Abstract
In human blood two monocyte populations can be distinguished, i.e., the CD14(++)CD16(-)DR(+) classical monocytes and the CD14(+)CD16(+)DR(++) proinflammatory monocytes that account for only 10% of all monocytes. We have studied TNF production in these two types of cells using three-color immunofluorescence and flow cytometry on whole peripheral blood samples stimulated with either LPS or with the bacterial lipopeptide S-(2,3-bis(palmitoyloxy)-(2-RS)-propyl)-N-palmitoyl-(R)-Cys-(S)-Ser-(S)-Lys(4)-OH,trihydrochloride (Pam3Cys). After stimulation with LPS the median fluorescence intensity for TNF protein was 3-fold higher in the proinflammatory monocytes when compared with the classical monocytes. After stimulation with Pam3Cys they almost exclusively responded showing 10-fold-higher levels of median fluorescence intensity for TNF protein. The median fluorescence intensity for Toll-like receptor 2 cell surface protein was found 2-fold higher on CD14(+)CD16(+)DR(++) monocytes, which may explain, in part, the higher Pam3Cys-induced TNF production by these cells. When analyzing secretion of TNF protein into the supernatant in PBMCs after depletion of CD16(+) monocytes we found a reduction of LPS-induced TNF by 28% but Pam3Cys-induced TNF was reduced by 64%. This indicates that the minor population of CD14(+)CD16(+) monocytes are major producers of TNF in human blood.
Publication types
- Research Support, Non-U.S. Gov't
MeSH terms
- Adjuvants, Immunologic / pharmacology
- Cells, Cultured
- Cysteine / analogs & derivatives*
- Cysteine / pharmacology
- Drosophila Proteins*
- Fluorescent Antibody Technique
- HLA-DR Antigens / biosynthesis*
- HLA-DR Antigens / blood
- Humans
- Immunomagnetic Separation
- Immunophenotyping
- Inflammation / immunology
- Inflammation / pathology
- Lipopolysaccharide Receptors / biosynthesis*
- Lipopolysaccharide Receptors / blood
- Lipopolysaccharides / pharmacology
- Lipoproteins / pharmacology
- Membrane Glycoproteins / biosynthesis
- Membrane Glycoproteins / genetics
- Monocytes / classification
- Monocytes / immunology*
- Monocytes / metabolism*
- RNA, Messenger / biosynthesis
- Receptors, Cell Surface / biosynthesis
- Receptors, Cell Surface / genetics
- Receptors, IgG / biosynthesis*
- Receptors, IgG / blood
- Receptors, Immunologic / metabolism
- Toll-Like Receptor 2
- Toll-Like Receptors
- Tumor Necrosis Factor-alpha / biosynthesis*
- Tumor Necrosis Factor-alpha / metabolism
Substances
- Adjuvants, Immunologic
- Drosophila Proteins
- HLA-DR Antigens
- Lipopolysaccharide Receptors
- Lipopolysaccharides
- Lipoproteins
- Membrane Glycoproteins
- RNA, Messenger
- Receptors, Cell Surface
- Receptors, IgG
- Receptors, Immunologic
- TLR2 protein, human
- Toll-Like Receptor 2
- Toll-Like Receptors
- Tumor Necrosis Factor-alpha
- 2,3-bis(palmitoyloxy)-2-propyl-1-palmitoylcysteine
- Cysteine