Chloroquine inhibits production of TNF-alpha, IL-1beta and IL-6 from lipopolysaccharide-stimulated human monocytes/macrophages by different modes

Rheumatology (Oxford). 2006 Jun;45(6):703-10. doi: 10.1093/rheumatology/kei282. Epub 2006 Jan 17.


Objectives: TNF-alpha, IL-1 and IL-6 are known to have primary roles in the pathogenesis of rheumatoid arthritis and other inflammatory diseases. The anti-rheumatic drug chloroquine has been shown to inhibit TNF-alpha, IL-1 and IL-6 production from mononuclear phagocytes. We examined the underlying mechanisms involved in the chloroquine-induced inhibition of cytokine production.

Methods: Human peripheral blood mononuclear cells and monocytes/macrophages and monocytic U-937 and THP-1 cells were stimulated with lipopolysaccharide, and TNF-alpha, IL-1beta and IL-6 production was measured by ELISA. Levels of mRNA were measured by northern blotting and reverse transcription-polymerase chain reaction. Synthesis of 26-kDa TNF-alpha precursor was measured by metabolic labelling and immunoprecipitation analysis. Transcription rate was determined by nuclear run-on assay.

Results: TNF-alpha release from the cells was inhibited by chloroquine, whereas the steady-state level of TNF-alpha mRNA and synthesis of 26-kDa TNF-alpha precursor were not changed by chloroquine. In contrast, chloroquine-induced inhibition of IL-1beta and IL-6 release was accompanied by a decrease in their steady-state mRNA levels. The transcription rates of the IL-1beta and IL-6 genes were not changed by chloroquine, whereas the stability of IL-1beta and IL-6 mRNA was decreased by chloroquine. Weak-base amines such as methylamine and ammonium chloride had no effect on the production of TNF-alpha, whereas they partially blocked the production of IL-1beta and IL-6.

Conclusions: Our results indicate that chloroquine-mediated inhibition of TNF-alpha, IL-1beta and IL-6 synthesis occurs through different modes in lipopolysaccharide-stimulated human monocytes/macrophages: it blocks the conversion of cell-associated TNF-alpha precursor to mature soluble protein, whereas it reduces the levels of IL-1beta and IL-6 mRNA, at least in part, by decreasing their stability and by a pH-dependent mechanism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antirheumatic Agents / pharmacology*
  • Cells, Cultured
  • Chloroquine / pharmacology*
  • Cytokines / biosynthesis*
  • Cytokines / genetics
  • Dose-Response Relationship, Drug
  • Gene Expression Regulation / drug effects
  • Humans
  • Interleukin-1 / biosynthesis
  • Interleukin-1 / genetics
  • Interleukin-6 / biosynthesis
  • Interleukin-6 / genetics
  • Lipopolysaccharides / immunology
  • Macrophages / drug effects
  • Macrophages / immunology
  • Monocytes / drug effects*
  • Monocytes / immunology
  • RNA, Messenger / genetics
  • Reverse Transcriptase Polymerase Chain Reaction / methods
  • Tumor Cells, Cultured
  • Tumor Necrosis Factor-alpha / biosynthesis
  • Tumor Necrosis Factor-alpha / genetics


  • Antirheumatic Agents
  • Cytokines
  • Interleukin-1
  • Interleukin-6
  • Lipopolysaccharides
  • RNA, Messenger
  • Tumor Necrosis Factor-alpha
  • Chloroquine