CX3CR1 expression defines 2 KLRG1+ mouse NK-cell subsets with distinct functional properties and positioning in the bone marrow

Abstract During development in the bone marrow (BM), NK-cell positioning within specific niches can be influenced by expression of chemokine or adhesion receptors. We previously demonstrated that the maintenance in the BM of selected NK-cell subsets is regulated by the CXCR4/CXCL12 axis. In the present study, we showed that CX3CR1 is prevalently expressed on KLRG1+ NK cells, a subset considered terminally differentiated. Two KLRG1+ NK-cell populations endowed with distinct homing and functional features were defined according to CX3CR1 expression. In the BM, KLRG1+/CX3CR1− NK cells were mainly positioned into parenchyma, while KLRG1+/CX3CR1+ NK cells exhibited reduced CXCR4 expression and were preferentially localized in the sinusoids. We also showed that α4 integrin plays a pivotal role in the maintenance of NK cells in the BM sinusoids and that α4 neutralization leads to strong reduction of BM KLRG1+/CX3CR1+ NK cells. Moreover, we found that KLRG1+/CX3CR1+ cells originate from KLRG1+/CX3CR1− NK-cell population and display impaired capability to produce IFN-γ and to lyse YAC-1 target cells on cytokine stimulation. Altogether, our findings show that CX3CR1 represents a marker of a KLRG1+ NK-cell population with unique properties that can irreversibly differentiate from the KLRG1+/CX3CR1− NK cells during steady state conditions.

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Chlamydia psittaci-Infected Dendritic Cells Communicate with NK Cells via Exosomes To Activate Antibacterial Immunity

Infection and Immunity ◽

10.1128/iai.00541-19 ◽

2019 ◽

Vol 88 (1) ◽

Author(s):

Nadine Radomski ◽

Axel Karger ◽

Kati Franzke ◽

Elisabeth Liebler-Tenorio ◽

Rico Jahnke ◽

...

Keyword(s):

Dendritic Cells ◽

Nk Cells ◽

Nk Cell ◽

Early Response ◽

Chlamydia Psittaci ◽

Target Cells ◽

Necrosis Factor Alpha ◽

Content Type ◽

Host Cell Death ◽

Ifn Γ

ABSTRACT Dendritic cells (DCs) and natural killer (NK) cells are critically involved in the early response against various bacterial microbes. Functional activation of infected DCs and NK cell-mediated gamma interferon (IFN-γ) secretion essentially contribute to the protective immunity against Chlamydia. How DCs and NK cells cooperate during the antichlamydial response is not fully understood. Therefore, in the present study, we investigated the functional interplay between Chlamydia-infected DCs and NK cells. Our biochemical and cell biological experiments show that Chlamydia psittaci-infected DCs display enhanced exosome release. We find that such extracellular vesicles (referred to as dexosomes) do not contain infectious bacterial material but strongly induce IFN-γ production by NK cells. This directly affects C. psittaci growth in infected target cells. Furthermore, NK cell-released IFN-γ in cooperation with tumor necrosis factor alpha (TNF-α) and/or dexosomes augments apoptosis of both noninfected and infected epithelial cells. Thus, the combined effect of dexosomes and proinflammatory cytokines restricts C. psittaci growth and attenuates bacterial subversion of apoptotic host cell death. In conclusion, this provides new insights into the functional cooperation between DCs, dexosomes, and NK cells in the early steps of antichlamydial defense.

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Ex Vivo Activated Natural Killer (NK) Cells from Myeloma Patients Kill Autologous Myeloma and Killing Is Enhanced by Elotuzumab

Blood ◽

10.1182/blood.v112.11.3666.3666 ◽

2008 ◽

Vol 112 (11) ◽

pp. 3666-3666

Author(s):

Tarun K. Garg ◽

Susann Szmania ◽

Jumei Shi ◽

Katie Stone ◽

Amberly Moreno-Bost ◽

...

