NK cell activation by dendritic cells (DCs) requires the formation of a synapse leading to IL-12 polarization in DCs

Blood ◽  
2004 ◽  
Vol 104 (10) ◽  
pp. 3267-3275 ◽  
Author(s):  
Christophe Borg ◽  
Abdelali Jalil ◽  
Diego Laderach ◽  
Kouji Maruyama ◽  
Hiro Wakasugi ◽  
...  

Abstract Mature dendritic cells (mDCs) can trigger the effector functions of natural killer (NK) cells. Knock-out, small-interfering RNA or neutralizing antibodies targeting interleukin 12 (IL-12) subunits revealed a critical role for IL-12 in NK cell interferon γ (IFN-γ) secretion promoted by mDCs. However, NK cell activation by DCs also required direct cell-to-cell contacts. DC-mediated NK cell activation involved the formation of stimulatory synapses between DCs and NK cells. The formation of DC/NK cell conjugates depended on cytoskeleton remodeling and lipid raft mobilization in DCs. Moreover, the disruption of the DC cytoskeleton using pharmacologic agents or the loss-of-function mutation of the Wiskott-Aldrich syndrome protein abolished the DC-mediated NK cell activation. Synapse formation promoted the polarized secretion of preassembled stores of IL-12 by DCs toward the NK cell. The synaptic delivery of IL-12 by DCs was required for IFN-γ secretion by NK cells, as assessed using inhibitors of cytoskeleton rearrangements and transwell experiments. Therefore, the cross-talk between DCs and NK cells is dictated by functional synapses. (Blood. 2004;104:3267-3275)

Blood ◽  
2005 ◽  
Vol 106 (7) ◽  
pp. 2252-2258 ◽  
Author(s):  
Thierry Walzer ◽  
Marc Dalod ◽  
Scott H. Robbins ◽  
Laurence Zitvogel ◽  
Eric Vivier

AbstractSeveral recent publications have focused on the newly described interactions between natural-killer (NK) cells and dendritic cells (DCs). Activated NK cells induce DC maturation either directly or in synergy with suboptimal levels of microbial signals. Immature DCs appear susceptible to autologous NK-cell-mediated cytolysis while mature DCs are protected. NK-cell-induced DC activation is dependent on both tumor necrosis factor-α (TNF-α)/interferon-γ (IFN-γ) secretion and a cell-cell contact involving NKp30. In vitro, interleukin-12 (IL-12)/IL-18, IL-15, and IFN-α/β production by activated DCs enhance, in turn, NK-cell IFN-γ production, proliferation, and cytotoxic potential, respectively. In vivo, NK-cell/DC interactions may occur in lymphoid organs as well as in nonlymphoid tissues, and their consequences are multiple. By inducing DC activation, NK-cell activation induced by tumor cells can indirectly promote antitumoral T-cell responses. Reciprocally, DCs activated through Toll-like receptors (TLRs) induce potent NK-cell activation in antiviral responses. Thus, DCs and NK cells are equipped with complementary sets of receptors that allow the recognition of various pathogenic agents, emphasizing the role of NK-cell/DC crosstalk in the coordination of innate and adaptive immune responses.


mBio ◽  
2017 ◽  
Vol 8 (4) ◽  
Author(s):  
Vivian Vasconcelos Costa ◽  
Weijian Ye ◽  
Qingfeng Chen ◽  
Mauro Martins Teixeira ◽  
Peter Preiser ◽  
...  

