Umbilical Mesenchymal Stem Cell-Derived Extracellular Vesicle Conditioning Has an Immunosuppressive Effect on NK Cells

2021 ◽  
Author(s):  
G. Dostert ◽  
V. Jouan-Hureaux ◽  
H. Louis ◽  
É. Velot
Keyword(s):  
Flow Cytometry ◽  
Stem Cell ◽  
Mesenchymal Stem Cell ◽  
Nk Cells ◽  
Cell Activation ◽  
Nk Cell ◽  
Cell Communication ◽  
K562 Cells ◽  
Cell Cytotoxicity ◽  
Nk Cell Cytotoxicity

Background: In peripheral blood, human natural killer (NK) cells are immunological cells that nearly don’t express the ectonucleotidase CD73 on their plasma membrane. When exposed to mesenchymal stem cells (MSCs), NK cells are able to acquire CD73. MSCs are known to be CD73-positive (CD73+) and also to modulate the immune system, e.g. through adenosynergic pathway by ectonucleosidases, such as CD73. Extracellular vesicles (EVs) are involved in cell-to-cell communication. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have emerged as paracrine mediators that are part of MSC immunomodulatory effects including immunosuppressive properties and immune privilege. Objective: The aim of our work was to study if CD73 could be acquired by NK cells through cell-to-cell communication with MSC-EVs as cell culture additives. We also hypothesised that MSC-EVs would act as tolerance inducers to attenuate NK cell cytotoxicity. Methods: Cell isolation was made from human umbilical cords for MSCs and from human peripheral blood for NK cells. MSC-EVs were isolated by ultracentrifugation and filtration, then characterized by nanoparticle tracking assay and flow cytometry (CD9, 63, 81 and 73). MSC-EV interaction with NK cells was monitored by PKH67 staining. NK cell activation was followed by measuring the expression of CD73 and NK-activating receptor natural-killer group 2, member D (NKG2D) by flow cytometry. The cytotoxicity of NK cells or EV-conditioned NK cells was evaluated after co-culture with K562 cells. Results: We showed that MSC-EVs are nanoparticles able to express CD73 and interact with NK cells. MSC-EV conditioned NK cells seem to increase CD73 and decrease NKG2D through an EV-mediated mechanism. MSC-EVs have an immunosuppressive effect on NK cells by preventing NK cell activation and NK cell cytotoxicity towards K562 cells. Conclusions: Our results demonstrate that MSC-EVs could influence NK cell behaviour and act as immunosuppressant cell-based products.

Development and Function of NK and T Cells in AML Patients after Allogeneic Stem Cell Transplantation (SCT).

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3244-3244
Author(s):  
Gabriele Multhoff ◽  
Catharina Gross ◽  
Anne Dickinson ◽  
Ernst Holler
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
T Cells ◽  
Stem Cell ◽  
Nk Cells ◽  
Nk Cell ◽  
Granzyme B ◽  
Hla Class I ◽  
K562 Cells ◽  
Cytolytic Response

