Targeting the Tumor Evasion Interaction of NKG2A and Its Ligand HLA-E Increases Natural-Killer Cell Activity in Chronic Lymphocytic Leukemia

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1289-1289 ◽  
Author(s):  
Emily McWilliams ◽  
Jennifer M Mele ◽  
Faraz Fiazuddin ◽  
Carolyn Cheney ◽  
Natarajan Muthusamy ◽  
...  
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Nk Cells ◽  
Natural Killer ◽  
Cell Activation ◽  
Nk Cell ◽  
Lymphocytic Leukemia ◽  
Target Cells ◽  
Cell Dysfunction ◽  
Direct Cytotoxicity

Abstract Chronic Lymphocytic Leukemia (CLL) represents the most frequent adult leukemia, and remains incurable with current standard therapies. Natural Killer (NK) cell count is predictive of CLL disease progression and their dysfunction in mediating cytokine release and direct or antibody dependent cellular cytotoxicity (ADCC) against CLL B-cells is well documented. Detailed mechanistic insight into the etiology of NK-cell dysfunction in CLL patients is currently lacking. CLL B-cells overexpress HLA-E, the natural ligand for heterodimer CD94/NKG2A receptor complex that is expressed on the surface of NK cells, and this interaction suppresses NK cell activation. While NKG2A/CD94/HLA-E interaction is known to assist NK cells in recognizing "self", tumor cells utilize this mechanism to evade effector cell killing. Utilizing a novel anti-NKG2A monoclonal blocking antibody (mab) we explored the in vitro preclinical activity of targeting the NKG2A receptor, and the NKG2A/HLA-E interaction as a mechanism of tumor evasion in patients with CLL. We hypothesized that limiting the interaction of HLA-E/NKG2A will reverse NK cell anergy and result in increased direct cytotoxicity of CLL cells. Our results confirm the over expression of HLA-E on CLL B-cells and demonstrate NKG2A expression on CD16+ NK cells from CLL patients. Next, we examined the effect of anti-NKG2A mab on NK cell direct cytotoxicity. Treatment of NK cells, from both healthy donor and CLL patients, with anti-NKG2A mab increased direct cytotoxicity over isotype control on targets at various effector to target ratios of 25:1 (54% vs. 46%, p< 0.05, n= 12), 12:1 (43% vs. 35%, p<0.05, n=14), and 6:1 (31% vs. 23%, p<0.05, n= 12, for anti-NKG2A mediated cytotoxicity vs isotype mediated cytotoxicity respectively). These results were also validated with HLA-E over and underexpressing target cells. Fc-gamma receptor blocking experiments were also performed to confirm the specificity of the interaction. Further studies are being performed to confirm the specific activity of the antibody including its ability to modulate NK cell activation, enhance ADCC, and the impact of anti-NKG2A therapy for reversing ibrutinib mediated NK-cell dysfunction. This work has laid the foundation for the clinical utility of this reagent in patients with relapsed CLL in combination with ibrutinib. Disclosures No relevant conflicts of interest to declare.

scholarly journals Battle of Thermopylae: 300 Spartans (natural killer cells plus obinutuzumab) versus the immortal warriors (chronic lymphocytic leukemia cells) of Xerxes’ army

2019 ◽  
Vol 5 (10) ◽  
pp. FSO425
Author(s):  
Ricardo García-Muñoz ◽  
María-Josefa Nájera ◽  
Jesús Feliu ◽  
Judith Antón-Remírez ◽  
Enrique Ramalle-Gómara ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Nk Cells ◽  
Natural Killer ◽  
Peripheral Blood ◽  
Nk Cell ◽  
Killer Cell ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Lymphokine Activated Killer Cells ◽  
Killer Cells

Aim: To analyze the effects of subcutaneous or intravenous rituximab + lymphokine-activated killer cells, obinutuzumab or ibrutinib on natural killer (NK) cell levels in chronic lymphocytic leukemia and follicular lymphoma patients. Patients & methods: The distribution of peripheral blood NK cells of 31 patients was analyzed by flow cytometry. Results: We detected a decrease of NK cells in peripheral blood below normal range after obinutuzumab treatment. During maintenance treatment with subcutaneous rituximab, an NK cell reduction was less pronounced than after intravenous rituximab treatment, despite lymphokine-activated killer cell infusions. Conclusion: After one dose of obinutuzumab, each NK cell in peripheral blood destroys 25 leukemic cells.

