Subsets of CD1c+ DCs: Dendritic Cell Versus Monocyte Lineage
Lukas Heger, Thomas P. Hofer, Venetia Bigley, I. Jolanda M. de Vries, Marc Dalod, Diana Dudziak, Loems Ziegler‐Heitbrock
Abstract
Currently three bona fide dendritic cell (DC) types are distinguished in human blood. Herein we focus on type 2 DCs (DC2s) and compare the three defining markers CD1c, CD172 and CD301. Using CD1c to define DC2s, a CD14+ and a CD14- subset can be detected. The CD14+ subset shares features with monocytes and this includes substantially higher expression levels for MAFB, S100A8/9, CD163 and Ficolin1. We review the current knowledge of these CD1c+ CD14+ cells as compared to the CD1c+ CD14- cells with respect to phenotype, function, transcriptomics and ontogeny. Here, we discuss informative mutations, which suggest that two populations have different developmental requirements. In addition, we cover subsets of CD11c+CD8- DC2s in the mouse, where CLEC12A+ESAMlow cells, as compared to the CLEC12A-ESAMhigh subset, also express higher levels of monocyte-associated markers lysozyme, CD14 and CD36. Finally, we summarize, for both man and mouse, the data on lower antigen presentation and higher cytokine production in the monocyte-marker expressing DC2 subset, which demonstrate that the DC2 subsets are also functionally distinct.