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 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.

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.

scholarly journals Natural Killer Cells: Potential Biomarkers and Therapeutic Target in Autoimmune Diseases?

2021 ◽  
Vol 12 ◽  
Author(s):  
Elena Gianchecchi ◽  
Domenico V. Delfino ◽  
Alessandra Fierabracci
Keyword(s):  
Systemic Sclerosis ◽  
Autoimmune Diseases ◽  
Cytotoxic Activity ◽  
Nk Cells ◽  
Natural Killer ◽  
T Cell Activation ◽  
Cell Activation ◽  
Nk Cell ◽  
Killer Cell

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.

scholarly journals NT5E/CD73 as Correlative Factor of Patient Survival and Natural Killer Cell Infiltration in Glioblastoma

2019 ◽  
Vol 8 (10) ◽  
pp. 1526 ◽  
Author(s):  
Jiao Wang ◽  
Sandro Matosevic
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Cell Activation ◽  
Patient Survival ◽  
Nk Cell ◽  
Killer Cell ◽  
Surface Protein ◽  
The Cancer Genome Atlas ◽  
Negative Prognostic Factor ◽  
A Cell

CD73, a cell-surface protein encoded by the gene NT5E, is overexpressed in glioblastoma (GBM), where it contributes to the tumor’s pathophysiology via the generation of immunosuppressive adenosine. Adenosinergic signaling, in turn, drives immunosuppression of natural killer (NK) cells through metabolic and functional reprogramming. The correlation of CD73 with patient survival in relation to GBM pathology and the intratumoral infiltration of NK cells has not been comprehensively studied before. Here, we present an analysis of the prognostic relevance of CD73 in GBM based on transcriptional gene expression from patient data from The Cancer Genome Atlas (TCGA) database. Utilizing bioinformatics data mining tools, we explore the relationship between GBM prognosis, NT5E expression, and intratumoral presence of NK cells. Our analysis demonstrates that CD73 is a negative prognostic factor for GBM and that presence of NK cells may associate with improved prognosis. Moreover, the interplay between expression of NT5E and specific NK genes hints to potential functional effects of CD73 on NK cell activation.

scholarly journals SARS-CoV-2 Spike 1 Protein Controls Natural Killer Cell Activation via the HLA-E/NKG2A Pathway

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1975 ◽  
Author(s):  
Daria Bortolotti ◽  
Valentina Gentili ◽  
Sabrina Rizzo ◽  
Antonella Rotola ◽  
Roberta Rizzo
Keyword(s):  
Epithelial Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Cell Activation ◽  
Nk Cell ◽  
Killer Cell ◽  
Lung Epithelial Cells ◽  
Lung Epithelial ◽  
Spike Proteins

Natural killer cells are important in the control of viral infections. However, the role of NK cells during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has previously not been identified. Peripheral blood NK cells from SARS-CoV and SARS-CoV-2 naïve subjects were evaluated for their activation, degranulation, and interferon-gamma expression in the presence of SARS-CoV and SARS-CoV-2 spike proteins. K562 and lung epithelial cells were transfected with spike proteins and co-cultured with NK cells. The analysis was performed by flow cytometry and immune fluorescence. SARS-CoV and SARS-CoV-2 spike proteins did not alter NK cell activation in a K562 in vitro model. On the contrary, SARS-CoV-2 spike 1 protein (SP1) intracellular expression by lung epithelial cells resulted in NK cell-reduced degranulation. Further experiments revealed a concomitant induction of HLA-E expression on the surface of lung epithelial cells and the recognition of an SP1-derived HLA-E-binding peptide. Simultaneously, there was increased modulation of the inhibitory receptor NKG2A/CD94 on NK cells when SP1 was expressed in lung epithelial cells. We ruled out the GATA3 transcription factor as being responsible for HLA-E increased levels and HLA-E/NKG2A interaction as implicated in NK cell exhaustion. We show for the first time that NK cells are affected by SP1 expression in lung epithelial cells via HLA-E/NKG2A interaction. The resulting NK cells’ exhaustion might contribute to immunopathogenesis in SARS-CoV-2 infection.

