Related Experiment Video
Updated: Aug 9, 2026
Characterization of Human Monocyte-derived Dendritic Cells by Imaging Flow Cytometry: A Comparison between Two Monocyte Isolation Protocols
Published on: October 18, 2016
The involvement of CD14 in the activation of human monocytes by peptidoglycan monomers
D Muhvić1, V El-Samalouti, H D Flad
1Department of Physiology and Immunology, Medical Faculty, University of Rijeka, Croatia. damirm@mamed.medri
Background:
Cell-wall components of Gram-positive and Gram-negative bacteria induce the production of cytokines in human peripheral blood mononuclear cells. These cytokines are the main mediators of local or systemic inflammatory reaction that can contribute to the development of innate immunity.
Aims:
This study was performed to analyze the involvement of CD14 molecule in the activation of human monocytes by peptidoglycan monomer (PGM) obtained by biosynthesis from culture fluid of penicillin-treated Brevibacterium divaricatum NRLL-2311.
Methods:
Cytokine release of interleukin (IL)-1, IL-6 and tumor necrosis factor-alpha from human monocytes via soluble CD14 (sCD14) or membrane-associated (mCD14) receptor using anti-CD14 monoclonal antibody (MEM-18) or lipid A structure (compound 406) was measured in bioassays.
Results:
The results demonstrated that PGM in the presence of human serum might induce the monokine release in a dose-dependent manner. The addition of sCD14 at physiologic concentrations enhanced the PGM-induced monokine release, while the monokine inducing capacity of PGM in the presence of sCD14 was inhibited by MEM-18. Effects of PGM were also blocked by glycolipid, compound 406, suggesting the involvement of binding structures similar to those for lipopolysaccharide.
Conclusion:
Activation of human monocytes by PGM involves both forms of CD14 molecule, sCD14 and mCD14.
Insights
Peptidoglycan monomer (PGM) activates human monocytes through both soluble CD14 (sCD14) and membrane-associated CD14 (mCD14) receptors. This interaction is crucial for innate immunity and cytokine production.
Area of Science:
- Immunology
- Microbiology
- Biochemistry
Background:
- Bacterial cell-wall components, like peptidoglycan, trigger cytokine production in human immune cells.
- Cytokines mediate inflammatory responses, contributing to innate immunity.
Purpose of the Study:
- To investigate the role of the CD14 molecule in human monocyte activation by peptidoglycan monomer (PGM).
- To analyze PGM's interaction with both soluble (sCD14) and membrane-associated (mCD14) CD14 receptors.
Main Methods:
- Human monocytes were stimulated with PGM in the presence of human serum.
- Cytokine release (IL-1, IL-6, TNF-alpha) was measured using bioassays.
- The effects of sCD14, anti-CD14 antibody (MEM-18), and a lipid A analog (compound 406) were assessed.
Main Results:
- PGM induced dose-dependent monokine release in human serum.
- Physiological concentrations of sCD14 enhanced PGM-induced monokine release.
- Both MEM-18 and compound 406 inhibited PGM's effects, indicating CD14 receptor involvement and similarity to lipopolysaccharide binding.
Conclusions:
- Human monocyte activation by PGM involves both soluble (sCD14) and membrane-associated (mCD14) forms of the CD14 molecule.
- This pathway is significant for initiating inflammatory responses via bacterial components.
More Related Videos
11:48Isolation Protocol of Mouse Monocyte-derived Dendritic Cells and Their Subsequent In Vitro Activation with Tumor Immune Complexes
Published on: May 31, 2018
12:36Single-cell Analysis of Immunophenotype and Cytokine Production in Peripheral Whole Blood via Mass Cytometry
Published on: June 26, 2018
