Biochemical and functional characterization of three activated macrophage populations

• Published in: Journal of leukocyte biology Vol. 80; no. 6; pp. 1298 - 1307
• Main Authors: Edwards, Justin P., Zhang, Xia, Frauwirth, Kenneth A., Mosser, David M.
• Format: Journal Article
• Language: English
• Published: United States Society for Leukocyte Biology 01.12.2006
• Subjects: Animals; Arginase - biosynthesis; Arginase - immunology; B7-2 Antigen - immunology; Cell Proliferation - drug effects; Cells, Cultured; Coculture Techniques; Cytokines - biosynthesis; Cytokines - immunology; Cytokines - pharmacology; IL‐10; IL‐12; Intercellular Signaling Peptides and Proteins; LIGHT; Lipopolysaccharides - pharmacology; Macrophage Activation - drug effects; Macrophage Activation - immunology; Macrophages - classification; Macrophages - enzymology; Macrophages - immunology; Mice; Mice, Inbred BALB C; Nerve Growth Factor - biosynthesis; Nerve Growth Factor - immunology; Nitric Oxide - biosynthesis; Nitric Oxide - immunology; Phosphotransferases (Alcohol Group Acceptor) - biosynthesis; Phosphotransferases (Alcohol Group Acceptor) - immunology; Proteins - immunology; sphingosine kinase; Th1 Cells - immunology; Th2 Cells - immunology; Tumor Necrosis Factor Ligand Superfamily Member 14 - biosynthesis; Tumor Necrosis Factor Ligand Superfamily Member 14 - immunology
• ISSN: 0741-5400; 1938-3673
• DOI: 10.1189/jlb.0406249

We generated three populations of macrophages (Mφ) in vitro and characterized each. Classically activated Mφ (Ca‐Mφ) were primed with IFN‐γ and stimulated with LPS. Type II‐activated Mφ (Mφ‐II) were similarly primed but stimulated with LPS plus immune complexes. Alternatively activated Mφ (AA‐Mφ) were primed overnight with IL‐4. Here, we present a side‐by‐side comparison of the three cell types. We focus primarily on differences between Mφ‐II and AA‐Mφ, as both have been classified as M2 Mφ, distinct from Ca‐Mφ. We show that Mφ‐II more closely resemble Ca‐Mφ than they are to AA‐Mφ. Mφ‐II and Ca‐Mφ, but not AA‐Mφ, produce high levels of NO and have low arginase activity. AA‐Mφ express FIZZ1, whereas neither Mφ‐II nor Ca‐Mφ do. Mφ‐II and Ca‐Mφ express relatively high levels of CD86, whereas AA‐Mφ are virtually devoid of this costimulatory molecule. Ca‐Mφ and Mφ‐II are efficient APC, whereas AA‐Mφ fail to stimulate efficient T cell proliferation. The differences between Ca‐Mφ and Mφ‐II are more subtle. Ca‐Mφ produce IL‐12 and give rise to Th1 cells, whereas Mφ‐II produce high levels of IL‐10 and thus, give rise to Th2 cells secreting IL‐4 and IL‐10. Mφ‐II express two markers that may be used to identify them in tissue. These are sphingosine kinase‐1 and LIGHT (TNF superfamily 14). Thus, Ca‐Mφ, Mφ‐II, and AA‐Mφ represent three populations of cells with different biological functions.