scholarly journals Cytomegalovirus immunoevasin reveals the physiological role of “missing self” recognition in natural killer cell dependent virus control in vivo

2010 ◽  
Vol 207 (12) ◽  
pp. 2663-2673 ◽  
Author(s):  
Marina Babić ◽  
Michal Pyzik ◽  
Biljana Zafirova ◽  
Maja Mitrović ◽  
Višnja Butorac ◽  
...  
Keyword(s):  
Natural Killer ◽  
Cell Activation ◽  
Nk Cell ◽  
Killer Cell ◽  
Physiological Role ◽  
Dependent Manner ◽  
Class I Mhc ◽  
Mhc I ◽  
Missing Self

Cytomegaloviruses (CMVs) are renowned for interfering with the immune system of their hosts. To sidestep antigen presentation and destruction by CD8+ T cells, these viruses reduce expression of major histocompatibility complex class I (MHC I) molecules. However, this process sensitizes the virus-infected cells to natural killer (NK) cell–mediated killing via the “missing self” axis. Mouse cytomegalovirus (MCMV) uses m152 and m06 encoded proteins to inhibit surface expression of MHC I molecules. In addition, it encodes another protein, m04, which forms complexes with MHC I and escorts them to the cell surface. This mechanism is believed to prevent NK cell activation and killing by restoring the “self” signature and allowing the engagement of inhibitory Ly49 receptors on NK cells. Here we show that MCMV lacking m04 was attenuated in an NK cell– and MHC I–dependent manner. NK cell–mediated control of the infection was dependent on the presence of NK cell subsets expressing different inhibitory Ly49 receptors. In addition to providing evidence for immunoevasion strategies used by CMVs to avoid NK cell control via the missing-self pathway, our study is the first to demonstrate that missing self–dependent NK cell activation is biologically relevant in the protection against viral infection in vivo.

scholarly journals CD4+CD25+ regulatory T cells inhibit natural killer cell functions in a transforming growth factor–β–dependent manner

2005 ◽  
Vol 202 (8) ◽  
pp. 1075-1085 ◽  
Author(s):  
François Ghiringhelli ◽  
Cédric Ménard ◽  
Magali Terme ◽  
Caroline Flament ◽  
Julien Taieb ◽  
...  
Keyword(s):  
Growth Factor ◽  
Natural Killer ◽  
Cell Activation ◽  
Transforming Growth Factor ◽  
Nk Cell ◽  
Killer Cell ◽  
Receptor Expression ◽  
Dependent Manner ◽  
Cell Functions

Tumor growth promotes the expansion of CD4+CD25+ regulatory T (T reg) cells that counteract T cell–mediated immune responses. An inverse correlation between natural killer (NK) cell activation and T reg cell expansion in tumor-bearing patients, shown here, prompted us to address the role of T reg cells in controlling innate antitumor immunity. Our experiments indicate that human T reg cells expressed membrane-bound transforming growth factor (TGF)–β, which directly inhibited NK cell effector functions and down-regulated NKG2D receptors on the NK cell surface. Adoptive transfer of wild-type T reg cells but not TGF-β−/− T reg cells into nude mice suppressed NK cell–mediated cytotoxicity, reduced NKG2D receptor expression, and accelerated the growth of tumors that are normally controlled by NK cells. Conversely, the depletion of mouse T reg cells exacerbated NK cell proliferation and cytotoxicity in vivo. Human NK cell–mediated tumor recognition could also be restored by depletion of T reg cells from tumor-infiltrating lymphocytes. These findings support a role for T reg cells in blunting the NK cell arm of the innate immune system.

scholarly journals Coronaviruses induce the expression of the peptide antigen transporter TAP1.

