Human CD1c (BDCA‐1)⁺ myeloid dendritic cells secrete IL‐10 and display an immuno‐regulatory phenotype and function in response to Escherichia coli

Abstract

+subsets that display unique gene expression profiles, suggesting specialized functions. CD1c+ DCs express TLR4 while CD141 + DCs do not, thus predicting that these two subsets have differential capacities to respond to Escherichia coli. We isolated highly purified CD1c + and CD141 + DCs and compared them to in vitro generated monocyte-derived DCs (MoDCs) following stimulation with whole E. coli. As expected, MoDCs produced high levels of the proinflammatory cytokines TNF, IL-6, and IL-12, were potent inducers of Th1 responses, and processed E. coli-derived Ag. In contrast, CD1c + DCs produced only low levels of TNF, IL-6, and IL-12 and instead produced high levels of the anti-inflammatory cytokine IL-10 and regulatory molecules IDO and soluble CD25. Moreover, E. coli-activated CD1c + DCs suppressed T-cell proliferation in an IL-10-dependent manner. Contrary to their mouse CD8 + DC counterparts, human CD141 + DCs did not phagocytose or process E. coli-derived Ag and failed to secrete cytokines in response to E. coli. These data demonstrate substantial differences in the nature of the response of human blood DC subsets to E. coli. Keywords: E. coli r Human dendritic cells r IL-10 See accompanying Commentary by Qian and CaoSupporting Information available online IntroductionDCs are potent antigen-presenting cells that play a fundamental role in the induction and regulation of innate and adaptiveCorrespondence: Dr. Kristen J. Radford e-mail: kradford@mmri.mater.org.au immune responses against microbial pathogens. DCs detect microbial products using a sophisticated repertoire of PRR that include the toll-like receptors (TLRs), nucleotide-binding oligomerization domain (NOD)-like receptors, retinoic acid * These authors contributed equally to this work.C 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.eji-journal.eu Eur. J. Immunol. 2012. 42: 1512-1522 Immunity to infection 1513 inducible gene 1 (RIG-I)-like receptors and C-type lectins. The nature of the immune response to a given pathogen is tightly regulated by the DC network, which consists of multiple subsets that are equipped with unique PRRs and are endowed with specialized functions. DCs in humans and mice can be categorized into three broad subtypes. These three subtypes are: (i) inflammatory DCs that are mobilized rapidly from monocytes in response to infection and inflammation (monocyte-derived DCs; MoDCs), (ii) migratory DCs that reside in the peripheral tissues and migrate to lymphoid tissues after encounter with Ag, and (iii) the blood and lymphoid tissue resident DCs that are comprised of plasmacytoid and myeloid DCs [1]. Further complexity arises within the steadystate myeloid DC subsets, which in humans are defined as lineage (CD3,14,15,19,20,56 ResultsMoDCs are the main DC subset responsive to E. coli CD1c + and CD141 + DCs were enriched from healthy donor leukapheresis products by immuno-magnetic selection, and flow sorted to high purity (>99%) using our established human DC isolation protocols [8,19]. Autologous MoDCs were differentiated from...

CMRF-56+blood dendritic cells loaded with mRNA induce effective antigen-specific cytotoxic T-lymphocyte responses

“…Expanded specific WT-1 126-134 ¡ T cells (Figs. 5 G-H) killed WT-1 126-134 , but not irrelevant KLK4 [11][12][13][14][15][16][17][18][19] peptide loaded T2 cells (Fig. 5I).…”

“…myeloid dendritic cells (mDC) can be subdivided into three populations: CD1c C , CD141 C (or XCR1 C ) and CD16 C mDC subsets. [12][13][14][15] Given the phenotypic and functional heterogeneity of BDC subsets, [16][17][18] it still remains unclear which might be best for therapeutic vaccination. The major myeloid CD1c C DC have been isolated clinically using a two-step immune selection technology, but these isolations take a long time and the low yields limit the DC vaccination dose.…”

Differential uptake and cross‐presentation of soluble and necrotic cell antigen by human DC subsets

“…CD1c + DCs and CD141 + DCs were isolated from PBMC by immuno-magnetic enrichment followed by flow sorting as previously described [13,30]. MoDCs were differentiated from CD14 + immuno-magnetically selected monocytes in the presence of GM-CSF and IL-4 as previously described [30].…”

Tolerogenic dendritic cells and their applications in transplantation

“…Escherichia coli-activated CD1c 1 DCs suppressed allogeneic T-cell proliferation via IL-10. 94 These CD1c 1 DCs were characterized by low levels of production of TNF-a, IL-6 and IL-12, but high levels of production of the anti-inflammatory cytokine IL-10, and expression of the regulatory molecules IDO and soluble CD25. DCs conditioned by total coumarins of Urtica dentata Hand, a traditional herbal medicine, were maturation-resistant and expressed much lower MHCII (IAk) and CD86.…”

“…Initial studies of DCs in human blood revealed that CD141 1 CD1c 1 DCs are equivalent to the mouse lymphoid resident CD8 1 DCs. 94 However, evidence for the immunosuppressive function of tol-DCs in humans has been limited to the use monocyte-derived DCs. Nevertheless, some achievements have been made in identifying the factors that modulate organspecific human DCs, as well as the underlying mechanisms for the negative regulation of the T-cell response by these tolerogenic cells.…”