IL-13 Is More Efficient than IL-4 for Recruiting Langerhans Cell Precursors from Peripheral CD14+ Monocytes
In: Exogenous dermatology: physical, chemical, biological, Volume 1, Issue 6, p. 279-289
ISSN: 1424-4624
<i>Background:</i> GM-CSF, IL-4 and TGF-β<sub>1</sub> can drive the differentiation of CD14+ monocytes towards the immature Langerhans (LC) dendritic cell (DC) pathway. Their in vivo epidermal LC counterparts are mainly identified by the langerin molecules which are cross-linked into Birbeck granules (BG) upon mannose residue activation. <i>Objective:</i> The IL-13 and IL-14 cytokines sharing similar anti-inflammatory/immune functions, we investigated whether IL-13 (plus GM-CSF/TGF-β<sub>1</sub>) can substitute for IL-4 to preferentially skew the CD14+ monocyte differentiation towards LC. <i>Methods:</i> CD14+ monocytes cultured in the presence of GM-CSF/TGF-β<sub>1</sub>/IL-13 (IL-13-DC) for 6 days were then compared to GM-CSF/TGF-β<sub>1</sub>/IL-4-generated LC (IL-4-DC) by studying their phenotype, ultrastructural and functional features. <i>Results:</i> IL-13, in synergy with GM-CSF/TGF-β<sub>1</sub>, induced CD14+ monocytes to differentiate into LC after a short TNF-α stimulation more efficiently than IL-4. IL-13-DC are more immature than IL- 4-DC, as shown by both their preserved expression of monocyte markers (CD14, CD68) and their strong capacity of FITC-dextran uptake. <i>Conclusion:</i> IL-13 in combination with GM-CSF/TGF-β<sub>1</sub>/TNF-α favors CD14+ monocyte differentiation into LC which display numerous BG.