Keyword(s):

Bone Marrow ◽

Cell Therapy ◽

Nk Cells ◽

Nk Cell ◽

Ex Vivo ◽

K562 Cells ◽

Scid Mice ◽

Target Cells ◽

Recent Trial ◽

Nk Cell Therapy

Abstract Immune-based therapies may improve outcome for multiple myeloma (MM) by eradicating chemo-resistant disease. Our recent trial utilizing IL2 activated, killer immunoglobulin-like receptor-ligand mismatched NK cell transfusions from haplo-identical donors yielded (n) CR in 50% of patients. Unfortunately, after NK cell therapy, 2/10 patients had progressive disease, and the median duration of response for the other 8/10 patients was only 105 days (range 58–593). This may have been due to an insufficient dose of alloreactive NK cells and early rejection. Furthermore, appropriate donors were identified for only 30% of otherwise eligible patients. We therefore investigated whether NK cells from MM patients could be expanded and activated to kill autologous MM. We then examined whether pre-treatment of MM cell targets with elotuzumab, a humanized antibody to the MM tumor antigen CS1, could further enhance NK cell-mediated lysis. PBMC from 5 MM patients were co-cultured for 14 days with irradiated K562 cells transfected with 4-1BBL and membrane bound IL15 in the presence of IL2 (300U/ml) as previously described (Imai et al, Blood2005;106:376–383). The degree of NK cell expansion, NK immunophenotype, and ability to kill MM (4 hour 51Cr release assays) were assessed. To determine the ability of ex vivo expanded NK cells to traffic to bone marrow, activated NK cells were injected into the tail vein of NK cell depleted NOD-SCID mice, which were then sacrificed after 48 hours. Flow cytometry for human CD45, CD3, and CD56 was performed on cells from blood, marrow and spleen. There was an average 64-fold expansion of NK cells (range: 8–200) after 2 weeks of co-culture with K562 transfectants. Expansion of T cells was not observed. The NK cell activating receptor NKG2D, and natural cytotoxicity receptors NKp30, NKp44, and NKp46 were up-regulated following the expansion. Expanded NK cells were able to kill autologous MM (E:T ratio 10:1, average 31%, range 22–41%), whereas resting NK cells did not. Pretreatment of autologous MM cells with elotuzumab increased the activated NK cell-mediated killing by 1.7-fold over target cells pretreated with an isotype control antibody. This level of killing was similar to that of the highly NK kill-sensitive cell line K562 (Figure). Autologous PHA blasts and CD34+ stem cells were not killed. Activated human NK cells were detectable in the bone marrow of NOD-SCID mice 48 hours after injection. Ex vivo activation of NK cells from MM patients with K562 transfectants can induce killing of autologous MM and produce large numbers of NK cells for potential therapy. The addition of elotuzumab to activated NK cell therapy enhances anti-MM effects by ADCC thus invoking an additional NK cell-mediated mechanism of MM killing. Importantly, ex vivo activated NK cells traffic to the bone marrow in mice. Autologous NK cell therapy eliminates the issues related to allo-donor availability and early NK cell rejection, and could provide an option for patients refractory to chemotherapy agents. Figure Figure

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

Blood ◽

10.1182/blood.v128.22.1764.1764 ◽

2016 ◽

Vol 128 (22) ◽

pp. 1764-1764 ◽

Cited By ~ 1

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.

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Natural killer (NK) cell activation, cytokine production, and cytotoxicity in human PBMC/myeloma cell co-culture exposed to elotuzumab (Elo) alone or in combination with lenalidomide (Len).

Journal of Clinical Oncology ◽

10.1200/jco.2012.30.15_suppl.8087 ◽

2012 ◽

Vol 30 (15_suppl) ◽

pp. 8087-8087 ◽

Cited By ~ 2

Author(s):

Balaji Balasa ◽

Rui Yun ◽

Nicole Belmar ◽

Gary Starling ◽

Audie Rice

Keyword(s):