scholarly journals Patients with a deficiency of natural killer cell activity lack the VEP13-positive lymphocyte subpopulation

Blood ◽  
1985 ◽  
Vol 65 (1) ◽  
pp. 65-70 ◽  
Author(s):  
HW Ziegler-Heitbrock ◽  
H Rumpold ◽  
D Kraft ◽  
C Wagenpfeil ◽  
R Munker ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Natural Killer Cell Activity ◽  
Killer Cell ◽  
Cell Activity ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Target Cells ◽  
Nk Cell Activity

Many patients with B-type chronic lymphocytic leukemia (CLL) exhibit a profound defect in their natural killer (NK) cell activity, the basis of which is still obscure. Hence, we analyzed the NK cells from peripheral blood samples from 11 patients with CLL for phenotype and function, after removal of the leukemic cells with a monoclonal antibody (BA-1) plus complement. Phenotypic analysis of these nonleukemic cells with monoclonal antibodies (MoAbs) against NK cells revealed that the CLL patients had higher percentages of HNK-1-positive cells (23.5% compared to controls with 14.7%). In contrast, VEP13- positive cells were absent or low in seven patients (0.8% compared to controls with 11.2%) and normal in four patients (10.5%). When testing NK cell activities against K562 or MOLT 4 target cells, patients with no or minimal numbers of VEP13-positive cells were found to be deficient, while patients with normal percentages of VEP13-positive cells had NK cell activity comparable to controls. Isolation by fluorescence-activated cell sorter of HNK-1-positive cells from patients lacking VEP13-positive cells and NK cell activity indicated that the majority of the HNK-1-positive cells in these patients had the large granular lymphocyte morphology that is characteristic of NK cells. Thus, the deficiency of NK cell activity in CLL patients appears to result from the absence of cells carrying the VEP13 marker.

scholarly journals Identification and Molecular Characterization of Nkp30, a Novel Triggering Receptor Involved in Natural Cytotoxicity Mediated by Human Natural Killer Cells

1999 ◽  
Vol 190 (10) ◽  
pp. 1505-1516 ◽  
Author(s):  
Daniela Pende ◽  
Silvia Parolini ◽  
Anna Pessino ◽  
Simona Sivori ◽  
Raffaella Augugliaro ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Cell Activation ◽  
Nk Cell ◽  
Immunoglobulin Superfamily ◽  
Target Cells ◽  
Natural Cytotoxicity ◽  
Human Natural Killer Cells ◽  
Nk Cytotoxicity

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

scholarly journals Mast Cells and Natural Killer Cells—A Potentially Critical Interaction

Viruses ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 514 ◽  
Author(s):  
Liliana Portales-Cervantes ◽  
Bassel Dawod ◽  
Jean S. Marshall
Keyword(s):  
Mast Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Host Defense ◽  
Cell Activation ◽  
Nk Cell ◽  
Mast Cell Activation ◽  
Target Cells ◽  
Effector Functions ◽  
Mucosal Surfaces

Natural killer (NK) cells play critical roles in host defense against infectious agents or neoplastic cells. NK cells provide a rapid innate immune response including the killing of target cells without the need for priming. However, activated NK cells can show improved effector functions. Mast cells are also critical for early host defense against a variety of pathogens and are predominately located at mucosal surfaces and close to blood vessels. Our group has recently shown that virus-infected mast cells selectively recruit NK cells and positively modulate their functions through mechanisms dependent on soluble mediators, such as interferons. Here, we review the possible consequences of this interaction in both host defense and pathologies involving NK cell and mast cell activation.

scholarly journals Screening for Active Compounds Targeting Human Natural Killer Cell Activation Identifying Daphnetin as an Enhancer for IFN-γ Production and Direct Cytotoxicity

2021 ◽  
Vol 12 ◽  
Author(s):  
Baige Yao ◽  
Qinglan Yang ◽  
Yao Yang ◽  
Yana Li ◽  
Hongyan Peng ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Cell Activation ◽  
Nk Cell ◽  
Killer Cell ◽  
Mtor Signaling ◽  
Human Natural Killer Cell ◽  
Active Compounds ◽  
Direct Cytotoxicity ◽  
Ifn Γ

