scholarly journals Antigen-pulsed dendritic cells can efficiently induce an antibody response in vivo.

1992 ◽  
Vol 175 (1) ◽  
pp. 15-21 ◽  
Author(s):  
T Sornasse ◽  
V Flamand ◽  
G De Becker ◽  
H Bazin ◽  
F Tielemans ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Antibody Response ◽  
Interleukin 2 ◽  
Humoral Response ◽  
T Helper ◽  
Pulsed Dc ◽  
Immunization Procedure

The aim of this study was to develop an immunization procedure avoiding external adjuvant. Data are presented showing that syngeneic dendritic cells (DC), which have been pulsed in vitro with antigen, induce a strong antibody response in mice. By contrast, antigen (Ag)-pulsed low-density B cells, although equally able to induce interleukin 2 secretion by an Ag-specific T cell hybridoma in vitro, only weakly prime the mice in vivo. Moreover, we show that the injection of Ag-pulsed DC induces the synthesis of isotypes similar to the immunoglobulin classes detected after immunization with the same Ag in complete Freund's adjuvant. Importantly, high amounts of IgG2a antibodies are produced, suggesting that T helper type 1 cells are activated. Collectively, these data indicate that DC can initiate a primary humoral response and that they may be used as physiological adjuvant in vivo.

scholarly journals Dendritic Cells Discriminate between Yeasts and Hyphae of the Fungus Candida albicans

2000 ◽  
Vol 191 (10) ◽  
pp. 1661-1674 ◽  
Author(s):  
Cristiana Fè d'Ostiani ◽  
Giuseppe Del Sero ◽  
Angela Bacci ◽  
Claudia Montagnoli ◽  
Antonio Spreca ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Candida Albicans ◽  
Ex Vivo ◽  
T Helper ◽  
Myeloid Dendritic Cells ◽  
Mucosal Surfaces ◽  
A Cell

The fungus Candida albicans behaves as a commensal as well as a true pathogen of areas highly enriched in dendritic cells, such as skin and mucosal surfaces. The ability of the fungus to reversibly switch between unicellular yeast to filamentous forms is thought to be important for virulence. However, whether it is the yeast or the hyphal form that is responsible for pathogenicity is still a matter of debate. Here we show the interaction, and consequences, of different forms of C. albicans with dendritic cells. Immature myeloid dendritic cells rapidly and efficiently phagocytosed both yeasts and hyphae of the fungus. Phagocytosis occurred through different phagocytic morphologies and receptors, resulting in phagosome formation. However, hyphae escaped the phagosome and were found lying free in the cytoplasm of the cells. In vitro, ingestion of yeasts activated dendritic cells for interleukin (IL)-12 production and priming of T helper type 1 (Th1) cells, whereas ingestion of hyphae inhibited IL-12 and Th1 priming, and induced IL-4 production. In vivo, generation of antifungal protective immunity was induced upon injection of dendritic cells ex vivo pulsed with Candida yeasts but not hyphae. The immunization capacity of yeast-pulsed dendritic cells was lost in the absence of IL-12, whereas that of hypha-pulsed dendritic cells was gained in the absence of IL-4. These results indicate that dendritic cells fulfill the requirement of a cell uniquely capable of sensing the two forms of C. albicans in terms of type of immune responses elicited. By the discriminative production of IL-12 and IL-4 in response to the nonvirulent and virulent forms of the fungus, dendritic cells appear to meet the challenge of Th priming and education in C. albicans saprophytism and infections.

scholarly journals In Vivo Role of Dendritic Cells in a Murine Model of Pulmonary Cryptococcosis

2006 ◽  
Vol 74 (7) ◽  
pp. 3817-3824 ◽  
Author(s):  
Karen L. Wozniak ◽  
Jatin M. Vyas ◽  
Stuart M. Levitz
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Ex Vivo ◽  
Interleukin 2 ◽  
Mouse Lung

