M2a Macrophage Activation State Markers
Click on one of the macrophage activation states shown in the buttons below to see the markers that are commonly used to identify each activated state or view a list of the common macrophage markers used for distinguishing macrophages from other immune cell types.
Overview
M2a Macrophage Activation State Markers Overview
Macrophages are activated following exposure to stimuli in their environments that direct their phenotypes and functions. The historical model of macrophage activation describes two different activation states, classical and alternatively activated macrophages. Whereas pro-inflammatory cytokines and microbial products stimulate classical M1 macrophage activation, which further promote inflammation, alternative macrophage activation is stimulated by IL-4 and IL-13 and leads to the generation of M2 macrophages with an anti-inflammatory phenotype. M2 macrophages have subsequently been categorized into different subtypes known as M2a, M2b, M2c, and M2d based on phenotypic variations noted in the M2 population following treatment with different activating stimuli. M2a macrophages secrete high levels of IL-10 and TGF-beta, along with other factors aimed at resolving inflammation and promoting wound repair and tissue remodeling. Common markers used to identify M2a macrophages include CD163, CD200 R1, MMR/CD206, low levels of MHC class II, and Arginase 1 (ARG1) in mouse. Additionally, FIZZ1 and YM1 are common mouse M2a macrophage markers, which lack human homologues.
Data Examples
Data Examples
Detection of Cell Surface Markers on Resting and M1 or M2a Activated Human Macrophages by Flow Cytometry. Enriched human CD14+ monocytes were cultured in the presence of 50 ng/mL Recombinant Human GM-CSF (R&D Systems, Catalog # 215-GM) or 50 ng/mL Recombinant Human M-CSF (R&D Systems, Catalog # 216-MC) for 6 days in a RPMI-based media containing 10% FBS. Following the 6-day maturation period, macrophages were activated for an additional 24 hours to either the classical M1 macrophage phenotype with 50 ng/mL lipopolysaccharide and 50 ng/mL Recombinant Human IFN-gamma (R&D Systems, Catalog # 285-IF; solid blue histograms) or alternatively activated M2a macrophage phenotype with 20 ng/mL Recombinant Human IL-4 and 20 ng/mL Recombinant Human IL-13 (R&D Systems, Catalog # 204-IL and Catalog # 213-ILB, respectively; solid purple histograms). Macrophages that were not activated were cultured for an additional 24 hours in media containing either GM-CSF (light blue histograms) or M-CSF (light purple histograms) so that all macrophages were cultured for a total of 7 days before being compared by flow cytometry. Cells were then stained with either a fluorochrome-conjugated Mouse Anti-Human CD200 R1 Monoclonal Antibody (R&D Systems, Catalog # FAB3414), a fluorochrome-conjugated Mouse Anti-Human CD163 Monoclonal Antibody (R&D Systems, Catalog # FAB1607), or a fluorochrome-conjugated Mouse Anti-Human DC-SIGN/CD209 Monoclonal Antibody (R&D Systems, Catalog # FAB161). Isotype control staining is indicated by the solid gray histograms. Zombie Violet™ cell viability dye labeling and doublet exclusion were used to remove dead cells from the surface marker expression analysis.