Subsets of CD1c⁺ DCs: Dendritic Cell Versus Monocyte Lineage.

Area of Science:

• Immunology
• Cell Biology

Background:

• Three bona fide dendritic cell (DC) types are recognized in human blood.
• Type 2 DCs (DC2s) are a key focus, defined by markers like CD1c, CD172, and CD301.
• CD1c+ DC2s can be further divided into CD14+ and CD14- subsets.

Purpose of the Study:

• To compare the CD1c+CD14+ and CD1c+CD14- DC2 subsets in humans.
• To investigate the phenotypic, functional, transcriptomic, and ontogenic differences between these subsets.
• To explore analogous DC2 subsets in mice and their functional distinctions.

Main Methods:

• Comparative analysis of DC2 subsets based on cell surface marker expression (CD1c, CD14, CD64, CD115, CD163, S100A8/9).
• Review of existing knowledge on phenotype, function, transcriptomics, and ontogeny.
• Examination of informative mutations and mouse DC2 subsets (CLEC12A, ESAM).

Main Results:

• The CD1c+CD14+ DC2 subset expresses higher levels of monocyte-associated markers (CD64, CD115, CD163, S100A8/9) compared to the CD1c+CD14- subset.
• Informative mutations suggest different developmental requirements for the two human DC2 subsets.
• Mouse DC2 subsets (CLEC12A+ESAMlow) also show higher monocyte marker expression (CD14, CD3, CD115).

Conclusions:

• Human and mouse DC2 subsets expressing monocyte markers are functionally distinct.
• These subsets exhibit lower antigen presentation and higher cytokine production.
• The findings highlight functional divergence within DC2 populations based on monocyte marker expression.