferon gamma to cells expressing pX did not show an additive or synergistic effect. These results indicate that pX can directly regulate expression of ICAM-1 and may participate in the immunopathogenesis of HBV infection.

MeSH terms

  • Cell Adhesion Molecules / genetics*
  • Gene Expression Regulation, Viral* / drug effects
  • Genes
  • Hepatitis B virus / genetics*
  • Humans
  • In Vitro Techniques
  • Intercellular Adhesion Molecule-1
  • Interferon-gamma / pharmacology
  • Liver / physiology*
  • RNA, Messenger / genetics
  • Trans-Activators / genetics*
  • Transcription, Genetic / drug effects
  • Transfection
  • Tumor Cells, Cultured
  • Viral Proteins / genetics
  • Viral Regulatory and Accessory Proteins


  • Cell Adhesion Molecules
  • RNA, Messenger
  • Trans-Activators
  • Viral Proteins
  • Viral Regulatory and Accessory Proteins
  • hepatitis B virus X protein
  • Intercellular Adhesion Molecule-1
  • Interferon-gamma