ABSTRACT Natural killer (NK) cells play a protective role against dengue virus (DENV) infection, but the cellular and molecular mechanisms are not fully understood. Using an optimized humanized mouse model, we show that human NK cells, through the secretion of gamma interferon (IFN-γ), are critical in the early defense against DENV infection. Depletion of NK cells or neutralization of IFN-γ leads to increased viremia and more severe thrombocytopenia and liver damage in humanized mice. In vitro studies using autologous human NK cells show that DENV-infected monocyte-derived dendritic cells (MDDCs), but not monocytes, activate NK cells in a contact-dependent manner, resulting in upregulation of CD69 and CD25 and secretion of IFN-γ. Blocking adhesion molecules (LFA-1, DNAM-1, CD2, and 2β4) on NK cells abolishes NK cell activation, IFN-γ secretion, and the control of DENV replication. NK cells activated by infected MDDCs also inhibit DENV infection in monocytes. These findings show the essential role of human NK cells in protection against acute DENV infection in vivo, identify adhesion molecules and dendritic cells required for NK cell activation, and delineate the sequence of events for NK cell activation and protection against DENV infection. IMPORTANCE Dengue is a mosquito-transmitted viral disease with a range of symptoms, from mild fever to life-threatening dengue hemorrhagic fever. The diverse disease manifestation is thought to result from a complex interplay between viral and host factors. Using mice engrafted with a human immune system, we show that human NK cells inhibit virus infection through secretion of the cytokine gamma interferon and reduce disease pathogenesis, including depletion of platelets and liver damage. During a natural infection, DENV initially infects dendritic cells in the skin. We find that NK cells interact with infected dendritic cells through physical contact mediated by adhesion molecules and become activated before they can control virus infection. These results show a critical role of human NK cells in controlling DENV infection in vivo and reveal the sequence of molecular and cellular events that activate NK cells to control dengue virus infection. IMPORTANCE Dengue is a mosquito-transmitted viral disease with a range of symptoms, from mild fever to life-threatening dengue hemorrhagic fever. The diverse disease manifestation is thought to result from a complex interplay between viral and host factors. Using mice engrafted with a human immune system, we show that human NK cells inhibit virus infection through secretion of the cytokine gamma interferon and reduce disease pathogenesis, including depletion of platelets and liver damage. During a natural infection, DENV initially infects dendritic cells in the skin. We find that NK cells interact with infected dendritic cells through physical contact mediated by adhesion molecules and become activated before they can control virus infection. These results show a critical role of human NK cells in controlling DENV infection in vivo and reveal the sequence of molecular and cellular events that activate NK cells to control dengue virus infection.


2002 ◽  
Vol 9 (3) ◽  
pp. 649-657 ◽  
Author(s):  
D. Haller ◽  
P. Serrant ◽  
D. Granato ◽  
E. J. Schiffrin ◽  
S. Blum

ABSTRACT NK cells are instrumental in innate immune responses, in particular for the early production of gamma interferon (IFN-γ) and other cytokines necessary to control certain bacterial, parasitic, and viral infections. NK cell-mediated effector functions are controlled by a fine balance between distinct receptors mediating activating and inhibitory signals; however, little is known about activating receptors on NK cells and their corresponding ligands. Several studies have shown that commensal lactobacilli isolated from the human gastrointestinal tract activate human mononuclear cells and are potent inducers of IFN-γ and monocyte-derived interleukin 12 (IL-12). NK cell activation was shown for Lactobacillus johnsonii La1. In this study the cellular mechanisms of in vitro NK cell activation by gram-positive bacteria were analyzed. Staphylococcus aureus- and L. johnsonii La1-mediated activation of CD3− CD16+ CD56+ human peripheral blood NK cells, including expression of the activation antigen CD69 and secretion of IFN-γ, required cell contact-dependent costimulation by autologous monocytes. S. aureus- and L. johnsonii-preactivated monocytes retained their capacity to induce NK cell activation. In contrast, cytokine-primed monocytes completely failed to induce NK cell activation unless bacteria were present. This suggests that phagocytosis of bacteria provided additional coactivation signals on accessory cells that may differ from those induced by tumor necrosis factor and IFN-γ. Blocking of costimulatory molecules by B7.1, B7.2, and IL-12 but not CD14 monoclonal antibodies inhibited S. aureus- and L. johnsonii-induced effector function of NK cells. Our data suggest an important role for accessory cell-derived signals in the process of NK cell activation by gram-positive bacteria.