Abstract Purpose: Hsp70 was frequently found on the plasma membrane of bone marrow-derived leukemic blasts, but not on normal bone marrow cells. Hsp70 membrane expression could be correlated with protection against therapy-induced apoptosis (Nylandsted et al 2004). In contrast, these tumor cells have been found to be highly sensitive to the cytolytic attack mediated by NK cells. In vitro, Hsp70-activated NK cells efficiently lysed autologous Hsp70 membrane-positive leukemic blasts (Gehrmann et al 2003). Granzyme B release served as a surrogate marker for estimating the cytolytic response of NK cells against Hsp70 membrane-positive tumor target cells (Gross et al 2003). Here, we studied the development of NK and T cells in AML patients (n=6) after allogeneic SCT at different time points (days 14–20, 45, 90, 180, 1 year) after allogeneic stem cell transplantation (SCT). Methods: HLA class I, HLA-E and Hsp70 surface expression was determined on all patient-derived leukemic blasts of the bone marrow by flow cytometry. The amount of NK and T cells was investigated by multicolor flow cytometry using CD3/ CD16 and CD56 and CD94/ CD56 antibody-combinations detecting NK cell specific markers. Effector cell function was tested in a granzyme B ELISPOT assay against patient-derived leukemic blasts and K562 cells. Results: All tested leukemic blasts were positive for HLA class I, HLA-E, and Hsp70. After induction therapy the amount of CD3-negative, CD56/CD94-positive NK cells was 28±16%, that of CD3-positive T cells was 58±3%. On days 14–21 after allogeneic SCT, 58±9% of the donor-derived peripheral blood lymphocytes (PBL) were CD3-negative, CD56/CD94-positive NK cells; the amount of CD3-positive T cells was 26±7.5%. On day 45, the amount of NK cells further increased up to 68±7.9%; that of T cells further decreased down to 16±5.6%. On day 90 and day 180 the amount of NK cells was still 41±10%; that of T cells was 29±12%. Interestingly, high NK cell counts correlated with an increased cytolytic response against leukemic blast and K562 cells. One year after allogeneic SCT, NK (20±1%) and T cell (52±18%) ratios were comparable to that of healthy human individuals. Conclusions: Between days 14 and 180 after allogeneic SCT, the amount of NK cells was significantly elevated if compared to that of T cells. Concomitantly, cytolytic function against leukemic blasts was significantly elevated. Normal levels, in the composition of NK and T cells were reached 1 year after SCT. Project funded by EU-TRANS-EUROPE grant QLK3-CT-2002-01936.

AFM13 Is the Most Advanced Bispecific NK-Cell Engaging Antibody in Clinical Development Substantially Enhancing NK-Cell Effector Function and Proliferation

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1764-1764 ◽  
Author(s):  
Jens Pahl ◽  
Uwe Reusch ◽  
Thorsten Gantke ◽  
Anne Kerber ◽  
Joachim Koch ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Activation ◽  
Nk Cell ◽  
Target Cells ◽  
Cell Cytotoxicity ◽  
Cell Receptors ◽  
Cell Responses ◽  
Nk Cell Receptors ◽  
Ifn Γ ◽  
Nk Cell Cytotoxicity

Abstract Introduction: AFM13 is an NK-cell engaging CD30/CD16A bispecific tetravalent TandAb antibody currently in phase 2 clinical development in Hodgkin lymphoma (HL) and other CD30+ malignancies. It engages NK-cells through CD16A with high affinity and specificity and confers significantly stronger NK-cell activation compared to other therapeutic antibodies. We have previously shown synergistic efficacy when NK-cell activation by AFM13 is combined with check-point modulation such as anti-PD-1 treatment, which is known to unleash T cell and NK-cell activity. The goal of this study was to identify further candidates for combination treatments and biomarkers that potentially indicate NK-cell responses to AFM13 treatment. Methods: AFM13-mediated NK-cell cytotoxicity and IFN-γ production after 4-hour interaction with HL cell lines was measured by 51Cr release assays and flow cytometry, respectively. Expression of NK-cell receptors, NK-cell proliferation (CFSE dilution) and expansion (absolute cell counts) was analyzed by flow cytometry. Results: The interaction of NK-cells with AFM13-coated tumor cells up-regulated the expression of NK-cell receptors such as CD25, CD69, CD137/4-1BB as well as molecules that may serve as NK-cell check-points when compared with the unrelated NK-cell binding TandAb AFM12 that does not bind to target cells. Importantly, CD16A engagement by AFM13 enhanced the proliferation and expansion potential of NK-cells when subsequently incubated with IL-15 or with particularly low doses of IL-2. NK-cell cytotoxicity and IFN-γ production was substantially increased towards CD30+ tumor cells in the presence of AFM13. Even target cells resistant to naïve and IL-2/IL-15-activated NK-cells were susceptible to AFM13-induced NK-cell cytotoxicity. AFM13 concentrations of as low as 10-2 µg/mL resulted in maximal activity while AFM13 was significantly more potent than native anti-CD30 IgG1 antibody. NK-cell activation by IL-2 or IL-15 had a synergistic effect on AFM13-mediated cytotoxicity. Conclusion: AFM13 specifically enhances the cytotoxic, proliferative and cytokine-producing potential of NK-cells. Our data indicate that the distinctive modulation of NK-cell receptors can be utilized to monitor NK-cell responses during AFM13 therapy and provides candidates for therapeutic combination strategies. Moreover, the combination with low doses of IL-2 or with IL-15 may expand the quantity of tumor-reactive NK-cells after AFM13 treatment and promote NK-cell functionality in the tumor microenvironment in cancer patients. Disclosures Reusch: Affimed: Employment, Patents & Royalties: Patents. Gantke:Affimed GmbH: Employment. Kerber:Affimed: Employment. Koch:Affimed: Employment. Treder:Affimed: Employment. Cerwenka:Affimed: Research Funding.