ABSTRACT Dendritic cells (DC) have been shown to phagocytose and kill Cryptococcus neoformans in vitro and are believed to be important for inducing protective immunity against this organism. Exposure to C. neoformans occurs mainly by inhalation, and in this study we examined the in vivo interactions of C. neoformans with DC in the lung. Fluorescently labeled live C. neoformans and heat-killed C. neoformans were administered intranasally to C57BL/6 mice. At specific times postinoculation, mice were sacrificed, and lungs were removed. Single-cell suspensions of lung cells were prepared, stained, and analyzed by microscopy and flow cytometry. Within 2 h postinoculation, fluorescently labeled C. neoformans had been internalized by DC, macrophages, and neutrophils in the mouse lung. Additionally, lung DC from mice infected for 7 days showed increased expression of the maturation markers CD80, CD86, and major histocompatibility complex class II. Finally, ex vivo incubation of lung DC from infected mice with Cryptococcus-specific T cells resulted in increased interleukin-2 production compared to the production by DC from naïve mice, suggesting that there was antigen-specific T-cell activation. This study demonstrated that DC in the lung are capable of phagocytosing Cryptococcus in vivo and presenting antigen to C. neoformans-specific T cells ex vivo, suggesting that these cells have roles in innate and adaptive pulmonary defenses against cryptococcosis.

scholarly journals Selective Expression and Functions of Interleukin 18 Receptor on T Helper (Th) Type 1 but not Th2 Cells

1998 ◽  
Vol 188 (8) ◽  
pp. 1485-1492 ◽  
Author(s):  
Damo Xu ◽  
Woon Ling Chan ◽  
Bernard P. Leung ◽  
David Hunter ◽  
Kerstin Schulz ◽  
...  
Keyword(s):  
Th2 Cells ◽  
Interleukin 18 ◽  
T Helper ◽  
Th2 Cell ◽  
A Cell ◽  
Ifn Γ

Interleukin (IL)-18 induces interferon (IFN)-γ synthesis and synergizes with IL-12 in T helper type 1 (Th1) but not Th2 cell development. We report here that IL-18 receptor (IL-18R) is selectively expressed on murine Th1 but not Th2 cells. IL-18R mRNA was expressed constitutively and consistently in long-term cultured clones, as well as on newly polarized Th1 but not Th2 cells. IL-18 sustained the expression of IL-12Rβ2 mRNA, indicating that IL-18R transmits signals that maintain Th1 development through the IL-12R complex. In turn, IL-12 upregulated IL-18R mRNA. Antibody against an IL-18R–derived peptide bound Th1 but not Th2 clones. It also labeled polarized Th1 but not Th2 cells derived from naive ovalbumin–T cell antigen receptor-αβ transgenic mice (D011.10). Anti–IL-18R antibody inhibited IL-18– induced IFN-γ production by Th1 clones in vitro. In vivo, anti–IL-18R antibody reduced local inflammation and lipopolysaccharide-induced mortality in mice. This was accompanied by shifting the balance from Th1 to Th2 responses, manifest as decreased IFN-γ and proinflammatory cytokine production and increased IL-4 and IL-5 synthesis. Therefore, these data provide a direct mechanism for the selective effect of IL-18 on Th1 but not Th2 cells. They also show that the synergistic effect of IL-12 and IL-18 on Th1 development may be due to the reciprocal upregulation of their receptors. Furthermore, IL-18R is a cell surface marker distinguishing Th1 from Th2 cells and may be a therapeutic target.

Inhibitors of γ-secretase block in vivo and in vitro T helper type 1 polarization by preventing Notch upregulation of Tbx21

2005 ◽  
Vol 6 (7) ◽  
pp. 680-688 ◽  
Author(s):  
Lisa M Minter ◽  
Danielle M Turley ◽  
Pritam Das ◽  
Hyun Mu Shin ◽  
Ila Joshi ◽  
...  
Keyword(s):  
T Helper ◽  
Helper Type

scholarly journals The injection of deaggregated gamma globulins in adult mice induces antigen-specific unresponsiveness of T helper type 1 but not type 2 lymphocytes.