Nk Cells ◽

Cell Activation ◽

Nk Cell ◽

Myeloma Cell ◽

Cell Killing ◽

Cell Counting ◽

Target Cells ◽

Human Pbmc ◽

Myeloma Cells ◽

Ifn Γ

8087 Background: Elo is a monoclonal IgG1 antibody targeting CS1, a cell surface glycoprotein highly expressed on >95% of myeloma cells. In preclinical models Elo exerts anti-myeloma activity via NK cell-mediated antibody-dependent cellular cytotoxicity. Len is an immunomodulatory agent that may activate NK cells. The combination of Elo + Len synergistically enhanced anti-tumor activity in myeloma xenograft models. We investigated the mechanism of enhancing NK cell activation and myeloma cell killing with Elo + Len. Methods: Human PBMC/OPM-2 co-cultures were treated for 24-72h with Elo, Len, or Elo + Len. Activation markers and adhesion receptors were evaluated by flow cytometry. Cytokines were measured by Luminex and ELISpot assays. Cytotoxicity was assessed by cell counting. Results: Elo + Len increased IFN-γ secretion significantly more than Elo or Len alone. IFN-γ elevates ICAM-1 expression, and ICAM-1 surface expression on OPM-2 target cells increased synergistically with Elo + Len. Elo, Elo + Len but not Len increased expression of CD25 (IL-2Rα) on NK cells. Len increased the levels of IL-2, but those were decreased in the presence of Elo due to increased consumption by CD25 expressing NK cells. Blocking uptake of IL-2 with anti-CD25 resulted in higher IL-2 levels than with Len. ELISpot assays confirmed that Elo + Len significantly increased the number of IL-2-producing cell colonies compared with Elo or Len. Elo induced NK dependent myeloma cell killing, and the effect was significantly higher with Elo + Len. Conclusions: Elo alone activated NK cells and mediated the killing of myeloma cells in PBMC/OPM-2 co-cultures. Elo + Len synergistically enhanced myeloma cell killing and increased expression/production of IFN-γ, ICAM-1, IL-2, and CD25. [Table: see text]

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IL-15 and IL-2 oppositely regulate expression of the chemokine receptor CX3CR1

Blood ◽

10.1182/blood-2003-03-0946 ◽

2003 ◽

Vol 102 (10) ◽

pp. 3494-3503 ◽

Cited By ~ 35

Author(s):

Jana Barlic ◽

Joan M. Sechler ◽

Philip M. Murphy

Keyword(s):

Bone Marrow ◽

Nk Cells ◽

Chemokine Receptor ◽

Mononuclear Cells ◽

Nk Cell ◽

Negative Regulator ◽

Mouse Bone Marrow ◽

Primary Mouse ◽

Receptor Cx3cr1 ◽

Cx3cr1 Expression

AbstractThe chemokine receptor CX3CR1 (CX3C chemokine receptor 1) is expressed in mouse blood on natural killer (NK) cells and on monocytes. Because interleukin-15 (IL-15) is an essential cytokine for NK cell development and maintenance, we hypothesized that it may induce CX3CR1 expression on this cell type. In contrast, we found that in primary mouse bone marrow-derived NK cells IL-15 specifically inhibited CX3CR1 protein and mRNA accumulation, whereas the related cytokine IL-2 did not inhibit but instead increased CX3CR1 expression. Consistent with this finding, intravenous injection of a single dose of recombinant IL-15 into C57BL/6 mice decreased steady-state CX3CR1 levels 24 hours after injection in freshly isolated peripheral blood mononuclear cells (PBMCs), splenocytes, and bone marrow cells, and treatment of mouse PBMCs with IL-15 in vitro inhibited CX3CL1 (ligand for CX3CR1)-induced chemotaxis. These data suggest that IL-15 may be a negative regulator of innate immunity by inhibiting CX3CR1 expression. These data also suggest that IL-15 inhibition of CX3CR1 may subvert potential cell immunotherapy strategies in which IL-15 is used to expand NK cell populations in vivo or ex vivo. Finally, our results provide additional evidence for differential signaling by IL-2 and IL-15, despite usage of common βγc receptor chains. (Blood. 2003;102:3494-3503)

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Tim-3 expression and function in natural killer cells from advanced melanoma patients.