Natural killer (NK) cells are a potent weapon against tumor and viral infection. Finding active compounds with the capacity of enhancing NK cell effector functions will be effective to develop new anti-cancer drugs. In this study, we initially screened 287 commercially available active compounds by co-culturing with peripheral blood mononuclear cells (PBMCs). We found that five compounds, namely, Daphnetin, MK-8617, LW6, JIB-04, and IOX1, increased the IFN-γ+ NK cell ratio in the presence of IL-12. Further studies using purified human primary NK cells revealed that Daphnetin directly promoted NK cell IFN-γ production in the presence of IL-12 but not IL-15, while the other four compounds acted on NK cells indirectly. Daphnetin also improved the direct cytotoxicity of NK cells against tumor cells in the presence of IL-12. Through RNA-sequencing, we found that PI3K-Akt-mTOR signaling acted as a central pathway in Daphnetin-mediated NK cell activation in the presence of IL-12. This was further confirmed by the finding that both inhibitors of PI3K-Akt and its main downstream signaling mTOR, LY294002, and rapamycin, respectively, can reverse the increase of IFN-γ production and cytotoxicity in NK cells promoted by Daphnetin. Collectively, we identify a natural product, Daphnetin, with the capacity of promoting human NK cell activation via PI3K-Akt-mTOR signaling in the presence of IL-12. Our current study opens up a new potential application for Daphnetin as a complementary immunomodulator for cancer treatments.

scholarly journals CD19 targeting of chronic lymphocytic leukemia with a novel Fc-domain–engineered monoclonal antibody

Blood ◽  
2010 ◽  
Vol 115 (6) ◽  
pp. 1204-1213 ◽  
Author(s):  
Farrukh T. Awan ◽  
Rosa Lapalombella ◽  
Rossana Trotta ◽  
Jonathan P. Butchar ◽  
Bo Yu ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Cell Activation ◽  
Nk Cell ◽  
Specific Antigen ◽  
Strong Support ◽  
Lymphocytic Leukemia ◽  
Extracellular Signal ◽  
Direct Cytotoxicity

Abstract CD19 is a B cell–specific antigen expressed on chronic lymphocytic leukemia (CLL) cells but to date has not been effectively targeted with therapeutic monoclonal antibodies. XmAb5574 is a novel engineered anti-CD19 monoclonal antibody with a modified constant fragment (Fc)–domain designed to enhance binding of FcγRIIIa. Herein, we demonstrate that XmAb5574 mediates potent antibody-dependent cellular cytotoxicity (ADCC), modest direct cytotoxicity, and antibody-dependent cellular phagocytosis but not complement-mediated cytotoxicity against CLL cells. Interestingly, XmAb5574 mediates significantly higher ADCC compared with both the humanized anti-CD19 nonengineered antibody it is derived from and also rituximab, a therapeutic antibody widely used in the treatment of CLL. The XmAb5574-dependent ADCC is mediated by natural killer (NK) cells through a granzyme B–dependent mechanism. The NK cell–mediated cytolytic and secretory function with XmAb5574 compared with the nonengineered antibody is associated with enhanced NK-cell activation, interferon production, extracellular signal-regulated kinase phosphorylation downstream of Fcγ receptor, and no increased NK-cell apoptosis. Notably, enhanced NK cell–mediated ADCC with XmAb5574 was enhanced further by lenalidomide. These findings provide strong support for further clinical development of XmAb5574 as both a monotherapy and in combination with lenalidomide for the therapy of CLL and related CD19+ B-cell malignancies.

scholarly journals Gntb-A, a Novel Sh2d1a-Associated Surface Molecule Contributing to the Inability of Natural Killer Cells to Kill Epstein-Barr Virus–Infected B Cells in X-Linked Lymphoproliferative Disease

2001 ◽  
Vol 194 (3) ◽  
pp. 235-246 ◽  
Author(s):  
Cristina Bottino ◽  
Michela Falco ◽  
Silvia Parolini ◽  
Emanuela Marcenaro ◽  
Raffaella Augugliaro ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Epstein Barr Virus ◽  
Cell Activation ◽  
Nk Cell ◽  
Lymphoproliferative Disease ◽  
Sh2 Domain ◽  
Target Cells ◽  
Barr Virus ◽  
Epstein Barr