1992 ◽  
Vol 175 (1) ◽  
pp. 9-14 ◽  
Author(s):  
D De Wit ◽  
M Van Mechelen ◽  
M Ryelandt ◽  
A C Figueiredo ◽  
D Abramowicz ◽  
...  
Keyword(s):  
T Cells ◽  
Tolerance Induction ◽  
T Helper ◽  
Ifn Gamma ◽  
Specific Antibody Response ◽  
Adult Mice ◽  
Helper Type

Injection of adult mice with high doses of monomeric human gamma globulins (dHGG) has been previously shown to produce a state of peripheral tolerance in both B and T cells. To gain insight into the mechanism of induction and maintenance of adult tolerance in this model, we have analyzed the pattern of lymphokines produced by control and tolerant animals in response to the tolerogen. The data presented indicate that HGG-specific, interleukin 2 (IL-2)- and interferon gamma (IFN-gamma)-producing T cells (thus referred to as T helper type 1 [Th1] cells) are rendered unresponsive after in vivo administration of soluble HGG. In contrast, antigenic stimulation of T cells isolated from tolerant adult mice leads to increased production of IL-4 in vitro. In vivo challenge of dHGG-treated adult animals with hapten-coupled HGG (p-azophenylarsonate [ARS]-HGG) induced a significant ARS-specific antibody response, suggesting that tolerance induction in this model does not completely abrogate tolerogen-specific Th activity in vivo. In agreement with the in vitro data, hapten-specific antibody response of tolerant animals is characterized by a selective deficiency in the IFN-gamma-dependent IgG2a subclass. Injection of immunogenic forms of HGG into tolerant animals also produced an IL-4-dependent increase in total serum IgE levels, indicative of an increased activity of HGG-specific Th2 cells in these animals. The finding that tolerance induction differentially affects Th subpopulations suggests that crossregulation among lymphocyte subsets may play a role in the induction and/or maintenance of acquired tolerance in adults.

scholarly journals Neem Leaf Glycoprotein Partially Rectifies Suppressed Dendritic Cell Functions and Associated T Cell Efficacy in Patients with Stage IIIB Cervical Cancer

2011 ◽  
Vol 18 (4) ◽  
pp. 571-579 ◽  
Author(s):  
Soumyabrata Roy ◽  
Shyamal Goswami ◽  
Anamika Bose ◽  
Krishnendu Chakraborty ◽  
Smarajit Pal ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Dendritic Cells ◽  
T Cell ◽  
Ex Vivo ◽  
Stage Iiib ◽  
Immune Functions ◽  
Cell Functions

ABSTRACTMyeloid-derived dendritic cells (DCs) generated from monocytes obtained from stage IIIB cervical cancer (CaCx IIIB) patients show dysfunctional maturation; thus, antitumor T cell functions are dysregulated. In an objective to optimize these dysregulated immune functions, the present study is focused on the ability of neem leaf glycoprotein (NLGP), a nontoxic preparation of the neem leaf, to induce optimum maturation of dendritic cells from CaCx IIIB patients.In vitroNLGP treatment of immature DCs (iDCs) obtained from CaCx IIIB patients results in upregulated expression of various cell surface markers (CD40, CD83, CD80, CD86, and HLA-ABC), which indicates DC maturation. Consequently, NLGP-matured DCs displayed balanced cytokine secretions, with type 1 bias and noteworthy functional properties. These DCs displayed substantial T cell allostimulatory capacity and promoted the generation of cytotoxic T lymphocytes (CTLs). Although NLGP-matured DCs derived from CaCx monocytes are generally subdued compared to those with a healthy monocyte origin, considerable revival of the suppressed DC-based immune functions is notedin vitroat a fairly advanced stage of CaCx, and thus, further exploration ofex vivoandin vivoDC-based vaccines is proposed. Moreover, the DC maturating efficacy of NLGP might be much more effective in the earlier stages of CaCx, where the extent of immune dysregulation is less and, thus, the scope of further investigation may be explored.

scholarly journals CD4+ CD25+ Regulatory T Cells Control T Helper Cell Type 1 Responses to Foreign Antigens Induced by Mature Dendritic Cells In Vivo

2003 ◽  
Vol 198 (2) ◽  
pp. 259-266 ◽  
Author(s):  
Guillaume Oldenhove ◽  
Magali de Heusch ◽  
Georgette Urbain-Vansanten ◽  
Jacques Urbain ◽  
Charlie Maliszewski ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Peripheral Tolerance ◽  
T Helper Cell ◽  
Helper Cell ◽  
T Helper