siRNA Inactivation of the Inhibitory Receptor NKG2A Augments the Anti-Tumor Effects of Adoptively Transferred NK Cells In Tumor-Bearing Hosts

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1015-1015 ◽  
Author(s):  
Elissa Furutani ◽  
Su Su ◽  
Aleah Smith ◽  
Maria Berg ◽  
Richard Childs
Keyword(s):  
Flow Cytometry ◽  
Nk Cells ◽  
Nk Cell ◽  
Tumor Burden ◽  
Cell Cytotoxicity ◽  
Inhibitory Receptor ◽  
Inhibitory Receptors ◽  
Tumor Bearing ◽  
Nk Cell Cytotoxicity

Abstract Abstract 1015 Natural killer (NK) cells are a component of the innate immune system that target both tumors and virally infected cells. NK cell killing of tumors is regulated by a delicate balance of activating and inhibitory receptors. These inhibitory receptors bind HLA ligands which prevent NK cell targeting of normal “self” cells. Up regulation of surface expression of HLA molecules has been utilized by tumors as a method to evade NK cell cytotoxicity. Disrupting the function or expression of inhibitory receptors on NK cells could potentially be used as a method to overcome this effect. While most inhibitory receptors are present in only a subset of NK cells, NK cells universally express the HLA-E binding inhibitory receptor NKG2A. We hypothesized that siRNA inactivation of NK cell NKG2A would could be used as a therapeutic approach to enhance NK cell tumor cytotoxicity in vivo. The human natural killer cell line NKL was transduced with lentiviral vectors encoding shRNA targeting various regions of the NKG2A transcript. Following lentiviral transduction, knockdown of receptor expression was confirmed by flow cytometry and RT-qPCR. Compared to wild type (WT) and GFP-transduced NKL controls, NKG2A silenced NKL cells had increased secretion of IFN-gamma and Fas-L by ELISA and increased granzymes A and B and Nkp30 expression by flow cytometry. In contrast, expression of NKG2D, Nkp44, Nkp46, LFA-1, DNAM, and TRAIL was not altered by NKG2A silencing. Chromium-based cytotoxicity assays showed shRNA knockdown of NKG2A significantly enhanced NK cell cytotoxicity of tumor cells: at a 20:1 effector to target ratio, NKG2A knockdown NKLs, WT NKLs and GFP-transduced NKLs induced 68.9%, 8.2% and 8.3% lysis respectively of 721.221 EBV-LCL tumor targets (p=0.001). Remarkably, NKG2A silencing enhanced NKL killing of both HLA-E positive (721.221 EBV-LCL and 526 melanoma cells) and HLA-E negative (K562) tumor cell lines, suggesting NKG2A inactivation increased NK cell cytotoxicity through both HLA-E dependent and independent mechanisms. Using a xenogeneic model, we next explored the in vivo effects of transferring NKG2A silenced NK cells in tumor bearing mice. Immunodeficient NSG mice were injected with 1 million human luciferase transduced 721.221 HLA-E expressing EBV-LCL tumor cells. Twenty-four hours later, tumor-bearing mice were injected with 2–5 million WT NKL cells, GFP-control-transduced NKL, or NKG2A silenced NKL cells, then received IL-2 sq for 10 days to induce in vivo NK cell proliferation. NKL numbers in blood were subsequently analyzed by flow cytometry and tumor burden was assessed by luciferase-based bioluminescence imaging (BLI). At 16 and 21 days following adoptive NK cell transfer, BLI showed that recipients of NKG2A silenced NKL cells had slower tumor growth and significantly smaller tumor burden compared to NKL wt and NKL-GFP transduced controls (figure). Importantly, no toxicity related to infusing NKG2A inactivated NK cells was observed. These in vitro and in vivo data suggest shRNA knockdown of the NKG2A inhibitory receptor could be used as a method to augment NK cell tumor cytotoxicity in patients with hematological malignancies. Figure: Tumor burden in mice Luciferase-tagged 721.221 HLA-E EBV LCLs were injected into mice and imaged using a bioluminescence imager at days 10, 16, and 22 following NKL injection. 5 mice were followed in each group. Figure:. Tumor burden in mice . / Luciferase-tagged 721.221 HLA-E EBV LCLs were injected into mice and imaged using a bioluminescence imager at days 10, 16, and 22 following NKL injection. 5 mice were followed in each group. Disclosures: No relevant conflicts of interest to declare.

