GM‐CSF increases cross‐presentation and CD103 expression by mouse CD8⁺ spleen dendritic cells

Abstract

Resident CD8 1 DCs perform several functions, including cross-presenting antigen and rapidly engulfing the Gram-positive intracellular pathogen Listeria monocytogenes. Little is known about how these functions of CD8 1 DCs are modulated. Here, we show that granulocyte-macrophage CSF (GM-CSF), a cytokine that exists at low levels at steady state but is elevated during infection and inflammation, enhances cross-presentation and rapid uptake of L. monocytogenes by resident CD8 1 DCs. This previously unrecognized functional enhancement of CD8 1 DCs by GM-CSF was independent of promoting DC survival in vitro. Enhancement of these functions by GM-CSF was also marked by CD103 expression on CD8 1 DCs that was strongly regulated by GM-CSF. Our findings not only identify GM-CSF as a key molecule regulating CD8 1 DC function, but also as a factor responsible for functional heterogeneity of CD8 1 DCs that is at least substantially demarcated by CD103 expression.Keywords: CD8 1 DC . CD103 . Cross-presentation . Granulocyte-macrophage colony-stimulating factor . Listeria monocytogenes Supporting Information available online IntroductionDCs found in the spleen can be grossly separated into CD8 1 DCs and CD8 À DCs. The latter includes CD8 À CD4 1 and CD8 À CD4 À conventional DCs and CD45RA 1 plasmacytoid DCs. Different DC subsets have different functions. Notably, the resident CD8 1 DCs show superior capacity for ingesting cell-associated antigens [1], for cross-presenting antigens (i.e. presenting exogenous antigens to CD8 1 T cells) [2][3][4], for the rapid uptake of certain bacterial pathogens [5] and for producing . It has been previously reported that a small proportion of CD8 1 DCs express the integrin CD103 and these CD103-expressing CD8 1 DCs are enriched in cells engulfing cellular antigens and cross-priming CD8 1 T cells [7]. However, it is unclear what regulates the above à Co-senior authors. Here, we investigated whether GM-CSF might influence the function of CD8 1 DCs and CD103 expression. Functionally, DCs from GM-CSF transgenic (GMtg) mice had enhanced crosspresentation, whereas in the absence of GM-CSF signaling, crosspresentation was reduced. Rapid uptake of Listeria monocytogenes by CD8 1 DCs was also reduced in the absence of GM-CSF. Phenotypically, we showed that bacterial infection preferentially increased CD103 expression by CD8 1 DCs and this increase was dependent on GM-CSF. Together, our results identify a critical role for GM-CSF in preferentially regulating expression of the integrin CD103 by CD8 1 DCs and in regulating certain functions of CD8 1 DCs. ResultsGM-CSF enhances cross-presentation by CD8 1 DCs GM-CSF is a cytokine that exists at very low levels at steady state but is greatly induced during infection and inflammation [13]. To understand the role of GM-CSF in regulating the functions of CD8 1 DCs, we chose mouse models with GM-CSF overexpression. We first compared the cross-presentation by CD8 1 DCs from GMtg mice and control littermates. When soluble OVA was used as the antigen in vitro, CD...

Conventional Dendritic Cells Require IRAP-Rab14 Endosomes for Efficient Cross-Presentation

“…3C). We hypothesized that this could be due to the absence of GM-CSF in our Flt3L cultures, given that the ability of CD8 + DCs to cross-present has recently been shown to depend on GM-CSF (34,35). To analyze this possibility, we tested the crosspresentation ability of spleen DC subsets that are physiologically differentiated in the presence of both cytokines, Flt3L and GM-CSF.…”

Selective and efficient generation of functional Batf3-dependent CD103+ dendritic cells from mouse bone marrow

“…Crosspresentation was proposed to be promoted by GM-CSF or toll-like receptor (TLR) signaling. 30,39 Conversely, tumor cells can inhibit DC functions and render them tolerogenic. 40,41 We established a cross-presentation assay of irradiated B16-OVA melanoma cells.…”

Cytokine‐dependent regulation of dendritic cell differentiation in the splenic microenvironment

“…Under inflammatory conditions monocytes are able to differentiate into mature DCs through the recognition of PAMPs in conjunction with GM-CSF (Csf-2) [5,6]. GM-CSF has been implicated in the formation of inflammatory DCs in vivo [7], and was also shown to enhance CD103 expression and the ability of CD8α + DCs to cross-present antigens to CD8 + T cells [8][9][10].Besides the classification of DC subsets on the basis of surface phenotype and migratory abilities, there is evidence that the local organ-specific microenvironment also has distinct influences on DC function even in phenotypically similar DC subsets. At the level of transcriptional profiling this has been indicated by direct comparison of defined DC subsets from different lymphoid organs [11].…”