2020 ◽  
Author(s):  
Shahan Mamoor
Keyword(s):  
Host Cell ◽  
Natural Killer ◽  
Nk Cell ◽  
Killer Cell ◽  
The United States ◽  
Class I ◽  
Class I Mhc ◽  
Mhc I

Coronavirus infection is an emerging public health threat in the United States and worldwide (1). We mined published microarray data to perform systems-level analysis of host cell transcription following infection with multiple coronavirus types in order to identify therapeutic targets and host cell vulnerabilities (2, 3). We identified the antigen peptide transported TAP1 as differentially expressed in vitro in a human cell line following infection with human coronavirus 229E and in vivo in the lungs of mice following infection with the severe acute respiratory distress syndrome SARS coronavirus. While TAP1 functions to enhance presentation of class I-associated peptides to CD8 cytotoxic T-cells, TAP1 also enhances presentation of major histocompatibility class I (MHC-I) receptors (4). One criteria natural killer cells use to lyse cells is the absence of surface MHC-I (5), and hepatitis C virus up-regulates TAP1 to increase surface expression of MHC-I and inhibit NK-cell cytotoxicity and promote infection (6). We propose coronaviruses similarly up-regulate TAP1 to impair natural killer cell-mediated cytotoxicity responses and avoid recognition by NK cells.

scholarly journals Soluble and Exosome-Bound α-Galactosylceramide Mediate Preferential Proliferation of Educated NK Cells with Increased Anti-Tumor Capacity

Cancers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 298
Author(s):  
Arnika K. Wagner ◽  
Ulf Gehrmann ◽  
Stefanie Hiltbrunner ◽  
Valentina Carannante ◽  
Thuy T. Luu ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cancer Immunotherapy ◽  
Nk Cell ◽  
Mouse Strains ◽  
Target Cells ◽  
Class I Mhc ◽  
Mhc I ◽  
Cell Responses ◽  
Missing Self

Natural killer (NK) cells can kill target cells via the recognition of stress molecules and down-regulation of major histocompatibility complex class I (MHC-I). Some NK cells are educated to recognize and kill cells that have lost their MHC-I expression, e.g., tumor or virus-infected cells. A desired property of cancer immunotherapy is, therefore, to activate educated NK cells during anti-tumor responses in vivo. We here analyze NK cell responses to α-galactosylceramide (αGC), a potent activator of invariant NKT (iNKT) cells, or to exosomes loaded with αGC. In mouse strains which express different MHC-I alleles using an extended NK cell flow cytometry panel, we show that αGC induces a biased NK cell proliferation of educated NK cells. Importantly, iNKT cell-induced activation of NK cells selectively increased in vivo missing self-responses, leading to more effective rejection of tumor cells. Exosomes from antigen-presenting cells are attractive anti-cancer therapy tools as they may induce both innate and adaptive immune responses, thereby addressing the hurdle of tumor heterogeneity. Adding αGC to antigen-loaded dendritic-cell-derived exosomes also led to an increase in missing self-responses in addition to boosted T and B cell responses. This study manifests αGC as an attractive adjuvant in cancer immunotherapy, as it increases the functional capacity of educated NK cells and enhances the innate, missing self-based antitumor response.

scholarly journals Monocytes control natural killer cell differentiation to effector phenotypes

Blood ◽  
2011 ◽  
Vol 117 (17) ◽  
pp. 4511-4518 ◽  
Author(s):  
Katrina Soderquest ◽  
Nick Powell ◽  
Carmelo Luci ◽  
Nico van Rooijen ◽  
Andrés Hidalgo ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Killer Cell ◽  
In Vivo Model ◽  
Dependent Manner ◽  
Nk Cell Differentiation

Abstract Natural killer (NK) cells play a major role in immunologic surveillance of cancer. Whether NK-cell subsets have specific roles during antitumor responses and what the signals are that drive their terminal maturation remain unclear. Using an in vivo model of tumor immunity, we show here that CD11bhiCD27low NK cells migrate to the tumor site to reject major histocompatibility complex class I negative tumors, a response that is severely impaired in Txb21−/− mice. The phenotypical analysis of Txb21-deficient mice shows that, in the absence of Txb21, NK-cell differentiation is arrested specifically at the CD11bhiCD27hi stage, resulting in the complete absence of terminally differentiated CD11bhiCD27low NK cells. Adoptive transfer experiments and radiation bone marrow chimera reveal that a Txb21+/+ environment rescues the CD11bhiCD27hi to CD11bhiCD27low transition of Txb21−/− NK cells. Furthermore, in vivo depletion of myeloid cells and in vitro coculture experiments demonstrate that spleen monocytes mediate the terminal differentiation of peripheral NK cells in a Txb21- and IL-15Rα–dependent manner. Together, these data reveal a novel, unrecognized role for Txb21 expression in monocytes in promoting NK-cell development and help appreciate how various NK-cell subsets are generated and participate in antitumor immunity.

