scholarly journals Fc gamma R(CD16) interaction with ligand induces Ca2+ mobilization and phosphoinositide turnover in human natural killer cells. Role of Ca2+ in Fc gamma R(CD16)-induced transcription and expression of lymphokine genes.

1989 ◽  
Vol 169 (2) ◽  
pp. 549-567 ◽  
Author(s):  
M A Cassatella ◽  
I Anegón ◽  
M C Cuturi ◽  
P Griskey ◽  
G Trinchieri ◽  
...  

In this study, we present evidence that interaction of Fc gamma R(CD16) with ligands (immune complexes or anti-CD16 antibodies) induces a rapid rise in [Ca2+]i and fast production of both inositol 1,4,5 triphosphate (IP3) and IP4 in homogeneous NK cell preparations. Part of the initial [Ca2+]i rise observed upon stimulation of NK cells with either anti-CD16 antibodies alone or after their crosslinking at the cell membrane depends on Ca2+ mobilization from intracellular stores, but sustained [Ca2+]i levels are maintained, after the initial spike, through influx of extracellular Ca2+. The [Ca2+]i rise is mediated, at least in part, by increases in IP3 after receptor-induced hydrolysis of membrane polyphosphoinositides (PPI). The role of extracellular Ca2+ in Fc gamma R(CD16)-dependent induction of lymphokine gene expression has been tested by evaluating production, mRNA accumulation and transcription of IFN-gamma and TNF in NK cells stimulated with Fc gamma R(CD16) ligands and/or rIL-2 in the presence of EGTA. Under these conditions, accumulation and transcription of both IFN-gamma and TNF mRNA induced by CD16 ligands, but not that induced by rIL-2, is completely abolished and neither cytokine can be detected at significant levels in the supernatant fluids of cells so treated. These data confirm that NK cell activation by specific ligands occurs through mechanisms distinct from those induced by IL-2, and indicate that extracellular Ca2+ represents a stringent requirement for cytokine production induced in NK cells through specific (Fc gamma R) stimulation. Our data also indicate that the [Ca2+]i rise induced upon Fc gamma R(CD16) crosslinking, though necessary, is not sufficient per se to induce activation of lymphokine genes, compatible with the hypothesis that Fc gamma R(CD16) crosslinking generates additional transducing signals that synergize with IL-2 to maximally activate NK cells.

1988 ◽  
Vol 167 (2) ◽  
pp. 452-472 ◽  
Author(s):  
I Anegón ◽  
M C Cuturi ◽  
G Trinchieri ◽  
B Perussia

We report evidence that FcR(CD16) on human NK cells are signal-transducing molecules that, upon ligand binding, induce transcription of genes encoding surface activation molecules [IL-2-R(CD25)] and cytokines (IFN-gamma and TNF) relevant to NK cell biology and functions. Homogeneous NK and T cell populations purified from short-term bulk cultures of PBMC with irradiated B lymphoblastoid cell lines were cultured in the presence of FcR ligands (particulate immune complexes or immobilized anti-CD16 antibodies) alone or with rIL-2. Upon 18 h of stimulation, NK cells express Tac, TfR, and 4F2 antigens and produce IFN-gamma and TNF; both effects are synergistically enhanced in the presence of rIL-2, which is itself ineffective. Treatment of NK cells with FcR(CD16) ligands induces accumulation of mRNA for IFN-gamma and TNF and, to a lesser extent, IL-2-R with fast kinetics also in the absence of de novo protein synthesis. rIL-2 and FcR(CD16) ligands synergize to induce mRNA accumulation. mRNA accumulation and transcription of TNF and IFN-gamma genes induced by FcR(CD16) ligands are greater than those induced by rIL-2, and the reverse is true for IL-2-R. The two stimuli do not synergize at the transcriptional level. These observations indicate that the mechanisms through which FcR(CD16) ligands and rIL-2 induce NK cell activation are, in part, distinct. Both operate at the transcriptional level, although other mechanisms are probably induced by the FcR ligand stimulus per se or in combination with other lymphokines and synergize at a post-transcriptional or translational level to enhance NK cell activation.


