Immunophenotyping of M2 Macrophage Polarization
Often referred to as tumor associated macrophages (TAMs), M2 macrophages are more likely to express inhibitory ligands and secrete anti-inflammatory cytokines. M2 macrophages can inhibit NK Cell cytotoxicity by expressing non-classical MHC I molecules. Use this validated flow cytometry panel to phenotype M2 Macrophages.
Flow Cytometry Antibodies for Immunophenotyping of M2 Macrophages
| Marker | Clone | Fluorochrome | Catalog # |
| VEGF | 23410 | APC | IC2931A |
| SR-AI/MSR/CD204 | 351615 | PE | FAB2708P |
| CD163 | 215927 | PerCP | FAB1607C |
| MMR/CD206 | 685641 | Alexa Fluor®488 | FAB25342G |
| NCAM-1/CD56 | 2524C | Alexa Fluor®700 | FAB24086N |
| CD20 | 396444 | Alexa Fluor®405 | FAB4225V |
| CD3 | UCHT1* | Alexa Fluor®405 | FAB100V |
*Designate clones independently validated by HLDA.
Alexa Fluor® is registered trademark of Molecular Probes, Inc.
This multicolor flow cytometry panel was validated on human peripheral blood mononuclear cells (PBMCs).
Multicolor flow cytometry panel to identify M2 Macrophages. Monocytes were isolated from PBMCs via adherence depletion for 5 hours. Non-adherent cells were removed. Adherent cells were incubated for 6 days in C3 +10% huAB media with 50 ng/ml Recombinant Human M-CSF (Catalog # 216-MC), media and cytokines are refreshed on day 3.
For M2 polarization, 24 hours prior to staining, cells are incubated with 50 ng/ml human M-CSF (Catalog # 216-MC), 20 ng/ml Recombinant Human IL-4 (Catalog # 204-IL), and 20 ng/ml Recombinant Human IL-13 (Catalog # 213-ILB). Cells were stained with Anti-Human CD3 Alexa Fluor® 405, CD20 Alexa Fluor® 405, CD56 Alexa Fluor® 700, CD206 Alexa Fluor® 488, CD163 PerCP, CD204 PE, and VEGF APC. Cells were previously gated on Live CD3-CD20-CD56-.
Other Supplies Required
- PBS
- Flow Cytometry Staining Buffer (Catalog # FC001)
- Flow Cytometry Fixation Buffer (Catalog # FC004)
- -20 °C Methanol
- Fc-block (blocking IgG)
- (Optional) Isotype Control Antibodies
- 5 mL Flow cytometry tubes
Surface Stain
- Wash human PBMCs (1 x 106 cells per sample) with 2 mL of Staining Buffer (1X) (Catalog # FC001) or other BSA-containing buffer, by spinning at 300 x g for 5 minutes, using 5 mL flow cytometry tubes. Decant/aspirate supernatant.
- Fc-block cells with blocking IgG (1 μg IgG/106 cells) for 10 minutes at room temperature.
- Add previously titrated amount of each surface marker. Vortex tubes
- (Optional) To a separate tube, add 5 μL of each of the isotype control antibodies. Vortex tubes.
- Incubate the mixtures for 30-45 minutes at room temperature in the dark.
- At the end of the incubation, wash with 2 mL of Staining Buffer (1X), by spinning at 300 x g for 5 minutes. Decant/aspirate supernatant.
M2 Flow Cytometry Antibody Concentration Chart
| Marker | Fluorochrome | Recommended Concentration |
| NCAM1/CD56 | Alexa Fluor® 700 | 0.25-1 μg/106 cells |
| CD20 | Alexa Fluor® 405 | 5 μL/106 cells |
| CD3 | Alexa Fluor® 405 | 5 μL/106 cells |
| CD163 | PerCP | 10 μL/106 cells |
| MMR/CD206 | Alexa Fluor® 488 | 5 μL/106 cells |
Intracellular Stain (with alcohol permeabilization)
- Add 0.5 mL of cold Flow Cytometry Fixation Buffer (Catalog # FC004) and vortex. Incubate at room temperature for 10 minutes. Vortex cells intermittently in order to maintain a single cell suspension.
- Centrifuge cells 300-500 x g for 5 minutes. Decant the Fixation Buffer.
- Wash cells PBS (or HBSS) by adding 2 mL of PBS (or HBSS), centrifuge at 350-500 x g for 5 minutes, and decant buffer from pelleted cells. Repeat (2 total washes).
- Resuspend cells in 900 μL of -20 °C methanol. Incubate for 30 minutes at 4 °C.
- Centrifuge cells for 5 minutes at 350-500 x g. Remove and discard the supernatant. Wash 2 times with PBS (or HBSS) as described in step 1.
- Add previously titrated amount of conjugated antibody to intracellular activation markers. Vortex tubes.
- Wash cells 2 times with PBS (or HBSS) as described in step 3.
Note: If an unconjugated primary antibody is used, incubation with an appropriate secondary antibody should occur now. Dilute the secondary antibody in PBS (or HBSS), starting with the concentration suggested in the product datasheet. Incubate for 20-30 minutes in the dark and wash as in step 3. - Resuspend cell pellet in 200 - 400 μL of PBS for flow cytometric analysis.
M2 Flow Cytometry Antibody Concentration Chart
| Marker | Fluorochrome | Recommended Concentration |
| VEGF | APC | 10 μL/106 cells |
| SR-AI/MSR/CD204 | PE | 10 μL/106 cells |