scholarly journals NK cells converge lytic granules to promote cytotoxicity and prevent bystander killing

2016 ◽  
Vol 215 (6) ◽  
pp. 875-889 ◽  
Author(s):  
Hsiang-Ting Hsu ◽  
Emily M. Mace ◽  
Alexandre F. Carisey ◽  
Dixita I. Viswanath ◽  
Athanasia E. Christakou ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Activation ◽  
Nk Cell ◽  
Cell Cytotoxicity ◽  
Microtubule Organizing Center ◽  
Lytic Granules ◽  
Nk Cell Cytotoxicity ◽  
Bystander Killing ◽  
Lysosome Related Organelles ◽  
The Impact

Natural killer (NK) cell activation triggers sequential cellular events leading to destruction of diseased cells. We previously identified lytic granule convergence, a dynein- and integrin signal–dependent movement of lysosome-related organelles to the microtubule-organizing center, as an early step in the cell biological process underlying NK cell cytotoxicity. Why lytic granules converge during NK cell cytotoxicity, however, remains unclear. We experimentally controlled the availability of human ligands to regulate NK cell signaling and promote granule convergence with either directed or nondirected degranulation. By the use of acoustic trap microscopy, we generated specific effector–target cell arrangements to define the impact of the two modes of degranulation. NK cells with converged granules had greater targeted and less nonspecific “bystander” killing. Additionally, NK cells in which dynein was inhibited or integrin blocked under physiological conditions demonstrated increased nondirected degranulation and bystander killing. Thus, NK cells converge lytic granules and thereby improve the efficiency of targeted killing and prevent collateral damage to neighboring healthy cells.

In-Vitro Culture of Human CD80/IL2 Lentivirus Transduced Acute Myeloid Leukemia Cells (AML) Promote NK Cell Activation and Cytolytic Activity

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2969-2969
Author(s):  
Wendy Ingram ◽  
Lucas Chan ◽  
Hayrettin Guven ◽  
Shahram Kordasti ◽  
Linda Barber ◽  
...  
Keyword(s):  
Cell Culture ◽  
T Cells ◽  
Nk Cells ◽  
Cell Activation ◽  
Nk Cell ◽  
Cell Activity ◽  
Cell Cytotoxicity ◽  
Release Assay ◽  
Nk Cell Cytotoxicity

