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Updated: May 26, 2026
Isolation, Characterization, and Purification of Macrophages from Tissues Affected by Obesity-related Inflammation
Published on: April 3, 2017
Expression of macrophage-selective markers in human and rodent adipocytes
Wael Khazen1, Jean-Pierre M'bika, Céline Tomkiewicz
1Institut National de la Santé et de la Recherche Médicale, Unit 530, Université Paris Descartes, Centre Universitaire des Saints-Pères, France.
Abstract:
CD14, CD68 and/or mouse F4/80 or human epidermal growth factor module-containing mucin-like receptor 1 (EMR1) are widely used as macrophage-specific markers. Since macrophages infiltrate several tissues during inflammatory processes, CD14, CD68 and EMR1-F4/80 have been employed to discriminate between tissue-containing macrophages, like adipose tissue (AT), and other cells. Using real-time PCR experiments, we show that isolated adipocytes from humans and mice AT express high levels of CD14 and CD68 mRNA, whereas EMR1-F4/80 is mainly present in the macrophage-containing stroma-vascular fraction. Furthermore, fibroblasts-like cells (adipoblasts), preadipocytes and adipocytes from the murine cell lines, 3T3-F442A and BFC-1, express CD14 and CD68 mRNA and protein as determined by fluorescence-activated cell sorter, but not F4/80 which, as expected, is strongly expressed in the macrophage cell line RAW264.7. These results reinforce the view that EMR1-F4/80 is the best macrophage marker to date and show that CD14 and CD68 are not macrophage-specific proteins.
Insights
CD14 and CD68 are not specific macrophage markers, as they are also found in adipocytes and preadipocytes. Mouse F4/80 (or human EMR1) remains the most reliable marker for identifying macrophages in various tissues.
Area of Science:
- Immunology
- Cell Biology
- Adipose Tissue Biology
Background:
- Macrophages infiltrate tissues during inflammation, making specific markers crucial for research.
- CD14, CD68, and F4/80 (or EMR1) are commonly used macrophage-specific markers.
- Distinguishing macrophages from other cells in tissues like adipose tissue (AT) is essential.
Purpose of the Study:
- To investigate the specificity of CD14, CD68, and F4/80 (EMR1) as macrophage markers.
- To determine the expression of these markers in adipocytes and other cells within adipose tissue.
- To validate the reliability of F4/80 (EMR1) versus CD14 and CD68.
Main Methods:
- Real-time PCR to analyze mRNA expression in isolated human and mouse adipocytes and stromal-vascular fractions.
- Fluorescence-activated cell sorting (FACS) to assess protein expression in murine cell lines (3T3-F442A, BFC-1) and a macrophage cell line (RAW264.7).
Main Results:
- Isolated human and mouse adipocytes express high levels of CD14 and CD68 mRNA.
- EMR1-F4/80 mRNA is primarily found in the macrophage-rich stromal-vascular fraction of adipose tissue.
- Murine adipocyte cell lines express CD14 and CD68 protein and mRNA, but not F4/80.
- RAW264.7 macrophage cell line strongly expresses F4/80.
Conclusions:
- CD14 and CD68 are not macrophage-specific proteins, as they are expressed by adipocytes and preadipocytes.
- Mouse F4/80 (human EMR1) is confirmed as a highly specific marker for macrophages.
- These findings necessitate a re-evaluation of CD14 and CD68 usage in studies involving adipose tissue and inflammation.