Journal of Clinical Oncology ◽

10.1200/jco.2012.30.15_suppl.8571 ◽

2012 ◽

Vol 30 (15_suppl) ◽

pp. 8571-8571

Author(s):

Ines Esteves Domingues Pires Da Silva ◽

Sonia Jimenez-Baranda ◽

Anne Gallois ◽

Vijay Kuchroo ◽

Iman Osman ◽

...

Keyword(s):

Nk Cells ◽

Nk Cell ◽

Advanced Melanoma ◽

Target Cells ◽

Cell Cytotoxicity ◽

Healthy Donors ◽

Melanoma Patients ◽

Ifn Γ ◽

Nk Cell Cytotoxicity ◽

And Function

8571 Background: The concept of CD8+ T cell exhaustion in the context of metastatic cancer has been reinforced by the recent success of immunotherapies targeting the exhaustion markers CTLA-4 and PD-1 in advanced melanoma. T-cell immunoglobulin 3 (Tim-3), another exhaustion marker, is also expressed in natural killer (NK) cells, however its role is still unknown. Recent reports have shown that NK cells, innate immune cells that eliminate tumors through cytotoxicity and IFN-g production, are functionally impaired in advanced melanoma patients, although no receptor has been linked with that phenotype so far. In this study, we characterize the role of Tim-3 in NK cells, particularly in the presence of its natural ligand, Galectin-9 (Gal-9), that is known to be expressed/secreted by some tumor cells including melanoma. Methods: We compared 20 advanced melanoma donors NK cells with 40 healthy donors NK cells as it relates to Tim-3 expression (by flow cytometry) and function (cytotoxicity, IFN-γ production and proliferation). NK cells cytotoxicity was measured by lamp-1 expression, and two different target cells were used: i) K562 cells (Gal-9-) and ii) Gmel Gal-9+ and Gmel Gal-9- sorted melanoma cells. Proliferation was quantified by CFSE after 6 days in the presence of rhIL-2. Recombinant rhGal9 effect was tested in cytotoxicity and IFN-γ production. Results: Melanoma patients NK cells express higher levels of Tim-3 compared to healthy donors NK cells (p<0.05). Melanoma patients NK cells have a defect in cytotoxicity, proliferation and IFN-γ production. Tim-3 expression by itself (without engagement of specific ligands) does not negatively affect NK cell functions (p<0.05). However, when rhGal9 is added to the system, a decrease in NK cell cytotoxicity and IFN-γ production (p<0.05) was observed. Finally, the expression of Gal-9 by the target cells induces a defect in NK cell cytotoxicity (Gmel Gal-9+ vs Gmel Gal-9-). Conclusions: These data suggest that advanced melanoma patients NK cells are exhausted, although it still remains unclear if Tim-3 is involved in this phenotype. In addition,the expression/secretion of Galectin-9, immunosuppressive for NK cells, may be a possible mechanism for tumors to evade immune surveillance.

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The FLT3-Inhibitors Midostaurin, Sunitinib, Sorafenib, and TKI258 Differentially Affect NK Cell-Mediated Immunesurveillance of Acute Myeloid Leukemia.

Blood ◽

10.1182/blood.v114.22.3785.3785 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3785-3785

Author(s):

Julia Salih ◽

Lothar Kanz ◽

Helmut R Salih ◽

Matthias Krusch

Keyword(s):

