Tolerance to lipopolysaccharide involves mobilization of nuclear factor kappa B with predominance of p50 homodimers

J Biol Chem. 1994 Jun 24;269(25):17001-4.


Stimulation of the human monocytic cell line Mono Mac 6 with lipopolysaccharide (LPS) leads to rapid and transient expression of cytokines like tumor necrosis factor (TNF). When such cells are precultured for 2 days with a low dose of LPS (20 ng/ml) followed by stimulation with a high dose of LPS (1 microgram/ml), expression of the TNF gene is minimal, i.e. the cells are tolerant. In nuclear run-on analysis, such tolerant cells show only a low degree of transcription, indicating that tolerance operates at or upstream of the transcription level. The CD14 LPS receptor is, however, up-regulated (not down-regulated) in tolerant cells, and LPS can, in fact, still lead to activation of tolerant cells as evidenced by mobilization of the transcription factor nuclear factor kappa B (NF-kappa B). Resolution of the NF-kappa B complex in gel shift analysis shows that the binding protein, mobilized in naive Mono Mac 6 cells, consists mainly of p50-p65 heterodimers, while in tolerant cells, the p50 homodimer is predominant. This increase in p50 homodimers coincides with an increase in p105 mRNA, suggestive of a transcriptional up-regulation of p50. Reporter gene analysis reveals that the NF-kappa B complex mobilized in tolerant cells is functionally inactive in that NF-kappa B-dependent luciferase constructs containing the human immunodeficiency virus long terminal repeat or the TNF 5'-region show only minimal transactivation after LPS stimulation. Similar to Mono Mac 6 cells, primary blood monocytes, when precultured with a low dose of LPS, also become tolerant and produce little TNF after LPS stimulation. The tolerant blood monocytes also up-regulate CD14, and they mobilize NF-kappa B with a predominance of p50 homodimers. Taken together, these results demonstrate that tolerance to LPS is determined by post-receptor mechanisms that involve an altered composition of the NF-kappa B complex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, CD / metabolism*
  • Antigens, Differentiation, Myelomonocytic / metabolism*
  • Base Sequence
  • Cells, Cultured
  • DNA Primers / chemistry
  • Drug Tolerance
  • Gene Expression Regulation / drug effects
  • Humans
  • In Vitro Techniques
  • Lipopolysaccharide Receptors
  • Lipopolysaccharides / toxicity*
  • Molecular Sequence Data
  • Molecular Weight
  • Monocytes / drug effects
  • NF-kappa B / chemistry
  • NF-kappa B / metabolism*
  • RNA, Messenger / genetics
  • Signal Transduction
  • Tumor Necrosis Factor-alpha / biosynthesis
  • Up-Regulation


  • Antigens, CD
  • Antigens, Differentiation, Myelomonocytic
  • DNA Primers
  • Lipopolysaccharide Receptors
  • Lipopolysaccharides
  • NF-kappa B
  • RNA, Messenger
  • Tumor Necrosis Factor-alpha