In humans, natural killer (NK) cell function is regulated by a series of receptors and coreceptors with either triggering or inhibitory activity. Here we describe a novel 60-kD glycoprotein, termed NTB-A, that is expressed by all human NK, T, and B lymphocytes. Monoclonal antibody (mAb)-mediated cross-linking of NTB-A results in the induction of NK-mediated cytotoxicity. Similar to 2B4 (CD244) functioning as a coreceptor in the NK cell activation, NTB-A also triggers cytolytic activity only in NK cells expressing high surface densities of natural cytotoxicity receptors. This suggests that also NTB-A may function as a coreceptor in the process of NK cell activation. Molecular cloning of the cDNA coding for NTB-A molecule revealed a novel member of the immunoglobulin superfamily belonging to the CD2 subfamily. NTB-A is characterized, in its extracellular portion, by a distal V-type and a proximal C2-type domain and by a cytoplasmic portion containing three tyrosine-based motifs. NTB-A undergoes tyrosine phosphorylation and associates with the Src homology 2 domain–containing protein (SH2D1A) as well as with SH2 domain–containing phosphatases (SHPs). Importantly, analysis of NK cells derived from patients with X-linked lymphoproliferative disease (XLP) showed that the lack of SH2D1A protein profoundly affects the function not only of 2B4 but also of NTB-A. Thus, in XLP-NK cells, NTB-A mediates inhibitory rather than activating signals. These inhibitory signals are induced by the interaction of NTB-A with still undefined ligands expressed on Epstein-Barr virus (EBV)-infected target cells. Moreover, mAb-mediated masking of NTB-A can partially revert this inhibitory effect while a maximal recovery of target cell lysis can be obtained when both 2B4 and NTB-A are simultaneously masked. Thus, the altered function of NTB-A appears to play an important role in the inability of XLP-NK cells to kill EBV-infected target cells.

Lenalidomide Treatment Enhances Immunological Synapse Formation of Cord Blood Natural Killer Cells with B Cells Derived From Chronic Lymphocytic Leukemia

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1794-1794 ◽  
Author(s):  
Dongxia Xing ◽  
Alan G. Ramsay ◽  
Simon Robinson ◽  
Catherine M. Bollard ◽  
Nina Shah ◽  
...  
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Nk Cells ◽  
Actin Polymerization ◽  
Synapse Formation ◽  
Immunological Synapse ◽  
Nk Cell ◽  
Immune Dysfunction ◽  
Lymphocytic Leukemia ◽  
Immune Synapse

Abstract Abstract 1794 Immune dysfunction is a hallmark of chronic lymphocytic leukemia (CLL) including suppressed humoral and cell-mediated immune responses. The immunomodulatory agent lenalidomide has shown effective clinical activity against CLL, but its mechanism of action is poorly understood. Previous work has demonstrated that the T cell immunological synapse and functional defects in CLL can be reversed following lenalidomide treatment (J Clin Invest. 2008; 118). Polymerization of F-actin at the NK cell immunological synapse with tumor cells is required for signaling molecules to assemble and regulate NK cell activation and effector function. Confocal microscopy was used to visualize and analyze F-actin polymerization at the immune synapse between NK cells and CLL cells. The impaired immune synapse defect identified in CLL could result from not only the defects of CLL B cells but also defects in the CLL NK cells or a combination of both factors. To investigate the contribution of each factor, we examined synapse formation in experiments using CLL B cells with autologous CLL NK cells or healthy allogeneic NK cells. Conjugates formed with healthy NK cells and CLL B cells exhibited a strong band of F-actin at the immune synapse. In contrast, significantly less actin polymerization at the synapse was observed in autologous CLL NK cells and CLL B cells (P < 0.01). These results indicate CLL B cells, together with CLL NK cells contributed to the immune dysfunction in CLL. As autologous NK cell function in CLL is suppressed, we investigated the utility of CB as a potential functional source of NK cells for CLL immunotherapy. We examined the effect of lenalidomide on NK cell immune synapse function with CLL B cells acting as APCs. We demonstrated that ex vivo treatment of CLL cells with lenalidomide (500 ng/ml) for 48 hours caused a significant increase in the ability of autologous CLL NK cells to form F-actin immune synapses with CLL B cells. The same treatment of CLL B cells also significantly increased the ability of CB-NK cells to form F-actin immunological synapses with these treated CLL B cells compared to untreated CLL B cells (33.6% to 67.3%, P < 0.01, n=6). Our results also show that lenalidomide treatment of autologous NK cells from CLL patients enhanced synapse formation with treated CLL cells compared to experiments using untreated NK cells, but with reduced function compared to CB NK cells. Of note, lenalidomide treatment was shown to increase the recruitment of the signaling molecule Lck to NK cell:CLL cell synapse site, that is known to regulate lytic synapse function. Importantly, lenalidomide treatment significantly increased CB-NK killing of CLL B cells compared to untreated CLL B cells (20.5% versus 48.2%, E:T ratio of 10:1, n = 6, p < 0.001). These results provide insight into the potential mechanism of action of lenalidomide's anti-leukemic function – priming CLL tumor cells for enhanced NK cell lytic synapse formation and effector function. In addition, the data suggests that immunotherapeutic strategies utilizing a combination of CB-NK cells and lenalidomide has an enhanced clinical efficacy in CLL. Disclosures: Gribben: Roche: Honoraria; Celgene: Honoraria; GSK: Honoraria; Mundipharma: Honoraria; Gilead: Honoraria; Pharmacyclics: Honoraria.