2021 ◽  
Vol 12 ◽  
Author(s):  
Elena Gianchecchi ◽  
Domenico V. Delfino ◽  
Alessandra Fierabracci

Autoimmune diseases recognize a multifactorial pathogenesis, although the exact mechanism responsible for their onset remains to be fully elucidated. Over the past few years, the role of natural killer (NK) cells in shaping immune responses has been highlighted even though their involvement is profoundly linked to the subpopulation involved and to the site where such interaction takes place. The aberrant number and functionality of NK cells have been reported in several different autoimmune disorders. In the present review, we report the most recent findings regarding the involvement of NK cells in both systemic and organ-specific autoimmune diseases, including type 1 diabetes (T1D), primary biliary cholangitis (PBC), systemic sclerosis, systemic lupus erythematosus (SLE), primary Sjögren syndrome, rheumatoid arthritis, and multiple sclerosis. In T1D, innate inflammation induces NK cell activation, disrupting the Treg function. In addition, certain genetic variants identified as risk factors for T1D influenced the activation of NK cells promoting their cytotoxic activity. The role of NK cells has also been demonstrated in the pathogenesis of PBC mediating direct or indirect biliary epithelial cell destruction. NK cell frequency and number were enhanced in both the peripheral blood and the liver of patients and associated with increased NK cell cytotoxic activity and perforin expression levels. NK cells were also involved in the perpetuation of disease through autoreactive CD4 T cell activation in the presence of antigen-presenting cells. In systemic sclerosis (SSc), in addition to phenotypic abnormalities, patients presented a reduction in CD56hi NK-cells. Moreover, NK cells presented a deficient killing activity. The influence of the activating and inhibitory killer cell immunoglobulin-like receptors (KIRs) has been investigated in SSc and SLE susceptibility. Furthermore, autoantibodies to KIRs have been identified in different systemic autoimmune conditions. Because of its role in modulating the immune-mediated pathology, NK subpopulation could represent a potential marker for disease activity and target for therapeutic intervention.


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.


1999 ◽  
Vol 190 (10) ◽  
pp. 1505-1516 ◽  
Author(s):  
Daniela Pende ◽  
Silvia Parolini ◽  
Anna Pessino ◽  
Simona Sivori ◽  
Raffaella Augugliaro ◽  
...  

Two major receptors involved in human natural cytotoxicity, NKp46 and NKp44, have recently been identified. However, experimental evidence suggested the existence of additional such receptor(s). In this study, by the generation of monoclonal antibodies (mAbs), we identified NKp30, a novel 30-kD triggering receptor selectively expressed by all resting and activated human natural killer (NK) cells. Although mAb-mediated cross-linking of NKp30 induces strong NK cell activation, mAb-mediated masking inhibits the NK cytotoxicity against normal or tumor target cells. NKp30 cooperates with NKp46 and/or NKp44 in the induction of NK-mediated cytotoxicity against the majority of target cells, whereas it represents the major triggering receptor in the killing of certain tumors. This novel receptor is associated with CD3ζ chains that become tyrosine phosphorylated upon sodium pervanadate treatment of NK cells. Molecular cloning of NKp30 cDNA revealed a member of the immunoglobulin superfamily, characterized by a single V-type domain and a charged residue in the transmembrane portion. Moreover, we show that NKp30 is encoded by the previously identified 1C7 gene, for which the function and the cellular distribution of the putative product were not identified in previous studies.


