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Chemokines are the main proinflammatory mediators in human monocytes activated by Staphylococcus aureus,

Z M Wang1, C Liu, R Dziarski

  • 1Northwest Center for Medical Education, Indiana University School of Medicine, Gary, Indiana 46408, USA.

The Journal of Biological Chemistry
|April 7, 2000
PubMed

Insights

Bacterial infections primarily activate chemokine genes, not commonly believed proinflammatory cytokines like TNF-alpha and IL-6. This study reveals chemokines are key mediators in host response to bacteria.

Area of Science:

  • Immunology
  • Molecular Biology
  • Bacterial Pathogenesis

Background:

  • Proinflammatory cytokines like TNF-alpha, IL-1, and IL-6 are traditionally considered primary mediators of bacterial infection response.
  • The specific gene expression patterns induced by bacterial components in human monocytes require further elucidation.

Purpose of the Study:

  • To investigate the gene expression profiles in human monocytes stimulated with bacterial components.
  • To compare the induction levels of chemokine and cytokine genes by bacterial stimuli.
  • To identify the primary mediators of the host response to bacterial infections.

Main Methods:

  • Human monocytes were stimulated with Staphylococcus aureus, peptidoglycan, and endotoxin.
  • Gene expression was analyzed using cDNA arrays, quantitative RNase protection assays, and enzyme-linked immunosorbent assays.
  • Interferon-gamma served as a non-bacterial control stimulus.

Main Results:

  • Bacterial stimulants induced over 120 genes, with chemokine genes (e.g., IL-8, MIP-1alpha) showing the highest induction.
  • Cytokine genes (TNF-alpha, IL-1, IL-6) were induced to a lesser extent compared to chemokines.
  • Each bacterial stimulus elicited a unique gene expression pattern, distinct from the non-bacterial stimulus.

Conclusions:

  • Chemokines, not commonly cited cytokines, are the principal mediators induced by both Gram-positive and Gram-negative bacteria.
  • These findings highlight the critical role of chemokines in the inflammatory response to bacterial infections.
  • The study provides a comprehensive view of the host's molecular response to bacterial components.

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