Abstract Natural killer (NK) cells are increasingly recognized as an important component in the graft versus leukemia response following allogeneic hematopoietic stem cell transplantation. Immunotherapeutic strategies aim to promote NK cell activity however, the presence of regulatory T cells (Tregs) which inhibit effector immune responses pose a potential challenge to the efficacy of such regimens. We have previously shown that ‘in-vitro’ culture of AML cells transduced with a self-inactivating lentivirus (LV) encoding CD80 (B7.1) and IL2 enhance allogeneic (allo) and autologous (auto) T cell proliferation and cytotoxicity. The effect on NK cell activity and Tregs has not previously been studied and is of particular importance as IL2 stimulates NK cell and Treg activity. Peripheral blood mononuclear cells (PBMCs) from healthy donors (allo) or AML patients (auto) were cultured for 7 days ‘in-vitro’ with either unmodified or LV-CD80/IL2 AMLs. The number of NK cells (CD3−CD56+) and Tregs (CD3+CD4+CD25highFoxp3+) was examined by multi-color flow cytometry. We observe an increase in the number of NK cells (p<0.001) with an increase in the expression of the activation receptors NKp30, NKp44, CD244, CD25, CD69 and HLA-DR following allo culture with LV-CD80/IL2 AML compared with unmodified AML. Autologous culture provides a weaker stimulus ‘in-vitro’ however, a higher number of NK cells (p=0.002) and a consistent increased expression of the activation receptors NKp30, NKp44, NKp46, NKG2D, NKG2C and CD69, as well as up regulation of the cytolytic marker CD107a was detected following auto stimulation with LV-CD80/IL2 AML compared with unmodified AML. Up regulation of CD107a was also observed in allo cultures stimulated with both unmodified and LV-CD80/IL2 AML cells. In contrast, a consistent increase in the number of Tregs was observed following allo (p=0.043) but not auto (p=0.515) LV-CD80/IL2 AML culture. Foxp3 may be unregulated on activated CD4+ T cells therefore the number of CD3+CD4+CD25highFoxp3+CD27+ Tregs was also examined. An increase in the number of CD27+ Tregs was observed following allo (p=0.017) but not auto (p=0.807) LV-CD80/IL2 AML cell culture. A standard 51Cr release assay was used to examine cytotoxicity against primary unmodified AMLs on days 0 and 7 following LV-CD80/IL2 AML cell culture. Tregs are capable of suppressing CD4+ and CD8+ T cell and NK cell cytotoxicity, therefore lysis of unmodified AMLs was initially examined using whole PBMCs as effectors. Even in the presence of Tregs an increase in lysis of allo unmodified AMLs was observed: 2.2% day 0, 4.6% following culture with unmodified AMLs; 20.4% following LV-CD80/IL2 AML cell culture. Importantly, an increase in lysis of auto AML was also detected: 0% day 0, 2.1% unmodified AML culture, 16% LV-CD80/IL2 AML culture. The ratio of Tregs to effector T cells is important for the suppressive function of Tregs. The number of Tregs in the cytotoxicity assays is likely to be lower than that required for a significant suppressive effect to be observed. We next examined the cytotoxicity of NK cells using K562 and unmodified AMLs as targets. NK cells were negatively isolated on days 0 and 7 following either unmodified AML or LV-CD80/IL2 AML cell culture and used as effectors in a 51Cr release assay. In keeping with the changes in NK cell activation receptor expression, we demonstrate a significant increase in NK cell cytotoxicity against both K562 and primary unmodified AMLs. Lysis of K562 increased from 46.7% on day 0 to 90.4% after LV-CD80/IL2 stimulation. Importantly, an increase in lysis of both allo and auto unmodified AMLs was detected following LV-CD80/IL2 AML cell culture. Lysis of allo AMLs increased from a median of 11.8% on day 0, 8.7% following culture with unmodified AML to 20.1% following LV-CD80/IL2 AML cell culture using a low effector: target ratio of just 5:1. Importantly, an increase in lysis of auto AML from 0.4% on day 0, 2.1% with unmodified AML cells to 21.5% following LV-CD80/IL2 AML stimulation was observed. LV-CD80/IL2 AML cells enhance NK cell activation and cytotoxicity against allo and auto unmodified AMLs. Furthermore, cytotoxicity is enhanced even in the presence of Tregs with an increase in Tregs only observed following allo culture. Vaccination of patients with LV-CD80/IL2 AML cells therefore represents a potential strategy to promote T and NK cell cytotoxicity and enhance anti-leukemia immune responses in patients with AML.

scholarly journals WF10 Stimulates NK Cell Cytotoxicity by Increasing LFA-1-Mediated Adhesion to Tumor Cells

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Louisa Kühne ◽  
Mathias Konstandin ◽  
Yvonne Samstag ◽  
Stefan Meuer ◽  
Thomas Giese ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Activation ◽  
Nk Cell ◽  
Killer Cell ◽  
Target Cells ◽  
Dependent Manner ◽  
Cell Cytotoxicity ◽  
Natural Killer Cell Cytotoxicity ◽  
Nk Cell Cytotoxicity