2008 ◽  
Vol 76 (11) ◽  
pp. 5100-5109 ◽  
Author(s):  
Mayra X. Hernandez Sanabria ◽  
Diego A. Vargas-Inchaustegui ◽  
Lijun Xin ◽  
Lynn Soong

ABSTRACT The importance of the interaction between natural killer (NK) cells and dendritic cells (DCs) in the expansion of antiviral and antitumor immune responses is well-documented; however, limited information on DC-NK cell interaction during parasitic infections is available. Given that some Leishmania parasites are known to prevent or suppress DC activation, we developed a DC-NK cell coculture system to examine the role of NK cells in modulating the functions of Leishmania-infected DCs. We found that the addition of freshly isolated, resting NK cells significantly promoted the activation of DCs that were preinfected with Leishmania amazonensis promastigotes and that these activated DCs, in turn, stimulated NK cell activation mostly via cell contact-dependent mechanisms. Notably, L. amazonensis amastigote infection failed to activate DCs, and this lack of DC activation could be partially reversed by the addition of preactivated NK (ANK) cells but not resting NK cells. Moreover, the adoptive transfer of ANK cells into L. amazonensis-infected mice markedly increased DC and T-cell activation and reduced tissue parasite loads at 1 and 3 weeks postinfection. These results suggest differential roles of DC-NK cell cross talk at different stages of Leishmania infection and provide new insight into the interplay of components of the innate immune system during parasitic infection.


2015 ◽  
Vol 212 (12) ◽  
pp. 2165-2182 ◽  
Author(s):  
Zhanguang Zhang ◽  
Ning Wu ◽  
Yan Lu ◽  
Dominique Davidson ◽  
Marco Colonna ◽  
...  

DNAM-1 (CD226) is an activating receptor expressed on natural killer (NK) cells, CD8+ T cells, and other immune cells. Upon recognition of its ligands, CD155 and CD112, DNAM-1 promotes NK cell–mediated elimination of transformed and virus-infected cells. It also has a key role in expansion and maintenance of virus-specific memory NK cells. Herein, the mechanism by which DNAM-1 controls NK cell–mediated cytotoxicity and cytokine production was elucidated. Cytotoxicity and cytokine production triggered by DNAM-1 were mediated via a conserved tyrosine- and asparagine-based motif in the cytoplasmic domain of DNAM-1. Upon phosphorylation by Src kinases, this motif enabled binding of DNAM-1 to adaptor Grb2, leading to activation of enzymes Vav-1, phosphatidylinositol 3′ kinase, and phospholipase C-γ1. It also promoted activation of kinases Erk and Akt, and calcium fluxes. Although, as reported, DNAM-1 promoted adhesion, this function was signal-independent and insufficient to promote cytotoxicity. DNAM-1 signaling was also required to enhance cytotoxicity, by increasing actin polymerization and granule polarization. We propose that DNAM-1 promotes NK cell activation via an immunoreceptor tyrosine tail (ITT)–like motif coupling DNAM-1 to Grb2 and other downstream effectors.


Immuno ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 305-331
Author(s):  
Sabrina Rizzo ◽  
Giovanna Schiuma ◽  
Silvia Beltrami ◽  
Valentina Gentili ◽  
Roberta Rizzo ◽  
...  

Natural Killer (NK) cells are key effectors of the innate immune system which represent the first line of defense against viral infections. NK cell activation depends on the engagement of a complex receptor repertoire expressed on their surface, consisting of both activating and inhibitory receptors. Among the known NK cell receptors, the family of killer Ig-like receptors (KIRs) consists in activating/inhibitory receptors that interact with specific human leukocyte antigen (HLA) molecules expressed on target cells. In particular, the expression of peculiar KIRs have been reported to be associated to viral infection susceptibility. Interestingly, a significant association between the development and onset of different human pathologies, such as tumors, neurodegeneration and infertility, and a clonal KIRs expression on NK cells has been described in presence of viral infections, supporting the crucial role of KIRs in defining the effect of viral infections in different tissues and organs. This review aims to report the state of art about the role of KIRs receptors in NK cell activation and viral infection control.