Nk Cells ◽

Myeloid Leukemia ◽

Nk Cell ◽

Immune Surveillance ◽

Leukemia Cells ◽

Target Cells ◽

Cell Reactivity ◽

Flt3 Inhibitors ◽

Ifn Γ

Abstract Abstract 3785 Poster Board III-721 FLT3 is a receptor tyrosine kinase with an important role in hematopoietic progenitor cell survival and proliferation. The discovery of internal tandem duplication mutations (ITD) in FLT3 was a major breakthrough in understanding the role of abnormally activated FLT3 in myeloid transformation. Between 15% and 34% of AML patients show FLT3-ITD mutations, and thus the inhibition of FLT3 in combination with chemotherapeutic agents may be a promising stragety in the treatment of Acute Myeloid Leukemia (AML). Several protein kinase inhibitors (PKI) targeting FLT3 like e.g. Midostaurin, Sunitinib, Sorafenib, and TKI258 are currently under preclinical and/or clinical evaluation (http://clinicaltrials.gov/ct2/results?term=AML+and+FLT3). Since those PKI, besides targeting their eponymous enzyme FLT3, also inhibit signaling via other molecules they may impair the effector function of various components of anti-tumor immunity. NK cells as part of the innate immune system play an important role in the immune surveillance of tumors due to their ability to directly kill target cells and to shape adaptive immune responses by secreting cytokines like IFN-γ. Clinical evidence for the particularly important role of NK cells in leukemia has recently been provided by studies of haploidentical stem cell transplantation (Ruggeri et al., Science 2002). We report here that CD107a expression as a surrogate marker for degranulation of NK cells within PBMC is inhibited by pharmacological concentrations of Sorafenib (10μg/ml) and Midostaurin (2μg/ml), but not by Sunitinib (200ng/ml) and TKI258 (125ng/ml). In line, pharmacological concentrations of Sunitinib and TKI258 did not affect NK cell cytotoxicity and IFN-γ production in cocultures with leukemia cells. Sorafenib and Midostaurin caused a clear concentration-dependent inhibition of NK cell cytokine production in response to target cells both in resting and in IL-2 activated state (92% and 66%, respectively at plasma peak levels). Furthermore, pharmacological concentrations of Sorafenib and Midostaurin also reduced lysis of leukemia cells by NK cells (54% and 58%, respectively, E:T ratio 10:1) and thus generally compromised NK cell reactivity. Analysis of NK cell signaling revealed that Sorafenib, but not Midostaurin decreased phosphorylation of PI3K and ERK which are important regulators of NK cell reactivity. Thus, Midostaurin inhibits yet undefined signaling events which are crucial for NK effector functions, but are independent of the “classical” PI3K – Rac – PAK – MEK – ERK pathway and are presently under study. Moreover, in light of the important role of NK cells in the immune surveillance of leukemia and the differential influence of clinically used FLT3-inhibitors on NK cell functions our data indicate that the choice and dosing of the most suitable compound in the treatment of AML requires further characterization and careful consideration. Disclosures: No relevant conflicts of interest to declare.

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Tumor growth impedes natural-killer-cell maturation in the bone marrow

Blood ◽

10.1182/blood-2005-11-4535 ◽

2006 ◽

Vol 108 (1) ◽

pp. 246-252 ◽

Cited By ~ 50

Author(s):

John O. Richards ◽

Xing Chang ◽

Bradley W. Blaser ◽

Michael A. Caligiuri ◽

Pan Zheng ◽

...

Keyword(s):

Bone Marrow ◽

Tumor Growth ◽

Nk Cells ◽

Natural Killer ◽

Bone Marrow Cells ◽

Nk Cell ◽

Killer Cell ◽

Cell Development ◽

Functional Maturation ◽

Ifn Γ

Natural-killer (NK)-cell dysfunction and IFN-γ deficiencies have been associated with increased incidence of both malignancy and infection. The immunologic basis of NK-cell defects in cancer-bearing hosts has not been extensively studied. Here, we demonstrate that multiple lineages of tumors, including thymoma, breast cancer, colon cancer, and melanoma cell lines, interrupt functional maturation during NK-cell development in the bone marrow. The immature NK cells in the periphery of tumor-bearing mice had impaired IFN-γ production but seemingly normal cytotoxicity. T cells are not involved in this NK maturation arrest, because T-cell depletion did not restore NK-cell development. Moreover, the extent of tumor-cell infiltration into the bone marrow does not correlate with defective NK maturation. Interestingly, the defect was associated with a significant reduction in the IL-15Rα+ cells in the non-T, non-NK compartment of bone marrow cells and restored by overexpression of IL-15. Our data demonstrate that tumor growth can impede functional maturation of NK cells, most likely by interrupting the requisite IL-15 signaling pathway. (Blood. 2006;108:246-252)

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Natural Killer Cell Subpopulations and Inhibitory Receptor Dynamics in Myelodysplastic Syndromes and Acute Myeloid Leukemia

Frontiers in Immunology ◽

10.3389/fimmu.2021.665541 ◽

2021 ◽

Vol 12 ◽

Author(s):

Vlad Andrei Cianga ◽

Lydia Campos Catafal ◽

Petru Cianga ◽

Mariana Pavel Tanasa ◽

Mohamad Cherry ◽

...

