scholarly journals 894 The bispecific innate cell engagers AFM13 (CD30/CD16A) and AFM24 (EGFR/CD16A) increase the fraction of tumor target-responsive NK cells and boost serial killing

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A938-A938
Author(s):  
Chiara Zambarda ◽  
Karolin Guldevall ◽  
Chiara Zambarda ◽  
Karolin Guldevall ◽  
Christian Breunig ◽  
...  
Keyword(s):  
Nk Cells ◽  
Single Cell ◽  
Tumor Cells ◽  
Cell Biology ◽  
Nk Cell ◽  
Biological Evaluation ◽  
Target Cells ◽  
List Type ◽  
Tumor Target ◽  
Serial Killing

BackgroundThe use of bispecific natural killer (NK) cell engagers has emerged as a successful strategy for immune cell activation and killing of tumor cells through antibody-dependent cellular cytotoxicity (ADCC). Among these, tetravalent, bispecific innate cell engagers (ICE®) with specificity for the activating receptor CD16A selectively triggering innate responses from NK cells or macrophages represent the most clinically advanced concept. The CD30/CD16A specific ICE® AFM13, has shown efficacy in patients with CD30+ lymphomas as monotherapy1 and combination therapy with check-point inhibitors2 and most recently in combination with adoptive NK cell therapy.3 The EGFR/CD16A specific ICE® AFM24, targeting a variety of solid tumors like colorectal, or lung cancer with a unique mode of action independent of EGFR signaling inhibition, is currently evaluated in an ongoing Ph1/2a clinical study.MethodsWe used a microchip-based screening with single cell resolution4 to elucidate the dynamic responses of individual NK cells towards tumor target cells upon treatment with AFM13 or AFM24.ResultsWe found that AFM13 and AFM24 mediated potent activation of NK cells, leading to increased responsive cytotoxic NK cells and significantly increased the number of NK cells that exerted engagement with multiple target cells rendering these NK cells serial killers. Strikingly, bispecific ICE® molecules triggered stronger cytotoxic responses compared to monoclonal antibodies. One suggested strategy to boost killing by NK cells is to use molecular inhibitors or protein constructs that prevent shedding of CD16.5 However, previous results have shown that this can lead to impaired detachment from target cells, reducing the capacity for an individual NK cell to form serial contacts to target cells.6 We observed that the elevated NK cell killing induced by ICE® molecules was largely conserved when cells were treated with the shedding inhibitor Batimastat. Analysis of the functional dynamics of NK cells revealed that inhibition of CD16 shedding prevented NK cell detachment from target cells, resulting in cell cluster formation. This might strongly impact targeting of distant tumor cells by an individual NK cell thus limiting its anti-tumoral activity.ConclusionsIn conclusion, we show that both AFM13 and AFM24 increase the fraction of tumor-target responsive NK cells and boost serial killing of target cells by individual NK cells. Based on these data, ICE® molecules can be characterized as potent anti-tumoral agents leveraging the enormous potential of NK cells while maintaining crucial features of NK cell biology.AcknowledgementsWe thank members of the Önfelt lab for their valuable help and feedback.ReferencesSawas A, Elgedawe H, Vlad G, Lipschitz M, Chen P-H, Rodig SJ, et al. Clinical and biological evaluation of the novel CD30/CD16A tetravalent bispecific antibody (AFM13) in relapsed or refractory CD30-positive lymphoma with cutaneous presentation: a biomarker phase Ib/IIa study (NCT03192202). Blood 2018;132(Supplement 1):2908–2908.Bartlett NL, Herrera AF, Domingo-Domenech E, Mehta A, Forero-Torres A, Garcia-Sanz R, et al. A phase 1b study of AFM13 in combination with pembrolizumab in patients with relapsed or refractory Hodgkin lymphoma. Blood 2020. Blood 2020;136(21):2401–2409.Kerbauy LN, Marin ND, Kaplan M, Banerjee PP, Berrien-Elliott MM, Becker-Hapak M, et al. Combining AFM13, a bispecific CD30/CD16 antibody, with cytokine-activated blood and cord blood–derived NK cells facilitates CAR-like responses against CD30 + malignancies. Clin Cancer Res Epub 2021.Guldevall K, Brandt L, Forslund E, Olofsson K, Frisk TW, Olofsson PE, et al. Microchip screening platform for single cell assessment of NK cell cytotoxicity. Front Immunol 2016;7:119.Romee R, Foley B, Lenvik T, Wang Y, Zhang B, Ankarlo D, et al. NK cell CD16 surface expression and function is regulated by a disintegrin and metalloprotease-17 (ADAM17). Blood 2013;121(18):3599–608.Srpan K, Ambrose A, Karampatzakis A, Saeed M, Cartwright ANR, Guldevall K, et al. Shedding of CD16 disassembles the NK cell immune synapse and boosts serial engagement of target cells. J Cell Biol 2018;217(9):3267–83.Ethics ApprovalThis work was performed with NK cells from healthy anonymous blood donors, which requires no ethical permit according to local regulations.