scholarly journals Interferon-γ-Mediated Natural Killer Cell Activation by an AqueousPanax ginsengExtract

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Kazuyoshi Takeda ◽  
Ko Okumura
Keyword(s):  
Cytotoxic Activity ◽  
Nk Cells ◽  
Natural Killer ◽  
Aqueous Extract ◽  
Cell Activation ◽  
Mononuclear Cells ◽  
Nk Cell ◽  
Killer Cell ◽  
Cell Activity

Panax ginsengextracts are used in traditional herbal medicines, particularly in eastern Asia, but their effect on natural killer (NK) cell activity is not completely understood. This study aimed to examine the effects ofP. ginsengextracts on the cytotoxic activity of NK cells. We orally administeredP. ginsengextracts or ginsenosides to wild-type (WT) C57BL/6 (B6) and BALB/c mice and to B6 mice deficient in either recombination activating gene 2 (RAG-2) or interferon-γ(IFN-γ). We then tested the cytotoxic activity of NK cells (of spleen and liver mononuclear cells) against NK-sensitive YAC-1 cells. Oral administration ofP. ginsengaqueous extract augmented the cytotoxicity of NK cells in WT B6 and BALB/c mice and in RAG-2-deficient B6 mice, but not in IFN-γ-deficient B6 mice. This effect was only observed with the aqueous extract ofP. ginseng. Interestingly, the ginsenosides Rb1 and Rg1 did not augment NK cell cytotoxicity. These results demonstrated that the aqueousP. ginsengextract augmented NK cell activationin vivovia an IFN-γ-dependent pathway.

Molecular basis for positive and negative signaling by the natural killer cell receptor 2B4 (CD244)

Blood ◽  
2005 ◽  
Vol 105 (12) ◽  
pp. 4722-4729 ◽  
Author(s):  
Philipp Eissmann ◽  
Lisa Beauchamp ◽  
Joe Wooters ◽  
John C. Tilton ◽  
Eric O. Long ◽  
...  
Keyword(s):  
Natural Killer ◽  
Molecular Basis ◽  
Cell Activation ◽  
Nk Cell ◽  
Killer Cell ◽  
Cell Activity ◽  
Lymphocyte Activation ◽  
Cell Receptor ◽  
Dependent Manner ◽  
Lymphoproliferative Syndrome

Abstract Triggering of 2B4 (CD244) can induce natural killer (NK)-cell activation, costimulation, or even inhibition of NK-cell activity. Here, we investigate the molecular basis for the different signals generated by 2B4. We show that the first immunoreceptor tyrosine-based switch motif (ITSM) within the cytoplasmic tail of 2B4 is sufficient for 2B4-mediated NK-cell activation, whereas the third ITSM can negatively influence 2B4 signaling. We further identify signaling molecules that associate with 2B4. Signaling lymphocyte activation molecule-associated protein (SAP) can bind to all 4 ITSMs of 2B4 in a phosphorylation-dependent manner. The phosphorylated third ITSM can additionally recruit the phosphatases SHP-1, SHP-2, SHIP, and the inhibitory kinase Csk. SAP acts as an inhibitor of interactions between 2B4 and these negative regulatory molecules, explaining how 2B4 inhibits NK-cell activation in the absence of functional SAP, as occurs in cells from patients with X-linked lymphoproliferative syndrome (XLP). Recently, another function for SAP was proposed: SAP can recruit the kinase Fyn to the SLAM (CD150) immune receptor. We now show that Fyn can also associate with phosphorylated 2B4. Finally, we demonstrate that Fyn and Csk can both phosphorylate 2B4, suggesting a possible mechanism of 2B4 phosphorylation. (Blood. 2005;105:4722-4729)

scholarly journals How the Virus Outsmarts the Host: Function and Structure of Cytomegalovirus MHC-I-Like Molecules in the Evasion of Natural Killer Cell Surveillance