The redox-active chlorite-based drug WF10 (Immunokine) was shown to have modulatory effects on both the innate and adaptive immune systemin vitroandin vivo. Animal studies suggest that WF10 enhances immunity against tumors. One possible explanation for such an effect is that WF10 stimulates natural killer cell cytotoxicity against malignant cells. Here, we show that WF10 regulates human NK cell cytotoxicity in a time-dependent manner, following an S-shaped kinetic with an initial stimulation of activity followed by a decrease in activity relative to the untreated controls. WF10 does not activate NK cells on its own but co-stimulates NK cell activation mediated by different activating receptors. This is mediated by enhancing NK cell adhesion to target cells through promoting the activation of the integrin LFA-1. These data demonstrate a direct effect of WF10 on the cytotoxicity of human NK cells.

scholarly journals NK cell activation in visceral leishmaniasis requires TLR9, myeloid DCs, and IL-12, but is independent of plasmacytoid DCs

2007 ◽  
Vol 204 (4) ◽  
pp. 893-906 ◽  
Author(s):  
Ulrike Schleicher ◽  
Jan Liese ◽  
Ilka Knippertz ◽  
Claudia Kurzmann ◽  
Andrea Hesse ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Nk Cells ◽  
Cell Activation ◽  
Nk Cell ◽  
Dependent Manner ◽  
Cell Cytotoxicity ◽  
Ifn Γ ◽  
Nk Cell Cytotoxicity

Natural killer (NK) cells are sentinel components of the innate response to pathogens, but the cell types, pathogen recognition receptors, and cytokines required for their activation in vivo are poorly defined. Here, we investigated the role of plasmacytoid dendritic cells (pDCs), myeloid DCs (mDCs), Toll-like receptors (TLRs), and of NK cell stimulatory cytokines for the induction of an NK cell response to the protozoan parasite Leishmania infantum. In vitro, pDCs did not endocytose Leishmania promastigotes but nevertheless released interferon (IFN)-α/β and interleukin (IL)-12 in a TLR9-dependent manner. mDCs rapidly internalized Leishmania and, in the presence of TLR9, produced IL-12, but not IFN-α/β. Depletion of pDCs did not impair the activation of NK cells in L. infantum–infected mice. In contrast, L. infantum–induced NK cell cytotoxicity and IFN-γ production were abolished in mDC-depleted mice. The same phenotype was observed in TLR9−/− mice, which lacked IL-12 expression by mDCs, and in IL-12−/− mice, whereas IFN-α/β receptor−/− mice showed only a minor reduction of NK cell IFN-γ expression. This study provides the first direct evidence that mDCs are essential for eliciting NK cell cytotoxicity and IFN-γ release in vivo and demonstrates that TLR9, mDCs, and IL-12 are functionally linked to the activation of NK cells in visceral leishmaniasis.

scholarly journals Role of gamma-secretase in human umbilical-cord derived mesenchymal stem cell mediated suppression of NK cell cytotoxicity

2014 ◽  
Vol 12 (1) ◽  
Author(s):  
Debanjana Chatterjee ◽  
Nicole Marquardt ◽  
Dejene Milkessa Tufa ◽  
Guillaume Beauclair ◽  
Hui Zhi Low ◽  
...  
Keyword(s):  
Stem Cell ◽  
Mesenchymal Stem Cell ◽  
Umbilical Cord ◽  
Nk Cell ◽  
Human Umbilical Cord ◽  
Cell Cytotoxicity ◽  
Gamma Secretase ◽  
Nk Cell Cytotoxicity

Reciprocal regulation of human natural killer cells and macrophages associated with distinct immune synapses

Blood ◽  
2007 ◽  
Vol 109 (9) ◽  
pp. 3776-3785 ◽  
Author(s):  
Shlomo Nedvetzki ◽  
Stefanie Sowinski ◽  
Robert A. Eagle ◽  
James Harris ◽  
Frédéric Vély ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Nk Cells ◽  
Natural Killer ◽  
Cell Activation ◽  
Nk Cell ◽  
Surface Expression ◽  
Cytokine Secretion ◽  
Cell Cytotoxicity ◽  
Nk Cell Cytotoxicity ◽  
High Doses