2017 ◽  
Vol 9 (5) ◽  
pp. 511-525 ◽  
Author(s):  
Sophie M. Poznanski ◽  
Amanda J. Lee ◽  
Tina Nham ◽  
Evan Lusty ◽  
Margaret J. Larché ◽  
...  

The combination of interleukin (IL)-18 and IL-12 (IL-18+IL-12) potently stimulates natural killer (NK) cells, triggering an innate immune response to infections and cancers. Strategies exploiting the effects of IL-18+IL-12 have shown promise for cancer immunotherapy. However, studies have primarily characterized the NK cell response to IL-18+IL-12 in terms of interferon (IFN)-γ production, with little focus on other cytokines produced. IL-8 plays a critical role in activating and recruiting immune cells, but it also has tumor-promoting functions. IL-8 is classically produced by regulatory NK cells; however, cytotoxic NK cells do not typically produce IL-8. In this study, we uncover that stimulation with IL-18+IL-12 induces high levels of IL-8 production by ex vivo expanded and freshly isolated NK cells and NK cells in peripheral blood mononuclear cells. We further report that tumor necrosis factor (TNF)-α, produced by NK cells following IL-18+IL-12 stimulation, regulates IL-8 production. The IL-8 produced is in turn required for maximal IFN-γ and TNF-α production. These findings may have important implications for the immune response to infections and cancer immunotherapies. This study broadens our understanding of NK cell function and IL-18+IL-12 synergy by uncovering an unprecedented ability of IL-18+IL-12-activated peripheral blood NK cells to produce elevated levels of IL-8 and identifying the requirement for intermediates induced by IL-18+IL-12 for maximal cytokine production following stimulation.


2009 ◽  
Vol 16 (11) ◽  
pp. 1601-1606 ◽  
Author(s):  
Eva Maria Laabs ◽  
Wenhui Wu ◽  
Susana Mendez

ABSTRACT Cutaneous leishmaniasis due to Leishmania major is an emerging, chronic parasitic disease that causes disfigurement and social stigmatization. Drug therapy is inadequate, and there is no vaccine. Inoculation of virulent parasites (leishmanization) is the only intervention that has ever provided protection, because it mimics natural infection and immunity, but it was discontinued due to safety concerns (uncontrolled vaccinal lesions). In an effort to retain the benefits (immunity) while avoiding the side effects (lesions) of leishmanization, we immunized C57BL/6 mice with L. major and CpG DNA (Lm/CpG). This combination prevented lesions while inducing immunity. Also, the vaccination with live parasites and the Toll-like receptor 9 agonist enhanced innate immune responses by activating dermal dendritic cells (DCs) to produce cytokines. Here we report that the Lm/CpG vaccine induced dermal DCs, but not bone marrow-derived DCs, to produce interleukin-2 (IL-2). The release of this unusual DC-derived cytokine was concomitant with a peak in numbers of NK cells that produced gamma interferon (IFN-γ) and also enhanced activation of proliferation of IFN-γ+ CD4+ T cells. Parasite growth was controlled in Lm/CpG-vaccinated animals. This is the first demonstration of the ability of dermal DCs to produce IL-2 and of the activation of NK cells by vaccination in the context of leishmaniasis. Understanding how the Lm/CpG vaccine enhances innate immunity may provide new tools to develop vaccines against L. major, other chronic infectious diseases, or other conditions, such as cancer.


2020 ◽  
Vol 221 (12) ◽  
pp. 2060-2071 ◽  
Author(s):  
Alessandra Marolda ◽  
Kerstin Hünniger ◽  
Sarah Böttcher ◽  
Wolfgang Vivas ◽  
Jürgen Löffler ◽  
...  