Recent evidence suggests that in addition to their well known stimulatory properties, dendritic cells (DCs) may play a major role in peripheral tolerance. It is still unclear whether a distinct subtype or activation status of DC exists that promotes the differentiation of suppressor rather than effector T cells from naive precursors. In this work, we tested whether the naturally occurring CD4+ CD25+ regulatory T cells (Treg) may control immune responses induced by DCs in vivo. We characterized the immune response induced by adoptive transfer of antigen-pulsed mature DCs into mice depleted or not of CD25+ cells. We found that the development of major histocompatibility complex class I and II–restricted interferon γ–producing cells was consistently enhanced in the absence of Treg. By contrast, T helper cell (Th)2 priming was down-regulated in the same conditions. This regulation was independent of interleukin 10 production by DCs. Of note, splenic DCs incubated in vitro with Toll-like receptor ligands (lipopolysaccharide or CpG) activated immune responses that remained sensitive to Treg function. Our data further show that mature DCs induced higher cytotoxic activity in CD25-depleted recipients as compared with untreated hosts. We conclude that Treg naturally exert a negative feedback mechanism on Th1-type responses induced by mature DCs in vivo.

scholarly journals ITAM signaling in dendritic cells controls T helper cell priming by regulating MHC class II recycling

Blood ◽  
2010 ◽  
Vol 116 (17) ◽  
pp. 3208-3218 ◽  
Author(s):  
Daniel B. Graham ◽  
Holly M. Akilesh ◽  
Grzegorz B. Gmyrek ◽  
Laura Piccio ◽  
Susan Gilfillan ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Mhc Class Ii ◽  
Autoimmune Encephalitis ◽  
Class Ii ◽  
T Helper Cell ◽  
Helper Cell ◽  
Nucleotide Exchange ◽  
T Helper

Abstract Immature dendritic cells (DCs) specialize in antigen capture and maintain a highly dynamic pool of intracellular major histocompatibility complex class II (MHCII) that continuously recycles from peptide loading compartments to the plasma membrane and back again. This process facilitates sampling of environmental antigens for presentation to T helper cells. Here, we show that a signaling pathway mediated by the DC immunoreceptor tyrosine-based activation motif (ITAM)–containing adaptors (DAP12 and FcRγ) and Vav family guanine nucleotide exchange factors controls the half-life of surface peptide-MHCII (pMHCII) complexes and is critical for CD4 T-cell triggering in vitro. Strikingly, mice with disrupted DC ITAMs show defective T helper cell priming in vivo and are protected from experimental autoimmune encephalitis. Mechanistically, we show that deficiency in ITAM signaling results in increased pMHCII internalization, impaired recycling, and an accumulation of ubiquitinated MHCII species that are prematurely degraded in lysosomes. We propose a novel mechanism for control of T helper cell priming.

Dendritic cell-derived IL-2 production is regulated by IL-15 in humans and in mice

Blood ◽  
2005 ◽  
Vol 105 (2) ◽  
pp. 697-702 ◽  
Author(s):  
Sonia Feau ◽  
Valeria Facchinetti ◽  
Francesca Granucci ◽  
Stefania Citterio ◽  
David Jarrossay ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Molecular Mechanisms ◽  
Interleukin 2 ◽  
Adaptive Immune ◽  
Deficient Mice ◽  
Mouse System

Abstract Dendritic cells (DCs) are involved in the initiation and regulation of innate and adaptive immune responses. Several molecular mechanisms regulate these diverse DC functions, and we have previously reported that mouse dendritic cells (mDCs) can produce interleukin-2 (IL-2) in vitro and in vivo, in response to microbial activation and T-cell-mediated stimuli. This property is shared by different DC subtypes, including Langerhans cells. Here we show that, on appropriate stimulation, human DCs, both plasmacytoid and myeloid subtypes, also express IL-2. Interestingly, the production of IL-2 by myeloid DCs is induced by T-cell-mediated stimuli and depends on the presence of IL-15. The key role of this cytokine in regulating IL-2 production was also confirmed in the mouse system. In particular, we could show that DCs from IL-15-deficient mice were strongly impaired in the ability to produce IL-2 after interactions with different microbial stimuli. Our results indicate that DC-produced IL-2 is tightly coregulated with the expression of IL-15.

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