AbstractNatural killer (NK) cells directly lyse tumor or viral-infected cells but also an important role for NK cell cytotoxicity in regulating the extent of immune responses is emerging. Here, we show that autologous human macrophages activated NK cell proliferation and cytokine secretion, increased expression of activating receptors, and primed NK cell cytotoxicity against susceptible target cells. Ligation of NK cell 2B4, and not NKp30 (known to be important for DC-mediated NK cell activation), is critical for this macrophage-mediated NK cell activation. Reciprocally, however, NK cells regulated macrophage activity by directly killing macrophages stimulated by high doses of LPS. Cytolysis was triggered by NKG2D recognition of stress-inducible class I major histocompatibility complex (MHC)–like ligands on macrophages: high doses of LPS induced transcription and surface expression of ULBP1, ULBP2, and ULBP3 and surface expression of constitutively transcribed MICA. Thus, these data suggest a new function for NK cell cytotoxicity in eliminating overstimulated macrophages. Additionally, these interactions define, for the first time, 2 distinct activating NK cell synapses: lytic and nonlytic. Triggering NK cell proliferation and cytokine secretion, but not cytolysis, specifically associated with synaptic accumulation of macrophage F-actin and NK cell 2B4, while macrophages were killed when NK cell F-actin and macrophage ICAM-1 accumulated around a central cluster of NK cell NKG2D/DAP10.

scholarly journals The effect of IL-2 stimulation and treatment of TRPM3 on channel co-localisation with PIP2 and NK cell function in myalgic encephalomyelitis/chronic fatigue syndrome patients

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Natalie Eaton-Fitch ◽  
Hélène Cabanas ◽  
Stanley du Preez ◽  
Donald Staines ◽  
Sonya Marshall-Gradisnik
Keyword(s):  
Chronic Fatigue Syndrome ◽  
Nk Cells ◽  
Cell Function ◽  
Nk Cell ◽  
Chronic Fatigue ◽  
Signalling Pathways ◽  
Cell Cytotoxicity ◽  
Fatigue Syndrome ◽  
Intracellular Signalling Pathways ◽  
Nk Cell Cytotoxicity

Abstract Background Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a serious multifactorial disorder. The origin remains ambiguous, however reduced natural killer (NK) cell cytotoxicity is a consistent immunological feature of ME/CFS. Impaired transient receptor potential melastatin 3 (TRPM3), a phosphatidylinositol dependent channel, and impaired calcium mobilisation have been implicated in ME/CFS pathology. This investigation aimed to examine the localisation of TRPM3 at the NK cell plasma membrane and co-localisation with phosphatidylinositol 4,5-bisphosphate (PIP2). The effect of IL-2 priming and treatment using pregnenolone sulfate (PregS) and ononetin on TRPM3 co-localisation and NK cell cytotoxicity in ME/CFS patients and healthy controls (HC) was also investigated. Methods NK cells were isolated from 15 ME/CFS patients and 15 age- and sex-matched HC. Immunofluorescent technique was used to determine co-localisation of TRPM3 with the NK cell membrane and with PIP2 of ME/CFS patients and HC. Flow cytometry was used to determine NK cell cytotoxicity. Following IL-2 stimulation and treatment with PregS and ononetin changes in co-localisation and NK cell cytotoxicity were measured. Results Overnight treatment of NK cells with PregS and ononetin resulted in reduced co-localisation of TRPM3 with PIP2 and actin in HC. Co-localisation of TRPM3 with PIP2 in NK cells was significantly reduced in ME/CFS patients compared with HC following priming with IL-2. A significant increase in co-localisation of TRPM3 with PIP2 was reported following overnight treatment with ononetin within ME/CFS patients and between groups. Baseline NK cell cytotoxicity was significantly reduced in ME/CFS patients; however, no changes were observed following overnight incubation with IL-2, PregS and ononetin between HC and ME/CFS patients. IL-2 stimulation significantly enhanced NK cell cytotoxicity in HC and ME/CFS patients. Conclusion Significant changes in co-localisation suggest PIP2-dependent TRPM3 function may be impaired in ME/CFS patients. Stimulation of NK cells with IL-2 significantly enhanced cytotoxic function in ME/CFS patients demonstrating normal function compared with HC. A crosstalk exists between IL-2 and TRPM3 intracellular signalling pathways which are dependent on Ca2+ influx and PIP2. While IL-2R responds to IL-2 binding in vitro, Ca2+ dysregulation and impaired intracellular signalling pathways impede NK cell function in ME/CFS patients.

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