Abstract Background Candida albicans and Candida glabrata are the 2 most prevalent Candida species causing bloodstream infections. Patterns of innate immune activation triggered by the 2 fungi differ considerably. Methods To analyze human natural killer (NK) cell activation by both species, we performed ex vivo whole-blood infection assays and confrontation assays with primary human NK cells. Results C. albicans was a stronger activator for isolated human NK cells than C. glabrata. In contrast, activation of blood NK cells, characterized by an upregulated surface exposure of early activation antigen CD69 and death receptor ligand TRAIL, as well as interferon-γ (IFN-γ) secretion, was more pronounced during C. glabrata infection. NK cell activation in blood is mediated by humoral mediators released by other immune cells and does not depend on direct activation by fungal cells. Cross-talk between Candida-confronted monocyte-derived dendritic cells (moDC) and NK cells resulted in the same NK activation phenotype as NK cells in human blood. Blocking experiments and cytokine substitution identified interleukin-12 as a critical mediator in regulation of primary NK cells by moDC. Conclusions Activation of human NK cells in response to Candida in human blood mainly occurs indirectly by mediators released from monocytic cells.


2004 ◽  
Vol 72 (9) ◽  
pp. 5089-5096 ◽  
Author(s):  
T. Kikuchi ◽  
C. L. Hahn ◽  
S. Tanaka ◽  
S. E. Barbour ◽  
H. A. Schenkein ◽  
...  

ABSTRACT Human immunoglobulin G2 (IgG2) responses are gamma interferon (IFN-γ) dependent, and monocyte-derived dendritic cells (mDCs) promote IgG2 production. DCs spontaneously emerge from monocytes in cultures prepared from localized aggressive periodontitis (LagP) patients, and these patients have high levels of IgG2 that is reactive with Actinobacillus actinomycetemcomitans. These results prompted the hypothesis that an interaction between mDCs and A. actinomycetemcomitans promotes IFN-γ production, and IFN-γ is known to promote both immunopathology and protective IgG2. A. actinomycetemcomitans induced mDCs to produce interleukin-12 (IL-12), and the addition of A. actinomycetemcomitans and DCs to cultured peripheral blood lymphocytes elicited high levels of IFN-γ within just 24 h. In contrast, IL-4 was not detectable although DC-derived IL-10 production was apparent. A. actinomycetemcomitans-stimulated macrophages prepared from the same monocytes lacked the ability to induce IL-12 or IFN-γ responses. NK cells of the innate immune system were the primary source of this early IFN-γ, although CD8 T cells also contributed some. The NK cell-derived IFN-γ was IL-12 dependent, and A. actinomycetemcomitans-DC interactions were Toll-like receptor 4 dependent. A. actinomycetemcomitans and A. actinomycetemcomitans lipopolysaccharide (LPS) were more potent than Escherichia coli and E. coli LPS in the ability to induce DC IL-12 and IFN-γ. The ability of A. actinomycetemcomitans-stimulated DCs to induce NK cells to rapidly produce IFN-γ in the absence of detectable IL-4 suggests their potential for skewing responses toward Th1. This may help explain the presence of Th1-associated cytokines in gingival crevicular fluid (GCF) from LagP patients and the high levels of IgG2 in their serum and GCF that is reactive with A. actinomycetemcomitans.


2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Sabine Kossmann ◽  
Melanie Schwenk ◽  
Michael Hausding ◽  
Hanhan Hu ◽  
Maria I Schmidgen ◽  
...  