2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
FANG ZHOU ◽  
Darise Farris

Thrombotic thrombocytopenic purpura (TTP) is a rare life-threaten vascular autoimmune disease. There is no effective method to treat it in clinical trials since pathogenesis of TTP has not been fully elucidated. Here we investigate the role of NK cells in relapse development of TTP. Our results showed that the frequencies of CD3 − CD56 dim CD16 − and CD3 − CD56 bri CD16 − NK cells are increased in TTP patients with a history of relapse. Expression of CD107a, granzyme A and IFN-γ by CD3 − CD56 dim NK cells following in vitro stimulation with PMA/ionomycin / monensin is improved in the relapse group, compared with those on NK cells derived from TTP patients without relapse development. NK cells isolated from TTP patients with a history of relapse indicated stronger cytotoxicity to target K562 cells than those of NK cells derived from TTP patients without relapse development, suggesting prior activation of NK cells in vivo . Treatment with anti-human CD16 antibody up-regulates cytotoxicity of NK cells derived from TTP patients without relapse development. However, Anti-human CD16 antibody treatment does not affect cytotoxicity of NK cells isolated from TTP patients with a history of relapse, suggesting inability of CD16-mediated signaling in NK cells derived from TTP patients with relapse development. These data provide evidence of altered NK cell activation and/or licensing in TTP patients with a history of relapse modulated by CD16-mediated signaling and a new avenue of investigation into mechanisms of TTP immunopathogenesis.


2010 ◽  
Vol 40 (12) ◽  
pp. 3472-3477 ◽  
Author(s):  
Matthew B. B. McCall ◽  
Meta Roestenberg ◽  
Ivo Ploemen ◽  
Anne Teirlinck ◽  
Joost Hopman ◽  
...  

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 9521-9521
Author(s):  
H. N. Lode ◽  
Y. Zeng ◽  
S. Fest ◽  
G. Gaedicke

9521 Background: Fractalkine (FKN) is a unique CX3C chemokine (CX3CL1) known to induce adhesion and migration of leukocytes mediated by a membrane-bound and a soluble form. Methods: We found that FKN is expressed in >90% of 68 neuroblastoma (NB) samples as determined by cDNA microarray analysis. FKN expression was inversely correlated with MYCN amplification, suggesting a higher expression of FKN in MYCN non amplified tumors. We characterized the effect of FKN in the neuroblastoma microenvironment in a mouse model. We demonstrate that FKN released from NB cells mediate migration and adhesion of CD4+-, CD8+- and NK- cells and subsequent secretion of IFN-γ, in vitro and in vivo. However, the presence of FKN in NB microenvironments did not result in significant anti-NB activity. Results: Targeting of IL-2 into the NB microenvironment using anti-ganglioside GD2 antibody cytokine fusion proteins (ch14.18-IL-2) is currently under clinical evaluation. We investigated a the role of FKN in this context. For this purpose, IL-2 was targeted to GD2 positive NB microenvironments secreting FKN. Only mice bearing FKN and IL2 enriched NB microenvironments exhibited a reduction in primary tumor growth and a complete eradication of experimental liver metastases, in contrast to controls with only FKN or IL-2 enriched NB. This effect was specific since a non-specific antibody-IL-2 fusion protein ch225-IL-2 was ineffective. The mechanisms involved included NK-cell activation by targeted IL-2 into FKN rich NB as indicated by the enhancement of NK-cell mediated lysis using YAC-1 cells as targeted cells. The depletion of NK cells in vivo inhibited the therapeutic effect. Furthermore, co-culture of NXS2-FKN cells and NK cells in vitro induced the expression of IFN-γ by NK cells. However, the depletion of CD8+ T-cells in vivo abrogated the therapeutic effect, and these effector cells showed the highest cytolytic activity against NXS2 target cells in vitro. Finally, only the FKN and IL-2 enriched NB microenvironment resulted in T-cell activation and the release of proinflammatory cytokines. Conclusions: In conclusion our data suggest that targeted IL-2 therapy of FKN rich NB associated with MYCN non-amplified tumors may result in T-cell mediated immune responses. No significant financial relationships to disclose.


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