Mechanisms of allergy and clinical immunology
Human immature myeloid dendritic cells trigger a TH2-polarizing program via Jagged-1/Notch interaction

https://doi.org/10.1016/j.jaci.2008.01.004Get rights and content

Background

The mechanisms by which human dendritic cells (DCs) activate a TH1-polarizing or TH2-polarizing program are still partially unclear.

Objective

Study of the mechanisms responsible for the TH1/TH2-polarizing activity of human circulating myeloid DCs before and after ligation of their Toll-like receptors (TLRs).

Methods

IL-4 and IFN-γ production by CD4+ T cells was assessed in cocultures with myeloid DCs before or after TLR triggering. Expression of Jagged-1 and Delta-4 Notch ligands and of GATA-3 and T-box expressed in T cells transcription factors was evaluated by real-time quantitative PCR. Signal transducer and activator of transcription 4 and 6 phosphorylation was assessed by flow cytometry. Knockdown of Jagged-1 or Delta-4 was performed by transfection of DCs with appropriate silencing mRNAs.

Results

Myeloid immature DCs constitutively expressed Jagged-1, which induces in CD4+ T cells a TH2 polarization, as shown by Jagged-1 gene silencing. The TH2 polarization associated with high GATA-3/T-box expressed in T cells ratio and was at least partially dependent on the early induction of IL-4. Maturation of DCs by TLR ligation resulted in the reduction of Jagged-1 and upregulation of Delta-4, which was at least in part responsible for the polarization of CD4+ T cells to the TH1 phenotype.

Conclusion

CD4+ T-cell responses are usually characterized by a prevalent TH2 phenotype unless TLRs are triggered on DCs by microbial components.

Section snippets

Donors

Human PBMCs used in this study were obtained in accordance with the ethical standards of the responsible regional committee on human experimentation.

For reagents and antibodies, flow cytometry analysis, isolation of CD4+, CD14+, CD45RA+, CD45RO+ and BDCA-1+ cell, generation of DCs and of short term T-cell cultures, RNA isolation, cDNA synthesis and real-time quantitative RT-PCR, evaluation of TCR Vβ repertoire by spectratyping, Western blot analysis, siRNA delivery, and gene silencing, refer to

Culturing CD4+ T cells with myeloid iDCs results in the development of TH2-polarized cells

To understand the role of myeloid DCs on the process of TH1/TH2 polarization, we compared the cytokine production profile of CD4+ T-cells present in streptokinase-stimulated or Dermatophagoides pteronyssinus group 1 (Der p 1)–stimulated PBMCs of healthy nonatopic donors with that of CD4+ T cells stimulated with the same antigens in presence of autologous DCs obtained in vitro by culturing CD14+ cells with IL-4 plus GM-CSF. As shown in previous studies,16 after stimulation of whole PBMCs with

Discussion

Dendritic cells are a complex and heterogeneous family of cells that play an important role in the innate as well as the subsequent adaptive immune responses because they are capable of antigen uptake, processing, and presentation to T cells.20 At least 2 distinct pathways of DC development have been identified in mice, myeloid and lymphoid,21, 22 which differ in phenotype, localization, and function.21 In human beings, DCs represent 1% to 2% of PBMCs and are made up of at least 2 major subsets

References (34)

  • J. Riedler et al.

    Exposure to farming in early life and development of asthma and allergy: a cross-sectional survey

    Lancet

    (2001)
  • S. Romagnani

    Immunologic influences on allergy and the TH1/TH2 balance

    J Allergy Clin Immunol

    (2004)
  • J. Debarry et al.

    Acinetobacter lwoffi and Lactococcus lactis strains isolated from farm cowsheds possess strong allergy-protective properties

    J Allergy Clin Immunol

    (2007)
  • S. Romagnani

    Coming back to a missing immune deviation as main explanatory mechanism for the hygiene hypothesis

    J Allergy Clin Immunol

    (2007)
  • F. Annunziato et al.

    Reversal of human allergen-specific CRTH2+ TH2 cells by IL-12 or the PS-DSP30 oligodeoxynucleotide

    J Allergy Clin Immunol

    (2001)
  • T.R. Mosmann et al.

    TH1 and TH2 cells: different patterns of lymphokine secretion lead to different functional properties

    Annu Rev Immunol

    (1989)
  • S. Romagnani

    Lymphokine production by human T cells in disease states

    Annu Rev Immunol

    (1994)
  • Cited by (0)

    Supported by the Italian Ministry of Education (40%), the Italian Ministry of Health grant by Ente Cassa di Risparmio, Florence, Italy (AIDS Project), EU Projects SENS-IT-IV (FP6-LSBH-CT-2006-018861), INNOCHEM (FP6-LSHB-CT-2005-518167), Agenzia Spaziale Italiana MoMa (WP ref: 1B1241-X5), and the German Federal Ministry of Education and Research (BMBF): 0313066F, 0313068C01 and 01 GS 0413 (NGFN-2: SIPAGE).

    Disclosure of potential conflict of interest: The authors have declared that they have no conflict of interest.

    These authors contributed equally to this work.

    View full text