Rationale Immune cells contribute to angiotensin II (ATII) induced vascular dysfunction and inflammation. However, the mechanisms of recruitment and immune effector pathways remain incompletely understood. Objective We tested the hypothesis that interferon-gamma (IFN-γ) and natural killer (NK) cells play a pivotal role in ATII-driven vascular inflammation. Methods and results IFN-γ -/- and Tbx21 -/- mice were partially protected from ATII-induced vascular endothelial and smooth muscle dysfunction, whereas mice overexpressing IFN-γ showed constitutive vascular dysfunction. Absence of T-bet, the IFN-γ transcription factor encoded by Tbx21, reduced vascular superoxide and peroxynitrite formation and attenuated expression of NADPH oxidase subunits as well as inducible NO synthase, monocyte chemoattractant protein 1 and interleukin 12 in aortas of ATII-infused mice. Compared to controls, IFN-γ -/- and Tbx21 -/- mice were characterized by reduced ATII-mediated vascular recruitment of both NK1.1 + NK-cells as the major producers of IFN-γ and CD11b + Gr-1 low IL-12 secreting monocytes. Selective depletion and adoptive transfer experiments identified NK-cells as essential contributors to vascular dysfunction and showed that T-bet + LysM + myelomonocytic cells were required for NK-cell recruitment into vascular tissue and local IFN-γ production. Conclusion We provide first evidence that NK-cells play an essential role in ATII-induced vascular dysfunction. In addition, we disclose the T-bet-IFN-γ pathway and mutual monocyte-NK-cell activation as potential therapeutic targets in cardiovascular disease.


2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Song Chen ◽  
Ran Ding ◽  
Yan Zhou ◽  
Xian Zhang ◽  
Rui Zhu ◽  
...  

YCP, as a kind of natural polysaccharides from the mycelium of marine filamentous fungusPhoma herbarumYS4108, has great antitumor potentialviaenhancement of host immune response, but little is known about the molecular mechanisms. In the present study, we mainly focused on the effects and mechanisms of YCP on the specific immunity mediated by dendritic cells (DCs) and T cells. T cell /DC activation-related factors including interferon- (IFN-)γ, interleukin-12 (IL-12), and IL-4 were examined with ELISA. Receptor knock-out mice and fluorescence-activated cell sorting are used to analyze the YCP-binding receptor of T cells and DCs. RT-PCR is utilized to measure MAGE-A3 for analyzing the tumor-specific killing effect. In our study, we demonstrated YCP can provide the second signal for T cell activation, proliferation, and IFN-γproduction through binding to toll-like receptor- (TLR-) 2 and TLR-4. YCP could effectively promote IL-12 secretion and expression of markers (CD80, CD86, and MHC II)viaTLR-4 on DCs. Antigen-specific immunity against mouse melanoma cells was strengthened through the activation of T cells and the enhancement of capacity of DCs by YCP. The data supported that YCP can exhibit specific immunomodulatory capacity mediated by T cells and DCs.


2020 ◽  
Vol 55 (5) ◽  
pp. 1802422
Author(s):  
Justine Devulder ◽  
Cécile Chenivesse ◽  
Valérie Ledroit ◽  
Stéphanie Fry ◽  
Pierre-Emmanuel Lobert ◽  
...  

Rhinovirus infections are the main cause of asthma exacerbations. As natural killer (NK) cells are important actors of the antiviral innate response, we aimed at evaluating the functions of NK cells from severe asthma patients in response to rhinovirus-like molecules or rhinoviruses.Peripheral blood mononuclear cells from patients with severe asthma and healthy donors were stimulated with pathogen-like molecules or with the rhinoviruses (RV)-A9 and RV-2. NK cell activation, degranulation and interferon (IFN)-γ expression were analysed.NK cells from severe asthma patients were less cytotoxic than those from healthy donors in response to toll-like receptor (TLR)3, TLR7/8 or RV-A9 but not in response to RV-2 stimulation. Furthermore, when cultured with interleukin (IL)-12+IL-15, cytokines which are produced during viral infections, NK cells from patients with severe asthma were less cytotoxic and expressed less IFN-γ than NK cells from healthy donors. NK cells from severe asthmatics exhibited an exhausted phenotype, with an increased expression of the checkpoint molecule Tim-3.Together, our findings indicate that the activation of NK cells from patients with severe asthma may be insufficient during some but not all respiratory infections. The exhausted phenotype may participate in NK cell impairment and aggravation of viral-induced asthma exacerbation in these patients.


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