scholarly journals Deciphering the Immunological Phenomenon of Adaptive Natural Killer (NK) Cells and Cytomegalovirus (CMV)

2020 ◽  
Vol 21 (22) ◽  
pp. 8864
Author(s):  
Samantha Barnes ◽  
Ophelia Schilizzi ◽  
Katherine M. Audsley ◽  
Hannah V. Newnes ◽  
Bree Foley
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Cell Biology ◽  
Nk Cell ◽  
Cell Receptor ◽  
Vital Role ◽  
Immune Memory ◽  
Target Cells ◽  
Cytokines And Chemokines ◽  
Adaptive Immune Cells

Natural killer (NK) cells play a significant and vital role in the first line of defense against infection through their ability to target cells without prior sensitization. They also contribute significantly to the activation and recruitment of both innate and adaptive immune cells through the production of a range of cytokines and chemokines. In the context of cytomegalovirus (CMV) infection, NK cells and CMV have co-evolved side by side to employ several mechanisms to evade one another. However, during this co-evolution the discovery of a subset of long-lived NK cells with enhanced effector potential, increased antibody-dependent responses and the potential to mediate immune memory has revolutionized the field of NK cell biology. The ability of a virus to imprint on the NK cell receptor repertoire resulting in the expansion of diverse, highly functional NK cells to this day remains a significant immunological phenomenon that only occurs in the context of CMV. Here we review our current understanding of the development of these NK cells, commonly referred to as adaptive NK cells and their current role in transplantation, infection, vaccination and cancer immunotherapy to decipher the complex role of CMV in dictating NK cell functional fate.

Preclinical Development of Edit-201, a Multigene Edited Healthy Donor NK Cell with Enhanced Anti-Tumor Function and Superior Serial Killing Activity in an Immunosuppressive Environment

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 33-33
Author(s):  
Christopher M Borges ◽  
Kevin Wasko ◽  
Jared M Nasser ◽  
Kelly Donahue ◽  
Amanda Pfautz ◽  
...  
Keyword(s):  
Cell Growth ◽  
Nk Cells ◽  
Target Cell ◽  
Nk Cell ◽  
Hematologic Malignancies ◽  
Target Cells ◽  
Publicly Traded ◽  
Killing Assay ◽  
Serial Killing

