Elsevier

Cellular Immunology

Volume 233, Issue 2, February 2005, Pages 148-157
Cellular Immunology

Dendritic cells acquire tolerogenic properties at the site of sterile granulomatous inflammation

https://doi.org/10.1016/j.cellimm.2005.04.007Get rights and content

Abstract

Subcutaneous implantation of polyvinyl sponges represents a suitable model for studying the mechanisms of acute and chronic inflammation, granulomatous foreign-body reaction, as well as wound healing. Using such a model in rats, we studied the phenotypic and functional characteristics of dendritic cells (DC). DC were purified from the sponge exudate using a combination of separation gradients, adherence to plastics, and immunomagnetic sorting. We have shown that the number of DC progressively increased in the sponges, reaching maximal values at day 10 after implantation, followed by their decrease thereafter. Inflammatory DC expressed MHC class II molecules and myeloid markers CD11b, CD11c, and CD68. A subset of DC expressed CD4, R-MC46, DEC-205, R-MC17, and CCR1. Compared to DC isolated in the early phase of inflammation (day 6 DC), DC in the late stage of inflammation (day 14 DC) had a lower capability to stimulate the proliferation of allogeneic lymphocytes and CD4+ T cells. This finding correlated with the downregulation of CD80, CD86, and CD54 expression and the increased proportion of plasmacytoid MHC class II+ His 24+ His 48+ DC. The suppression of allogeneic lymphocyte proliferation was abrogated by the treatment of DC with lipopolysaccharide. In addition, day 14 DC exerted tolerogenic capability in co-culture with allogenic CD4+ T cells. These results correlated with the increased levels of IL-10 and TGF-β in culture supernatants and the sponge exudate.

Introduction

Subcutaneous implantation of polyvinyl sponges represents a suitable experimental model for studying the pathways of inflammation and subsequent wound healing, triggered by tissue damage. In addition, prolonged persistence of the implanted sponges results in a foreign-body reaction followed by chronic granulomatous inflammation [1], [2].

The sequence of events after the tissue injury is initially characterized by activation of coagulation cascade and complement. Byproducts of these processes drive the development of chemotactic factors that recruit neutrophils, than monocytes and lastly T cells [3]. The majority of monocytes transform into macrophages, but about 25% of these cells differentiate into dendritic cells (DC)1[4]. As it is well known, DC are crucial antigen-presenting cells, promoting both immunity and tolerance [5], [6]. DC in peripheral tissue, such as Langerhans cells in epidermis and dermal (interstitial) DC, originate from their blood precursors or from monocytes [7]. They are functionally immature with limited capacity to activate naive T cells, but with high potential to capture and process antigens. Foreign antigens and inflammatory stimuli increase the recruitment of DC at the sites of inflammation and promote their migration towards regional lymph nodes, where final maturation of DC occurs [8].

Some experimental evidence suggests that DC at the inflammatory site recruit other inflammatory cells, modulate angiogenesis, and promote or suppress local T cell effector functions [9]. These mechanisms are of crucial importance for the regulation of inflammation and wound repair. In addition, DC can be involved in the pathogenesis of numerous chronic inflammatory diseases [10]. However, we are still at the beginning of understanding how DC perform these different functions.

In this study, we used a model of subcutaneous implantation of polyvinyl sponges in rats to study the phenotypic and functional characteristics of DC accumulated into the sponge exudate. Such experiments have not been performed so far. We found that, with the progression of granulomatous inflammation, DC acquire tolerogenic capacity. The relationship of this phenomenon with different DC subsets and cytokine production is discussed.

Section snippets

Animals

AO and DA rats, both sexes, 8–10 weeks old, bred at the Farm for Experimental Animals, Military Medical Academy, Belgrade, were used. AO rats were used in all experiments for the preparation of inflammatory DC, whereas lymph node lymphocytes or T cells of DA rats were used in allogeneic proliferation assays.

Antibodies

The following mouse anti-rat monoclonal antibodies (mAbs) (purified ascites) were used: OX-6 (anti-MHC class II—unconjugated and biotin conjugated), R73 (reactive with αβ-TCR), W3/25

Dynamics of change in the number of DC during inflammation

Inflammatory cells were isolated from implanted sponges at different time points. Cytospins were prepared and stained with OX-6 mAb reactive with rat MHC class II molecule. As presented in Fig. 1, both relative and absolute numbers of OX-6+ cells progressively increased in the inflammatory exudate, reaching maximal values at day 10 following implantation of the sponges. After that, their numbers decreased.

Most OX-6+ cells displayed a morphology characteristic for DC, and up to 20% of them

Discussion

In this work, we studied the dynamics of changes in number, phenotype and functions of inflammatory DC, using a model of subcutaneous implantation of polyvinyl sponges in rats. This model is suitable for studying the processes of acute inflammation and wound healing (early phase) and chronic granulomatous inflammation [1], [15]. To our knowledge, this is the first paper examining DC using such a model of the foreign body response.

We have shown that the number of DC isolated from the sponge

Acknowledgments

We thank Dr. H. Yagita (Jutendo University, Tokyo, Japan), Dr. C. Dijkstra (Free University, Amsterdam, The Netherlands) and Dr. Dammers (University of Groningen, The Netherlands) for generous gifts of 3H5, 2F4; 1B6c; His 24 and His 48 mAbs, respectively.

References (36)

  • J.A. Hamilton

    Nondisposable materials, chronic inflammation, and adjuvant action

    J. Leukoc. Biol.

    (2003)
  • J. Banchereau et al.

    Immunobiology of dendritic cells

    Annu. Rev. Immunol.

    (2000)
  • R.M. Steinman et al.

    Tolerogenic dendritic cells

    Annu. Rev. Immunol.

    (2003)
  • K. Shortman et al.

    Mouse and human dendritic cell subtypes

    Nat. Rev. Immunol.

    (2002)
  • K. Kikly et al.

    DC in wound healing

  • M. Colic et al.

    Immunohistochemical characterization of rat thymic non-lymphoid cells. I. Epithelial and mesenchymal components defined by monoclonal antibodies

    Immunology

    (1988)
  • M. Colic et al.

    Identification of molecules shared between subcapsular/medullary epithelium, granulocytes, and a set of macrophages in rat thymus

  • T. Brocker

    Survival of mature CD4 T lymphocytes is dependent on major histocompatibility complex class II-expressing dendritic cells

    J. Exp. Med.

    (1997)
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