Human tolerogenic dendritic cells produce IL-35 in the absence of other IL-12 family members

Eur J Immunol. 2015 Jun;45(6):1736-47. doi: 10.1002/eji.201445217.


IL-35 is a cytokine of the IL-12 family, existing as a heterodimer of IL-12p35 and Ebi3. IL-35 has anti-inflammatory properties and is produced by regulatory T cells in humans and mice, where it is required for optimal suppression of immune responses. Distinct from other IL-12 cytokines, the expression of IL-35 has not been described in antigen-presenting cells. In view of the immune-regulatory properties of IL-35, we investigated the expression, regulation, and function of IL-12p35 and Ebi3 in human monocyte-derived dendritic cells and tolerogenic DCs (tolDCs). These tolDCs do not produce IL-12p70 or the homodimer IL-12p40. We demonstrate that tolDCs completely lack transcriptional expression of IL-12p40. However, tolDCs maintain mRNA expression of IL-12p35 and Ebi3. Using intracellular flow cytometry and Western blot analysis, we show that tolDCs produce Ebi3 and IL-12p35, and both can be enhanced upon stimulation with IFN-γ, LPS, or CD40L. tolDCs supernatants have the capacity to suppress T-cell activation. Using IL12A silencing, we demonstrate that IL-12p35 is required for tolDCs to reach their full suppressive potential. Taken together, our results indicate that tolDCs produce IL-35, providing an additional novel mechanism by which tolDCs elicit their tolerogenic potential.

Keywords: Dendritic cells; Human; IL-12/IL-35 axis; Tolerance.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigen-Presenting Cells / immunology
  • Antigen-Presenting Cells / metabolism
  • B7 Antigens / metabolism
  • B7-2 Antigen / metabolism
  • B7-H1 Antigen / metabolism
  • Dendritic Cells / drug effects
  • Dendritic Cells / immunology*
  • Dendritic Cells / metabolism*
  • Dexamethasone / pharmacology
  • Gene Expression
  • Humans
  • Immune Tolerance* / drug effects
  • Interleukin-12 / biosynthesis
  • Interleukin-12 Subunit p35 / genetics
  • Interleukin-12 Subunit p35 / metabolism
  • Interleukin-27 / genetics
  • Interleukin-27 / metabolism
  • Interleukins / biosynthesis*
  • Interleukins / genetics
  • Interleukins / metabolism
  • Lipopolysaccharides / immunology
  • Minor Histocompatibility Antigens
  • Phenotype


  • B7 Antigens
  • B7-2 Antigen
  • B7-H1 Antigen
  • EBI3 protein, human
  • Interleukin-12 Subunit p35
  • Interleukin-27
  • Interleukins
  • Lipopolysaccharides
  • Minor Histocompatibility Antigens
  • interleukin-35, human
  • Interleukin-12
  • Dexamethasone