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Maria Jamela Revilleza ◽  
Rui Wang ◽  
Janet Mans ◽  
Manqing Hong ◽  
Kannan Natarajan ◽  
...  
Keyword(s):  
Natural Killer ◽  
Host Response ◽  
Cell Activation ◽  
Nk Cell ◽  
Killer Cell ◽  
Viral Fitness ◽  
Protein Fold ◽  
Viral Pathogens ◽  
Mhc I ◽  
Functional Features

Natural killer (NK) cells provide an initial host immune response to infection by many viral pathogens. Consequently, the viruses have evolved mechanisms to attenuate the host response, leading to improved viral fitness. One mechanism employed by members of theβ-herpesvirus family, which includes the cytomegaloviruses, is to modulate the expression of cell surface ligands recognized by NK cell activation molecules. A novel set of cytomegalovirus (CMV) genes, exemplified by the mouse m145 family, encode molecules that have structural and functional features similar to those of host major histocompatibility-encoded (MHC) class I molecules, some of which are known to contribute to immune evasion. In this review, we explore the function, structure, and evolution of MHC-I-like molecules of the CMVs and speculate on the dynamic development of novel immunoevasive functions based on the MHC-I protein fold.

scholarly journals Inducible down-regulation of MHC class I results in natural killer cell tolerance

2018 ◽  
Vol 216 (1) ◽  
pp. 99-116 ◽  
Author(s):  
Michael D. Bern ◽  
Bijal A. Parikh ◽  
Liping Yang ◽  
Diana L. Beckman ◽  
Jennifer Poursine-Laurent ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Mhc Class I ◽  
Nk Cell ◽  
Class I ◽  
Cell Tolerance ◽  
Down Regulation ◽  
Mhc I ◽  
Missing Self

Natural killer (NK) cells are innate lymphocytes that are thought to kill cells that down-regulate MHC class I (MHC-I) through “missing-self” recognition. NK cells from B2m−/− mice that lack surface MHC-I, however, are not autoreactive as predicted by the missing-self hypothesis. As a result, it is unclear if MHC-I down-regulation in vivo induces NK cell reactivity or tolerance to missing-self. Here, we generated a floxed B2m mouse to acutely down-regulate MHC-I in vivo in a host that normally expresses MHC-I. Global down-regulation of MHC-I induced NK cell hyporesponsiveness and tolerance to missing-self without overt missing-self reactivity. In contrast, down-regulation of MHC-I on a small fraction of hematopoietic cells triggered missing-self reactivity. Surprisingly, down-regulation of MHC-I only on CD4+ T cells predominately induced tolerance to missing-self without resetting NK cell responsiveness. In this setting, inflammation triggered substantial missing-self reactivity. These results show that MHC-I down-regulation can induce either NK cell tolerance or killing in vivo and that inflammation promotes missing-self reactivity.

scholarly journals Impaired natural killer cell self-education and “missing-self” responses in Ly49-deficient mice

Blood ◽  
2012 ◽  
Vol 120 (3) ◽  
pp. 592-602 ◽  
Author(s):  
Simon Bélanger ◽  
Megan M. Tu ◽  
Mir Munir Ahmed Rahim ◽  
Ahmad B. Mahmoud ◽  
Rajen Patel ◽  
...  
Keyword(s):  
Tumor Cell ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Killer Cell ◽  
Host Cells ◽  
Target Cells ◽  
Mhc I ◽  
Missing Self ◽  
Deficient Mice