Natural killer (NK) cells distinguish tumor from healthy tissue via multiple mechanisms, including recognition of stress ligands and loss of MHC class I expression. For example, KIR mismatching enables allogenic NK cells to respond to MHC positive tumors in a similar manner to MHC negative tumors, making allogeneic NK cell therapy a promising approach for broad oncology indications. Accordingly, allogenic human HD-NK cells, including gene-modified cells, have demonstrated an impressive safety and efficacy profile when administered to patients with advanced hematologic malignancies. However, effector function of allogeneic NK cells can be diminished by the lack of functional persistence, as well as tumor-intrinsic immunosuppressive mechanisms, such as production of TGF-β. To this end, we developed a next-generation allogeneic NK cell therapy using CRISPR-Cas12a gene editing to enhance NK cell function through knockout of the genes CISH and TGFBR2. Both single and simultaneous targeting (DKO) of TGFBR2 and CISH in NK cells using CRISPR-Cas12a produced in/dels at both targets in greater than 80% of NK cells, with greater than 90% of edited NK cells viable at 72 hours post-editing. Importantly, we find that DKO NK cells do not phosphorylate the SMAD2/3 protein downstream of the TGF-b receptor complex and demonstrate increased phosphorylation of pSTAT3 and pSTAT5 upon IL-15 stimulation, consistent with protein level knockout of TGFBR2 and CISH. To determine whether DKO NK cells exhibited superior function relative to control NK cells, we first measured the ability of DKO NK cells to kill Nalm6 cells (adult B cell ALL) relative to unedited control NK cells. We find that in the presence of exogenous TGF-b, DKO NK cells demonstrate improved cytotoxicity against Nalm6 tumor targets by delaying tumor re-growth in comparison to control NK cells. To better characterize the ability of DKO NK cells to kill tumor cells, we developed an in vitro serial killing assay. In this long-duration assay, up to 30 days, control and DKO NK cells (grown in the presence of IL-15) were challenged every 48 hours with a new bolus of Nalm6 tumor targets. Both DKO and unedited NK cells control Nalm6 target cell growth for greater than 18 days (9 additions of new Nalm6 target cells), demonstrating a surprising ability for the same NK cells to serially kill new Nalm6 target cells for a prolonged period of time in vitro. We find that DKO NK cells produce higher levels of IFN-γ and TNF-α relative to control NK cells over the duration of the entire serial killing assay, suggesting that DKO NK cells can continue to produce these inflammatory cytokines even after serial killing. As many tumors, including hematologic malignancies, have high concentrations of TGF-β in their microenvironments, we next tested the ability of DKO NK cells to control the growth of Nalm6 cells in our serial killing assay in the presence of TGF-b. 10ng/mL TGF-β was added at the start of the assay as well as at each addition of new Nalm6 target cells. We observed that control NK cells fail to restrict Nalm6 target cell growth beyond 4 days (after 1 addition of new Nalm6 target cells) whereas DKO NK cells control Nalm6 target cell growth for greater than 18 days (after 9 additions of new Nalm6 target cells). Similar to the serial killing assay without TGF-b, we find that DKO NK cells produce higher concentrations of IFN-γ and TNF-α relative to control NK cells over the duration of the entire serial killing assay. Broadening our repertoire of target cells beyond B cell malignancies is now in progress, including the AML-like cell lines HL-60 and THP-1, the multiple myeloma cell line RPMI 8226, and various solid tumor targets. In summary, using CRISPR-Cas12a we demonstrated highly efficient gene editing of primary human NK cells at two unique targets designed to augment NK cell anti-tumor activity across a variety of malignancies. Most significantly, we demonstrate sustained anti-tumor serial-killing activity in the presence of the potent immunosuppressive cytokine TGF-β. Together, the increased overall effector function of CISH/TGFBR2 DKO primary human NK cells and their ability to serial kill, support their development as a potent allogeneic cell-based medicine for cancer. This potential medicine, termed EDIT-201, is being advanced to clinical study. Disclosures Borges: Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Wasko:Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Nasser:Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Donahue:Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Pfautz:Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Antony:Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Leary:Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Sexton:Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Morgan:Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Wong:Editas Medicine: Current Employment, Current equity holder in publicly-traded company.

IPH2101, a Novel Anti-Inhibitory KIR Monoclonal Antibody, and Lenalidomide Combine to Enhance the Natural Killer (NK) Cell Versus Multiple Myeloma (MM) Effect.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3870-3870 ◽  
Author(s):  
Don Benson ◽  
Courtney E Bakan ◽  
Shuhong Zhang ◽  
Lana Alghothani ◽  
Jing Liang ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Nk Cells ◽  
Tumor Cells ◽  
Nk Cell ◽  
Phase 1 ◽  
Granzyme B ◽  
Cell Activity ◽  
Target Cells ◽  
Nk Cell Activity ◽  
Immune Complex Formation

