Expression of C‐type lectin receptors by subsets of dendritic cells in human skin

Abstract

C-type lectins are cell surface receptors that recognize carbohydrate structures which are often part of microbial pathogens. Several of these molecules are expressed on dendritic cells and are involved in antigen uptake. Expression of C-type lectins on dendritic cells of the human skin, i.e. Langerhans cells of the epidermis and dermal dendritic cells, has been incompletely studied to date. We therefore investigated C-type lectins in situ and on dendritic cells obtained by migration from skin explants by immunofluorescence and flow cytometry. Emphasis was laid on expression patterns of DEC-205/CD205 and BDCA-2, a marker for plasmacytoid dendritic cells. Langerhans cells in situ expressed low levels of DEC-205. Expression was upregulated upon maturation in skin explant organ culture. Most dermal dendritic cells were found to be positive for DEC-205 and DC-SIGN/CD209. Few BDCA-2-expressing cells were found in most skin samples. They were located in small groups in the dermis close beneath the basement membrane. The vast majority of all types of dendritic cells in normal human skin was of immature phenotype, i.e. did not express DC-LAMP/CD208. It is concluded that normal appearing human skin harbors different subsets of dendritic cells including few scattered BDCA-2-expressing cells, presumably plasmacytoid dendritic cells, expressing variable sets of C-type lectin receptors. This may critically contribute to the capacity of the skin immune system to flexibly respond to the world of microbial pathogens.

Normal human dermis contains distinct populations of CD11c+BDCA-1+ dendritic cells and CD163+FXIIIA+ macrophages

“…DC-LAMP/ CD208 is a lysosomal protein that specifically marks mature DCs (24). DEC-205/CD205 is a surface receptor that participates in DC antigen endocytosis; its expression increases during maturation, and it has been previously demonstrated in normal human skin (25). The low frequency of CD11c + DCs expressing these 2 antigens observed in normal skin is consistent with their expected immature DC status.…”

DC-SIGN Mediates Binding of Dendritic Cells to Authentic Pseudo-LewisY Glycolipids of Schistosoma mansoni Cercariae, the First Parasite-specific Ligand of DC-SIGN

“…Analysis of the glycolipids derived from ES products showed that they comprise species with Le X and pseudo-Le Y determinants. These ES products that enter the surrounding tissue are good candidate antigens to be encountered by surveying DCs, such as the DC-SIGN positive CD1a negative dermal DCs, which are found mostly in the upper dermis (35,49,50).…”

Syndecan-3 is a dendritic cell-specific attachment receptor for HIV-1

“…8A] . Therefore, these DCs mostly resemble the subepithelial and dermal DCs (17,19,20). We investigated the interaction of DCs with various HIV-1 strains, such as R5-tropic (NL4.3-BaL and JR-CSF), X4-tropic (NL4.3 and 92UG021.6), and gp120-deficient (NL4.3⌬Env) viruses.…”