A newly established murine immature dendritic cell line can be differentiated into a mature state, but exerts tolerogenic function upon maturation in the presence of glucocorticoid

Abstract

IntroductionImmature dendritic cells (DCs), specialized in the uptake of antigen, 1 reside as sentinels in almost every tissue. Under steadystate conditions, a small fraction of DCs acquire a semimature state and migrate to the draining secondary lymphoid organs. There, these semimature DCs exert tolerogenic functions by inducing apoptosis, anergy, or even a regulatory state in interacting autoreactive T cells that escaped elimination during negative thymic selection. In addition to natural regulatory T cells (Treg's), which originate in the thymus, induced Treg's, activated by tolerogenic DCs, are essential for maintainance of peripheral tolerance 2 and ensure tolerance to harmless environmental antigens. 3 In contrast, during infection, DCs engulf and process pathogenic material. Exposure to pathogen-derived molecules like lipopolysaccharide (LPS) or proinflammatory cytokines produced by cells in the microenvironment induces the full maturation of DCs, characterized by strong up-regulation of expression of costimulatory molecules and the production of proinflammatory cytokines. 4 Mature DCs constitute the most potent antigen-presenting cells, which are capable of stimulating naive antigen-specific T cells and thereby inducing a primary immune reaction.Several DC subsets with distinct phenotypes and functions have been identified. 5 In mice, CD11c has been acknowledged as a useful marker for DCs. DC subsets of myeloid origin (mDCs) mature in response to bacterial products and proinflammatory cytokines, and fully mature mDCs are inducers of strong immune responses. However, following treatment with anti-inflammatory cytokines (IL-10, transforming growth factor-␤ [TGF-␤]) or pharmacologic agents like dexamethasone (DEX) and vitamin D 3 , mDCs differentiate into a tolerogenic state. 6,7 Plasmacytoid DCs (pDCs) express markers like GR-1 and, in mice, B220, although a distinct lymphoid origin of pDCs is still a matter of debate. 8,9 pDCs have been ascribed a profound tolerogenic potential both under homeostatic conditions and even upon activation, mainly induced by DNA and RNA viruses. 10 DC functions are mainly studied using bone-marrow-derived DCs (BM-DCs) which are as potent as primary DCs isolated from spleen. 11 BM-DCs exhibit myeloid characteristics upon generation from progenitors in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF), whereas a major fraction displays a pDC-like phenotype when progenitors are cultivated with Flt3-L. 12 However, the generation of BM-DCs is time consuming, cultures may contain contaminating cell types, and BM-DCs display a heterogenous phenotype concerning the expression of major histocompatibility complex (MHC) II and costimulatory molecules, and therefore T-cell stimulatory capacity. 13 To circumvent these problems, several cell lines with DC-like characteristics have been derived either from long-term cultures of murine skin Langerhans cells 14,15 or spleen cell suspensions, 16 or by An Inside Blood analysis of this article appears at the front of this...

Nontransformed, GM-CSF–dependent macrophage lines are a unique model to study tissue macrophage functions

“…MPI cells are model cells of differentiated tissue macrophages prepared without genetic manipulation or oncogenic transformation and share a number of properties with alveolar macrophages. Using GM-CSF and M-CSF, DC lines have been established previously from mouse spleen (23,24). We compared one of them, the SP37A3 cells (24), to the MPI cells.…”

“…Using GM-CSF and M-CSF, DC lines have been established previously from mouse spleen (23,24). We compared one of them, the SP37A3 cells (24), to the MPI cells. Our analysis of the gene expression profiles, surface markers, and responses to innate stimuli showed that SP37A3 cells are quite different from MPI cells.…”

Glucocorticoid receptor translational isoforms underlie maturational stage-specific glucocorticoid sensitivities of dendritic cells in mice and humans

“…11,12,15 Consequently, glucocorticoids impair T-cell stimulatory capacity of DCs. 13,14,16,17 In addition, glucocorticoids may reduce the number of DCs via inhibiting DC migration and increasing DC apoptosis, 7,9,10,12,15,[18][19][20][21][22][23][24][25] although some other reports suggest that glucocorticoids do not induce DCs apoptosis. 13,16,26,27 It is not known whether different DC subsets have differential sensitivity to glucocorticoid-induced apoptosis.…”

Mast Cells Induce Migration of Dendritic Cells in a Murine Model of Acute Allergic Airway Disease

“…Bone marrow-derived DCs (BMDCs) were generated according to a previously published protocol [16]. Bone marrow cells were grown in culture medium (IMDM, 10% FCS, 50 µ M β-mercaptoethanol, 2 m M glutamine, 100 µg/ml streptomycin, 100 U/ml penicillin supplemented with 5% of granulocyte-monocyte colony-stimulating factor (GM-CSF)-containing cell culture supernatant derived from X63.Ag8–653 myeloma cells stably transfected with a murine GM-CSF expression construct, a kind gift from Dr. B. Stockinger, National Institute for Medical Research, London, UK).…”