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 Natural Killer Cell Inhibitory Receptors Block Actin Cytoskeleton-dependent Recruitment of 2B4 (CD244) to Lipid Rafts

2002 ◽  
Vol 197 (1) ◽  
pp. 77-85 ◽  
Author(s):  
Carsten Watzl ◽  
Eric O. Long
Keyword(s):  
Actin Cytoskeleton ◽  
Natural Killer ◽  
Lipid Rafts ◽  
Cell Activation ◽  
Nk Cell ◽  
Killer Cell ◽  
General Mechanism ◽  
Target Cells ◽  
Inhibitory Receptors ◽  
Detergent Resistant Membrane

A dynamic balance of positive and negative signals regulates target cell lysis by natural killer (NK) cells upon engagement of a variety of different activation receptors and of inhibitory receptors that recruit the tyrosine phosphatase SHP-1. However, the step at which activation signals are blocked by SHP-1 is not known. We have been using activation receptor 2B4 (CD244) to study the influence of inhibitory receptors on NK cell activation. Engagement of inhibitory receptors by HLA class I on target cells blocks phosphorylation of 2B4, placing the inhibitory step at the level, or upstream of 2B4 phosphorylation. Here we show that phosphorylated 2B4, after engagement with either antibodies or target cells that express the 2B4 ligand, is found exclusively in a detergent-resistant membrane fraction that contains lipid rafts. Integrity of lipid rafts was essential for phosphorylation and activating function of 2B4. Coengagement of inhibitory receptors blocked 2B4 phosphorylation and 2B4 association with detergent-resistant membranes, indicating that inhibitory receptors function upstream of raft-dependent signals. Recruitment of 2B4 into detergent-resistant membrane fractions and 2B4 phosphorylation were dependent on actin polymerization. Blocking actin cytoskeleton-dependent raft recruitment of different receptors may be a general mechanism by which inhibitory receptors control NK cell activation.

scholarly journals A novel mechanism of natural killer cell response to anti-CTLA-4 therapy identified by integrative analysis of mouse and human tumors

2020 ◽  
Author(s):  
Emily F. Davis-Marcisak ◽  
Allison A. Fitzgerald ◽  
Michael D. Kessler ◽  
Ludmila Danilova ◽  
Elizabeth M. Jaffee ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Cell Activation ◽  
Nk Cell ◽  
Killer Cell ◽  
Mouse Tumors ◽  
Natural Killer Cell Response ◽  
Melanoma Patients ◽  
Inhibitory Antibodies ◽  
The Impact

AbstractImmune checkpoint-inhibitory antibodies (ICIs) are well-established immunotherapies. Despite this, the impact of ICI therapy on non-T cell intratumoral immune cells is ill-defined, restraining the improvement of ICI efficacy. Preclinical murine models of human disease are infrequently validated in clinical trials, impairing the identification of novel biological factors impacting clinical ICI response. To address this barrier, we used our previously described computational approach that integrates high-throughput single-cell RNA sequencing datasets to identify known and novel cellular alterations induced by ICIs that are conserved in mice and humans. We found a signature of intratumoral natural killer (NK) cell activation that is enriched in anti-CTLA-4 treated mouse tumors and correlates with longer overall survival and is predictive of anti-CTLA-4 (ipilimumab) response in melanoma patients. We demonstrate that human NK cells express CTLA-4, which directly binds anti-CTLA-4. These data reveal a novel role for NK cells in anti-CTLA-4 treatment and present opportunities to enhance ICI efficacy. Importantly, we provide a new computational tool for onco-immunology that can identify and validate biological observations across species.

scholarly journals Spatially Resolved In Silico Modeling of NKG2D Signaling Kinetics Reveals Key role of NKG2D and Vav1 Co-clustering in Generating Natural Killer cell Activation

2021 ◽  
Author(s):  
Rajdeep K Grewal ◽  
Jayajit Das
Keyword(s):  
Natural Killer ◽  
In Silico ◽  
Cell Activation ◽  
Nk Cell ◽  
Spatial Clustering ◽  
Killer Cell ◽  
Host Cells ◽  
Model Parameters ◽  
Imaging Data ◽  
Spatially Resolved

