Human plasmacytoid dendritic cells: from molecules to intercellular communication network

Abstract

Plasmacytoid dendritic cells (pDCs) are a specific subset of naturally occurring dendritic cells, that secrete large amounts of Type I interferon and play an important role in the immune response against viral infection. Several studies have highlighted that they are also effective antigen presenting cells, making them an interesting target for immunotherapy against cancer. However, the modes of action of pDCs are not restricted to antigen presentation and IFN secretion alone. In this review we will highlight a selection of cell surface proteins expressed by human pDCs that may facilitate communication with other immune cells, and we will discuss the implications of these molecules for pDC-driven immune responses.

Keywords: T lymphocytes; cross talk; pDC migration; surface markers; viral infection.

Figure 1

Plasmacytoid dendritic cell have the capacity to interact with various immune cells through an array of surface molecules. The expressed surface molecules of each cell type are divided into confirmed and potential interactions. The “confirmed” molecules have been reported to have a functional effect. Molecules listed in the “potential” column are molecules that have been found on human pDC but without functional data reported in literature. Molecules playing a potential role in humans, but already confirmed with functional studies in mouse are depicted in red.

Figure 2

Ligand/receptor paring of a pDC with an endothelial cell and the maturation state/activation stimuli associated with ligand or receptor expression on the pDC surface.

Figure 3

Ligand/receptor paring of a pDC with a T cell and the maturation state/activation stimuli associated with ligand or receptor expression on the pDC surface.

Figure 4

Ligand/receptor paring of a pDC with an iNKT cell and the maturation state/activation stimuli associated with ligand or receptor expression on the pDC surface.

Figure 5

Ligand/receptor paring of a pDC with a B cell and the maturation state/activation stimuli associated with ligand or receptor expression on the pDC surface.

Figure 6

Ligand/receptor paring of a pDC with a mDC and the maturation state/activation stimuli associated with ligand or receptor expression on the pDC surface.

Figure 7

Ligand/receptor paring of a pDC with an NK cell and the maturation state/activation stimuli associated with ligand or receptor expression on the pDC surface.

Figure 8

Direct cell interaction dependent on GITR/GITRL or CD40/CD40L binding and their effect on a certain cell type.

Figure 9

Ligand/receptor paring of a pDC with a tumor cell and the maturation state/activation stimuli associated with ligand or receptor expression on the pDC surface.