Related Experiment Videos
CD14 is expressed by subsets of murine dendritic cells and upregulated by lipopolysaccharide
K Mahnke1, E Becher, P Ricciardi-Castagnoli
1Ludwig Boltzmann Institute for Cell Biology and Immunobiology of the Skin, Department of Dermatology, University of Münster, Germany.
Abstract:
The CD14 surface molecule is predominantly expressed by cells of myeloid origin and regarded as a specific marker for macrophages (M phi). Thus, in human mononuclear cell preparations, CD14 expression is a widely used parameter to distinguish M phi from dendritic cells (DC). Since a murine homologue of CD14 was recently identified, this study investigated expression of CD14 by murine M phi and DC. Flow cytometry with a monoclonal antibody directed against murine CD14 revealed that bone marrow-derived DC express CD14 to various extents during differentiation. Functionally, CD14high and CD14low DC did not differ significantly in their capacity to present alloantigen, protein antigen or immunogenic peptide. Furthermore, surface expression of CD14 could be modulated by interleukin (IL)-4 and LPS. Incubation of bone marrow-derived DC with IL-4 (100 U/ml) resulted in downregulation of CD14 surface expression, whereas exposure of BmDC to LPS (1 microgram/ml) led to upregulation of CD14. After blockage of CD14 molecules by incubation of DC with anti-CD14 antibodies, downregulation of LPS triggered IL-1 release could be detected. In addition, other M phi markers such as CD11b, F4/80, BM8, and ER-TR9, are also expressed on DC. Therefore, we conclude that CD14, like other M phi markers, is expressed on murine DC during maturation. Thus, M phi and DC cannot be distinguished by flow cytometry using these markers. Moreover, CD14 may be involved in mediating LPS-induced activation of murine DC.
Insights
CD14, a marker typically for macrophages (M phi), is also found on dendritic cells (DC) in mice. This finding challenges the use of CD14 for distinguishing M phi from DC in murine immune studies.
Area of Science:
- Immunology
- Cell Biology
Background:
- CD14 is a well-established marker for macrophages (M phi) in humans.
- Distinguishing M phi from dendritic cells (DC) in human samples often relies on CD14 expression.
- A murine CD14 homologue has been identified, prompting investigation into its expression on murine myeloid cells.
Purpose of the Study:
- To investigate the expression of CD14 on murine macrophages (M phi) and dendritic cells (DC).
- To determine if CD14 can be used to differentiate between murine M phi and DC.
- To explore the functional and regulatory aspects of CD14 expression on murine DC.
Main Methods:
- Flow cytometry using a monoclonal antibody against murine CD14.
- Analysis of CD14 expression on bone marrow-derived DC during differentiation.
- Functional assays assessing antigen presentation capacity of CD14high and CD14low DC.
- Modulation of CD14 expression using interleukin-4 (IL-4) and lipopolysaccharide (LPS).
- Investigation of IL-1 release after CD14 blockage.
Main Results:
- Murine bone marrow-derived DC express CD14 at varying levels during differentiation.
- CD14 expression on DC is modulated by IL-4 (downregulation) and LPS (upregulation).
- CD14high and CD14low DC exhibit similar antigen-presenting capabilities.
- Other M phi markers (CD11b, F4/80, BM8, ER-TR9) are also found on murine DC.
- Blockage of CD14 reduced LPS-induced IL-1 release from DC.
Conclusions:
- CD14 is expressed on murine dendritic cells (DC) during maturation, similar to other macrophage (M phi) markers.
- CD14 is not a reliable marker for distinguishing M phi from DC in mice using flow cytometry.
- CD14 may play a role in the activation of murine DC by LPS.