Distinct Transcriptional Programs Control Cross-Priming in Classical and Monocyte-Derived Dendritic Cells

Area of Science:

• Immunology
• Cell Biology
• Dendritic Cell Biology

Background:

• Classical dendritic cells (cDCs) and monocyte-derived dendritic cells (Mo-DCs) both cross-prime CD8(+) T cells.
• Monocytes are a precursor population for Mo-DCs, influenced by cytokines like GM-CSF and IL-4.

Purpose of the Study:

• To investigate the distinct differentiation pathways of monocytes into Mo-DCs.
• To identify the key transcription factors required for Mo-DC differentiation and their capacity for T cell priming.

Main Methods:

• Monocyte subset analysis based on Ly-6C and TREML4 expression.
• Induction of Mo-DC differentiation using granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4).
• Assessment of Zbtb46 expression and T cell cross-priming ability.

Main Results:

• Ly-6C(hi)TREML4(-) monocytes differentiate into Zbtb46(+) Mo-DCs with GM-CSF and IL-4, requiring IRF4 and Batf3 induction.
• Ly-6C(hi)TREML4(+) monocytes are committed to a different lineage.
• IRF4 is essential for Mo-DC differentiation into Zbtb46(+) cells capable of cross-priming; BATF3 is not required, and its absence leads to macrophage differentiation.

Conclusions:

• Monocytes require distinct transcriptional programs (IRF4, not BATF3) to differentiate into Mo-DCs capable of cross-priming CD8(+) T cells.
• These findings highlight differences between cDCs and Mo-DCs in acquiring T cell priming capacity.
• Understanding these distinctions is crucial for developing Mo-DC-based therapeutic vaccines.