Hi Olivier,

Langerhans cells typically self-renew within the skin, so differentiation from blood- or BM-derived monocytes is not common in vivo. However they can be reconstituted from the blood if sufficiently depleted. FYI, there are Langerin+ dermal dendritic cells (they are BM-renewed) and they are NOT Langerhans cells. The two populations are actually dichotomous in some situations. For example, Langerhans cells suppress allergic contact dermatitis, dermal Langerin+ cells promote it. Langerhans cells skew T cell responses toward Th17, Langerin+ dermal dendritic cells toward Th1. In my opinion, if you start with monocytes, you're more likely to get the dermal cells. If this doesn't matter to you, then you can ignore everything I just said. I'm sorry, I don't have the cytokines for in vitro differentiation, but Langerhans cells are highly dependent on TGFb. One more thing - they're pretty easy to isolate out of skin, so maybe you don't need to differentiate them?

The addition of IL-4 prevents macrophage differentiation but can also inhibit Langerhan cell differentiation. Try with GM-CSF+TGFb +TNFa .

Hi Olivier,

Langerhans cells typically self-renew within the skin, so differentiation from blood- or BM-derived monocytes is not common in vivo. However they can be reconstituted from the blood if sufficiently depleted. FYI, there are Langerin+ dermal dendritic cells (they are BM-renewed) and they are NOT Langerhans cells. The two populations are actually dichotomous in some situations. For example, Langerhans cells suppress allergic contact dermatitis, dermal Langerin+ cells promote it. Langerhans cells skew T cell responses toward Th17, Langerin+ dermal dendritic cells toward Th1. In my opinion, if you start with monocytes, you're more likely to get the dermal cells. If this doesn't matter to you, then you can ignore everything I just said. I'm sorry, I don't have the cytokines for in vitro differentiation, but Langerhans cells are highly dependent on TGFb. One more thing - they're pretty easy to isolate out of skin, so maybe you don't need to differentiate them?

I would imagine that co-culturing them with a coated plate of dermal fibroblasts and TSLP would give you langerhan-like cells, I'm unsure if you have BMD monocytes or from the peripheral blood. In theory, I would think PBMC would be better to obtain circulating monocytes ready to infiltrate the skin; however, are those then langerhan cells?

I agree with John that isolating from the skin would be the best, there are perhaps mechanisms to expand them in the literature other than simply IL-4 and GM-CSF.

References:

http://www.jacionline.org/article/S0091-6749(07)00118-2/abstract

To obtain DC from PBMC the best cytokines are GM-CSF + IL-4. Although some researchers believe that IL-13+ GMCSF affect on DC difrentiation even more efficient than IL-4.

Many thanks for your rapid and pertinent answers.

I'm testing first the GMCSF+TGFB without IL-4 as suggested by Beatriz.

John, I agree with you that the best choice is the isolation of LC from skin but we need a simple and standardized method to obtain Langerhans-like cells (I also agree that thy are not really Langerhans cells described in the skin or other mucosae when obtrained from monocyte differentiation).

Morover, we need a lot of cells to study HIV/dendritc or Langerhans cells interactions in our systems.

Best regards

Olivier