Keyword(s):

Bone Marrow ◽

Immune Response ◽

Nk Cells ◽

Natural Killer ◽

Nk Cell ◽

Expression Patterns ◽

Receptor Expression ◽

Cell Maturation ◽

Target Cells ◽

Cell Subpopulations

Natural killer (NK) cells are key innate immunity effectors that play a major role in malignant cell destruction. Based on expression patterns of CD16, CD56, CD57, and CD94, three distinct NK cell maturation stages have been described, which differ in terms of cytokine secretion, tissue migration, and the ability to kill target cells. Our study addressed NK cell maturation in bone marrow under three conditions: a normal developmental environment, during pre-leukemic state (myelodysplastic syndrome, MDS), and during leukemic transformation (acute myeloblastic leukemia, AML). In this study, we used a new tool to perform multicolor flow cytometry data analysis, based on principal component analysis, which allowed the unsupervised, accurate discrimination of immature, mature, and hypermature NK subpopulations. An impaired NK/T cell distribution was observed in the MDS bone marrow microenvironment compared with the normal and AML settings, and a phenotypic shift from the mature to the immature state was observed in NK cells under both the MDS and AML conditions. Furthermore, an impaired NK cell antitumor response, resulting in changes in NK cell receptor expression (CD159a, CD158a, CD158b, and CD158e1), was observed under MDS and AML conditions compared with the normal condition. The results of this study provide evidence for the failure of this arm of the immune response during the pathogenesis of myeloid malignancies. NK cell subpopulations display a heterogeneous and discordant dynamic on the spectrum between normal and pathological conditions. MDS does not appear to be a simple, intermediate stage but rather serves as a decisive step for the mounting of an efficient or ineffective immune response, leading to either the removal of the tumor cells or to malignancy.

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CD38 contributes to human natural killer cell responses through a role in immune synapse formation

10.1101/349084 ◽

2018 ◽

Cited By ~ 7

Author(s):

Mathieu Le Gars ◽

Christof Seiler ◽

Alexander W. Kay ◽

Nicholas L. Bayless ◽

Elsa Sola ◽

...

Keyword(s):

Nk Cells ◽

Natural Killer ◽

Tumor Cells ◽

Synapse Formation ◽

Cell Function ◽

Nk Cell ◽

Critical Role ◽

Target Cells ◽

Immune Synapse ◽

Ifn Γ

AbstractNatural killer (NK) cells use a diverse array of activating and inhibitory surface receptors to detect threats and provide an early line of defense against viral infections and cancer. Here, we demonstrate that the cell surface protein CD38 is a key human NK cell functional receptor through a role in immune synapse formation. CD38 expression marks a mature subset of human NK cells with a high functional capacity. NK cells expressing high levels of CD38 display enhanced killing and IFN-γ secretion in response to influenza virus-infected and tumor cells. Inhibition of CD38 enzymatic activity does not influence NK cell function, but blockade of CD38 and its ligand CD31 abrogates killing and IFN-γ expression in response to influenza-infected cells. Blockade of CD38 on NK cells similarly inhibits killing of tumor cells. CD38 localizes and accumulates at the immune synapse between NK cells and their targets, and blocking CD38 severely abrogates the ability of NK cells to form conjugates and immune synapses with target cells. Thus, CD38 plays a critical role in NK cell immune synapse formation. These findings open new avenues in immunotherapeutic development for cancer and infection by revealing a critical role for CD38 in NK cell function.

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