Natural Killer (NK) cells provide key resistance against viral infections and tumors. A diverse set of activating and inhibitory NK cell receptors (NKRs) interact with cognate ligands presented by target host cells, where integration of dueling signals initiated by the ligand-NKR interactions determines NK cell activation or tolerance. Imaging experiments over decades have shown micron and sub-micron scale spatial clustering of activating and inhibitory NKRs. The mechanistic roles of these clusters in affecting downstream signaling and activation are often unclear. To this end, we developed a predictive in silico framework by combining spatially resolved mechanistic agent based modeling, published TIRF imaging data, and parameter estimation to determine mechanisms by which formation and spatial movements of activating NKG2D microclusters affect early time NKG2D signaling kinetics in a human cell line NKL. We show co-clustering of NKG2D and the guanosine nucleotide exchange factor Vav1 in NKG2D microclusters plays a dominant role over ligand (ULBP3) rebinding in increasing production of phospho-Vav1(pVav1), an activation marker of early NKG2D signaling. The in silico model successfully predicts several scenarios of inhibition of NKG2D signaling and time course of NKG2D spatial clustering over a short (~3 min) interval. Modeling shows the presence of a spatial positive feedback relating formation and centripetal movements of NKG2D microclusters, and pVav1 production offers flexibility towards suppression of activating signals by inhibitory KIR ligands organized in inhomogeneous spatial patterns (e.g., a ring). Our in silico framework marks a major improvement in developing spatiotemporal signaling models with quantitatively estimated model parameters using imaging data.

Abstract P207: Mitochondrial Dysfunction And Natural Killer Cell Activation Stimulated By Il-17 Signaling From Th17 Cells In Response To Placental Ischemia During Pregnancy; Sarah Fitzgerald, Evangeline Deer, Owen Herrock, Tarek Ibrahim, Lorena Amaral, Denise Cornelius And Babbette Lamarca; 1 Department Of Pharmacology, University Of Mississippi Medical Center.

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Sarah Fitzgerald ◽  
Owen Herrock ◽  
Evangeline M Deer ◽  
Tarek Ibrahim ◽  
Babbette B Lamarca ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Th17 Cells ◽  
Cell Activation ◽  
Nk Cell ◽  
Medical Center ◽  
Killer Cell ◽  
Multisystem Disorder ◽  
Uterine Perfusion ◽  
Placental Ischemia

Preeclampsia (PE) is a multisystem disorder characterized by new onset hypertension associated with placental ischemia (PI), mitochondrial (mt) dysfunction, and an imbalance in T helper (TH) and Natural Killer (NK) cells during pregnancy. The reduced uterine perfusion pressure (RUPP) model is an established model for PE. We have previously shown an important role for IL-17 in hypertension and activation of NK cells in the RUPP rat. We don’t know the role for IL-17 or TH17 cells in contributing to NK cell mediated mt dysfunction and ROS associated with PI. Therefore, we hypothesize that hypertension in response to PI stimulated TH17 cells causes mt ROS mediated through IL-17 signaling to NK cells. On gestation day 12 (GD12) RUPP-induced TH17s (splenic CD4+/CD25- cells) were adoptively transferred (Ad-T) into normal pregnant (NP) rats. Recombinant mouse IL-17 receptor C (IL-17RC) (100 pg/day) was administered from GD14-19 via osmotic mini-pump. On GD19, samples were collected and mean arterial pressure (MAP) was measured. Mt respiration and mt ROS data was measured in isolated mt from renal and placental tissues using the Oxygraph 2K and fluorescent microplate reader, respectively. A one-way ANOVA with Bonferroni post hoc test was used for statistical analysis. MAP was increased in Ad-T rats (112 ± 0.72mmHg, n=14) compared to NP (92 ± 3.03mmHg, n=14) (p<0.05), and was lowered with IL-17RC (97.2± 2.14 mmHg, n=13). Circulating activated NK cells were significantly increased with Ad-T (3.326± 0.76 %gated, n=9) (p<0.0001) compared to NP (0.05± 0.05 %, n=11), and were attenuated with IL-17RC (0.42± 0.4 %, n=5) (p<0.01). Placental activated NK cells were significantly increased with Ad-T (2.5± 1.01 %, n=4) (p<0.05) compared to NP (0.03± 0.03 %, n=8) and were attenuated with IL-17RC (0.21± 0.12 %, n=4) (p<0.05). Renal mtROS increased in Ad-T (312.4 ± 44.7%, n=9) compared to NP (191.9 ± 20.5%, n=5). Placental mtROS significantly increased in Ad-T (312.5 ± 23.6%, n=9) (P<0.0005) compared to NP controls (134 ± 9.6%, n=5) (p<0.0001), and was decreased by administration of IL-17RC (174.5± 42.5 %, n=5) (p<0.0001). These data demonstrate that IL-17 signaling plays an important role in NK cell activation and tissue mt function in response to TH17 cells stimulated during PE.

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