Abstract Ly49-mediated recognition of MHC-I molecules on host cells is considered vital for natural killer (NK)–cell regulation and education; however, gene-deficient animal models are lacking because of the difficulty in deleting this large multigene family. Here, we describe NK gene complex knockdown (NKCKD) mice that lack expression of Ly49 and related MHC-I receptors on most NK cells. NKCKD NK cells exhibit defective killing of MHC-I–deficient, but otherwise normal, target cells, resulting in defective rejection by NKCKD mice of transplants from various types of MHC-I–deficient mice. Self–MHC-I immunosurveillance by NK cells in NKCKD mice can be rescued by self–MHC-I–specific Ly49 transgenes. Although NKCKD mice display defective recognition of MHC-I–deficient tumor cells, resulting in decreased in vivo tumor cell clearance, NKG2D- or antibody-dependent cell-mediated cytotoxicity–induced tumor cell cytotoxicity and cytokine production induced by activation receptors was efficient in Ly49-deficient NK cells, suggesting MHC-I education of NK cells is a single facet regulating their total potential. These results provide direct genetic evidence that Ly49 expression is necessary for NK-cell education to self–MHC-I molecules and that the absence of these receptors leads to loss of MHC-I–dependent “missing-self” immunosurveillance by NK cells.

Abstract 26: IL-17 Causes Hypertension, Reduced Fetal Weight And Natural Killer Cell Activation In The Absence Of T Cells

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Sarah J Fitzgerald ◽  
James Hogg ◽  
Evangeline Deer ◽  
Nathan Campbell ◽  
Owen Herrock ◽  
...  
Keyword(s):  
T Cells ◽  
Natural Killer ◽  
Rat Model ◽  
Cell Activation ◽  
Nk Cell ◽  
Killer Cell ◽  
Interleukin 17 ◽  
Sprague Dawley ◽  
Th Cells ◽  
Atp Production

Preeclampsia (PE) is characterized by new onset hypertension (HTN), intrauterine growth restriction (IUGR), multi-organ dysfunction, and is associated with increased inflammatory cytokines, such as interleukin 17 (IL-17). More recent studies demonstrate a role for mitochondrial (mt) dysfunction/mtROS in the pathogenesis of PE. Although we have shown T helper cells from a rat model of PE cause HTN and mt dysfunction the causative factors for mt dysfunction are still being identified. In addition, we have shown that IL-17 cause HTN, IUGR and activate natural killer (NK) cells, and cause mt dysfunction in pregnant Sprague Dawley rats. However, in our previous studies we couldn’t differentiate the effect of activated TH cells versus IL-17 to cause these characteristics of PE. The athymic nude rat model lacks mature T cells but does have other components of the immune system, and will thus allow us to examine the role of IL-17 in the absence of TH cells in the pathophysiology of PE. We hypothesize that in the absence of T cells IL-17 induces HTN, NK cell activation and IUGR which is associated with renal and placental mt dysfunction during pregnancy. To test our hypothesis, IL-17 (150 pg/day) was infused via osmotic minipumps inserted on gestation day (GD) 14. Blood pressure (MAP) and mt function were measured on GD19 and were compared to untreated pregnant (NP) athymic nude rats. In response to IL-17; MAP increased from 95±4mmHg in NP(n=6) to 115±2 in NP+IL-17(n=6) (p<0.001); pup weight decreased from 1.46±0.2 g in NP (n=6) to 0.98±0.07g in NP+IL-17 (n=6) (p<0.05); NK cell activation increased from 0±0 %lymphocytes in NP (n=3) to 0.4±0.1% lymphocytes in NP+IL-17 rats (n=6). Interestingly, placental mtROS reduced 54% fold compared to NP and renal mtROS reduced 51.2% compared to NP. ATP production increased from 15.53±1.6 pmol of O2/sec/mg in NP (n=3) to 105.5±91 pmol of O2/sec/mg in NP+IL-17 (n=3) in the placenta, and from 1196±460 pmol of O2/sec/mg in NP (n=4) to 2016±951 pmol of O2/sec/mg NP+IL17 (n=4) in the kidney. These results show that although IL-17 induces HTN, IUGR, and NK cell activation independent of T cells, T cells are necessary for reduced mitochondrial function observed in PE and in rat models of placental ischemia.

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