scholarly journals Patients with a deficiency of natural killer cell activity lack the VEP13-positive lymphocyte subpopulation

Blood ◽  
1985 ◽  
Vol 65 (1) ◽  
pp. 65-70 ◽  
Author(s):  
HW Ziegler-Heitbrock ◽  
H Rumpold ◽  
D Kraft ◽  
C Wagenpfeil ◽  
R Munker ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Natural Killer Cell Activity ◽  
Killer Cell ◽  
Cell Activity ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Target Cells ◽  
Nk Cell Activity

Abstract Many patients with B-type chronic lymphocytic leukemia (CLL) exhibit a profound defect in their natural killer (NK) cell activity, the basis of which is still obscure. Hence, we analyzed the NK cells from peripheral blood samples from 11 patients with CLL for phenotype and function, after removal of the leukemic cells with a monoclonal antibody (BA-1) plus complement. Phenotypic analysis of these nonleukemic cells with monoclonal antibodies (MoAbs) against NK cells revealed that the CLL patients had higher percentages of HNK-1-positive cells (23.5% compared to controls with 14.7%). In contrast, VEP13- positive cells were absent or low in seven patients (0.8% compared to controls with 11.2%) and normal in four patients (10.5%). When testing NK cell activities against K562 or MOLT 4 target cells, patients with no or minimal numbers of VEP13-positive cells were found to be deficient, while patients with normal percentages of VEP13-positive cells had NK cell activity comparable to controls. Isolation by fluorescence-activated cell sorter of HNK-1-positive cells from patients lacking VEP13-positive cells and NK cell activity indicated that the majority of the HNK-1-positive cells in these patients had the large granular lymphocyte morphology that is characteristic of NK cells. Thus, the deficiency of NK cell activity in CLL patients appears to result from the absence of cells carrying the VEP13 marker.

scholarly journals Association of Natural Killer Cell Dysfunction and Recurrent Stevens-Johnson Syndrome in a Pediatric Patient

2013 ◽  
Vol 4 (1) ◽  
pp. ar.2013.4.0044 ◽  
Author(s):  
Jason Casselman ◽  
John Venglarcik ◽  
Matt Bludorn ◽  
Leah Chernin ◽  
David Swender ◽  
...  
Keyword(s):  
Immune System ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Cell Surface Expression ◽  
Stevens Johnson Syndrome ◽  
Target Cells ◽  
Vaginal Mucosa ◽  
Cell Dysfunction ◽  
Johnson Syndrome

Stevens-Johnson syndrome (SJS) is a debilitating condition involving the skin and mucous membranes. It is commonly the result of adverse drug reactions but can also be caused by infections. A predisposition to recurrent viral infections, such as in the case of natural killer (NK) cell dysfunction, may manifest with virally induced SJS. We present this case to suggest a possible association between NK cell dysfunction and recurrent SJS. An 11-year-old girl presents with recurring erythema, erosion, and ulceration of oral and vaginal mucosa. Small fluid-filled bumps would appear, leading to blistering and later sloughing of mucosal tissue, and bleeding would ensue. Seven separate episodes have occurred over an 8-year period, with each episode being preceded by symptoms of an upper respiratory infection. NK cell function assays were performed and NK cell phenotyping was ordered. NK cell assays showed decreased NK cell cytotoxicity at all ratios of K562 target cells. NK cell surface expression evaluation showed an immature phenotype but normal overall numbers of NK cells. NK cells are a pivotal part of the innate immune system, and, among other things, provide defense of viral infection. This case represents the manifestation of recurrent SJS as a result the lack of protection from viral illness, usually provided by NK cells in the healthy immune system.

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