It's not specific for DCs, but regulatory DCs produce IDO (indoleamine-dioxygenase) which is inhibitory for T cell functions, including proliferation and survival. However, it is not a surface marker, it is an intracellular enzyme, and it is present in mature plasmacytoid DCs (pDCs). Thus, I suggest you to look for pDC markers, such as CD123, lack of CD11c, and associate these markers with pDC functions, such as type IFN secretion, IDO expression and T cell inhibition.

Joao is right; IDO is a good marker of regulatory DC but not a surface marker and would need to be detected by ELISA for the protein or real-time PCR for the mRNA. Looking at pDC markers are not a clear indicator of regulatory DC because if you are looking at responses to virsuses or vrial agonists then you would want to Type1 IFN as a proinflammatory read-out. CD123 is a pDC-specific marker and CD11c expression is instrinic to murine DC.

Markers to look at are signalling lymphocyte activation molecule (SLAM), programmed cell death ligand (PDL)-1 and -2 synonymous with B7-H1 or B7-DC, DEC-205 (CD205) and immunoglobulin-like transcript (ILT) family (ILT3/ILT4). Also do a compartive analysis of CD80 and CD86 expression in your populations... CD80 binds preferentially to CTLA-4 and with higher affinity than CD86.

Nicolas, I agree with Anthony. You want defintiely look at SLAM, PDL1 and 2 and other markers he lists. I also agree with CD80/86; however, in our models they coudl be simply diminished to induce more "tolerizing" response.

You could also perform intracellular stain for some "regulatory cytokines" and/or look by PCR for expression of some tolerance-related genes in mRNA.

Good Luck!

You can measure RALDH activity by Aldefluor. Many tolerogenic DCs express CD103.

I agree with you all here, but none of the markers mentioned above are surface specific for regulatory DCs. Also, there are a number of co-inhibitory and co-stimulatory molecules that I didn't mentioned because they're an overwhelming amount of information, but just in case you want to research a little bit more, there are some good reviews on this subject available: "Molecular mechanisms of T cell co-stimulation and co-inhibition, Chen & Flies, Nat Rev Immunol, 2013"; "Tolerogenic Dendritic Cells, Steinman & Nussenzweig, Ann Rev Immunol, 2003"; CD83 could also be tested, in this context: "Local secretion/shedding of tumor-derived CD83 molecules as a novel tumor escape mechanism, Baleeiro & Barbuto, Mol Immunol, 2008" and "Expression of DC maturation marker CD83 on tumor cells from lung cancer patients (...), Cancer Immunol Immunother, 2007.

Personally, I believe that regulatory DC are not a rigid DC subset but more an activation feature hence why there aren't exclusive surface markers. But despite this, reg DC, no matter their origin or subset, they have common characteristics.

CD83 is a human DC marker. I've never managed to detect it on BMDC.

Below is a list of good markers for mouse dendritic cells

CD11c

CD123

CD83

CCR7 (CD197)

CD80

CD83

CD86

CD123 (IL-3Rα)

CD205

CD207 (Langerin)

CD209

CD273

CD283 (TLR3)

CD289 (TLR9)

CXCR4 (CD184)

IL-23 p19

MHC Class I

MHC Class II

Best Regards

Sibtain

Thanks to all!!! I will look at the expression pattern of IDO, CD11c, low co-stimulatory molecules such as CD86 and CD80, high production of IL10 and low IL12, PD-L1 and SLAM.

Actually, dear Anthony Huggins, as I mentioned above, CD83 is not a specific DC marker, it may be used by tumors also. And if we consider CD83 as a maturation marker, it shouldn't be found in BMDCs, because they are supposed to be more immature, right? Or am I mixing up things? Thank you all too.

About mouse CD83: "Description: The Michel-17 monoclonal antibody reacts with mouse CD83, a 45kDa cell surface glycoprotein and a member of the Ig superfamily. The mouse CD83 antigen is expressed predominantly on mature DC and activated lymphocytes. Cross-linking of CD83 with Michel-17 on DC or activated T cells does not induce any activation signal. CD83 plays an important role in T cell development through interaction with its ligand. CD83-Ig protein has revealed the presence of a CD83 ligand expressed mainly by B220+ cells in mouse spleen." @ http://www.ebioscience.com/mouse-cd83-antibody-purified-michel-17.htm

I'm seeking those markers in these days.. I think that IDO gene marker and IL-10 cytokine secretion are controversial. In the present, the Treg cell expansion by tolerogenic DC is available, when tDC is co-cultured with naive T cells.