Abstract Abstract 3870 Poster Board III-806 Background NK cell activity against tumor cells is regulated by a balance of inhibitory and activating signals mediated by receptors on NK cells that recognize inhibitory and activating ligands expressed by cancer cells. IPH2101 (1-7F9) is a novel monoclonal anti-inhibitor KIR blocking antibody that has been shown to augment NK cell function against MM targets. Moreover, lenalidomide has been shown to expand and activate NK cells in vivo and in vitro. We have previously reported that the combination of IPH2101 and lenalidomide enhances NK cell mediated cytotoxicity against MM cells compared to each agent alone (Zhang et al., AACR 2009). We expand our studies to investigate potential mechanisms for the enhancement of NK cell activity by the combination of IPH2101 and lenalidomide. Methods The effects of IPH2101 and lenalidomide alone and in combination were studied using primary human NK cells from healthy donors as well as from MM patients. The MM cell lines U266 and RPMI 8226 as well as primary tumor cells from marrow aspirates of MM patients served as target cells. The effect of lenalidomide on MM activating and inhibitory ligand expression was studied by flow cytometry. NK cell trafficking was investigated with standard transwell plate migration assay. Immune complex formation between NK cell effectors and MM tumor targets was characterized by flow cytometry in control conditions and with NK cells pre-treated with IPH2101 and lenalidomide. The effects of IPH2101 and lenalidomide were studied regarding interferon-gamma and granzyme B production by ELISPOT and target-specific cytotoxicity studies were conducted to complement effector-based assays. Results IPH2101 (30 ug/ml) significantly enhanced cytotoxicity against U266 cells and primary MM tumor cells by both purified NK cells at effector:target (E:T) ratios of 10:1 or less, and also of freshly isolated peripheral blood mononuclear cells (PBMC) at E:T ratios of 60:1 or less, from more than 10 random donors. In addition, treatment of PBMC with 5-10 μmol/L lenalidomide for 72h without interleukin (IL)-2 increased NK cell lysis of U266. Treatment of PBMC from normal donors did not enhance the expression of the NK receptors KIR, NKG2D, NCR, TRAIL, and DNAM-1. Incubation of U266 cells with lenalidomide (5 uM) for 3-5 days resulted in significant enhancement of cytotoxicity by normal donor NK cells. This was associated with upregulation of the activating ligands, MICA, ULBP-2, DR4, and CD112. Using blocking antibodies to NKG2D, TRAIL, and DNAM-1, lenalidomide enhancement of MM cell killing was abrogated indicating the importance of the modulation of the ligands to the latter receptors by lenalidomide. Although IPH2101 and lenalidomide did not significantly increase NK cell migration into normal media, migration was enhanced 2.98-fold (+/− 0.36, p < 0.05) towards U266 cell targets (n= 3, p < 0.05) and MM patient serum 3.2-fold (+/− 0.4, n=3, p < 0.05). IPH2101 and lenalidomide also led to a 2.3-fold (+/− 0.43, p < 0.05) increase in immune complex formation between NK cells and MM tumor cells. IPH2101 and lenalidomide also augmented NK cell interferon gamma production against MM (control mean 303 spots/well +/− 13 versus 525 +/− 83, n=3, p < 0.05) and granzyme B production (control mean 115 +/− 98 versus 449 +/−72, n=3, p < 0.05). Importantly, in all experiments described herein, the effects of IPH2101 and lenalidomide together were greater than either agent alone. Conclusions Taken together, our data suggest that IPH2101 and lenalidomide may exert complementary mechanisms on both effector and target cells to enhance NK cell mediated killing of MM cells. Moreover, these agents have no predicted clinical cross-toxicities. A single-agent phase 1 clinical trial of IPH2101 has shown the mAb to be safe and well tolerated in MM patients. These findings support a phase 1/2 clinical trial of IPH2101 with lenalidomide as a first dual-innate immunotherapy for patients with MM. Disclosures: Andre: Innate Pharma: Employment. Squiban:Innate pharma: Employment. Romagne:Innate Pharma: Employment.

Immune Function in Follicular Lymphoma (FL): Comparison of Patient with Her Healthy Identical Twin Reveals Enhanced NK Cell Responses in the Patient During Spontaneous Remission [KC1].

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 5012-5012
Author(s):  
Elena Gitelson ◽  
Alexander W. MacFarlane ◽  
Kerry S Campbell ◽  
R. Katherine Alpaugh ◽  
Tahseen I. Al-Saleem ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Line ◽  
Peripheral Blood ◽  
Partial Remission ◽  
Nk Cell ◽  
Identical Twin ◽  
Effector Memory ◽  
Target Cells ◽  
Tumor Target ◽  
Memory Phenotype

Abstract Abstract 5012 Identical twins are an excellent model in which to study tumor-specific immune responses (Gitelson et al Br J Haem 2002) as it can be postulated that the immune systems are identical. Spontaneous remissions in FL occur but the immunologic mechanisms remain elusive. We investigated adaptive and innate immunologic phenotypes and responses in a 41-year old patient with untreated grade 1 FL, and her healthy identical twin sister. Patients and methods The patient has had a waxing and waning course of FL over 7 years and currently is in spontaneous partial remission (> 50% reduction of generalized lymphadenopathy) and her peripheral blood was negative for t(14:18) by PCR at the time of this analysis. Immunologic responses of her twin, as well as another set of healthy identical twin sisters, were investigated as controls. We studied peripheral blood using 8-color multiparametric flow cytometry for frequencies and phenotypes of NK and regulatory T cells (Tregs). FOXP3+ cells were further analyzed for naïve, central memory and effector memory phenotype. Activation of NK cells and degranulation in response to tumor target cells as measured by Lysosomal-Associated Membrane Protein 1 (LAMP-1) surface expression were investigated. An erythroblastoid cell line (K562) and an EBV transformed MHC-I deficient lymphoblastoid cell line (721.221) were used as targets. Results NK studies revealed that activated CD69+ NK cells were increased in percentage in FL patient (4.43%) compared to her healthy twin (1.82%), and had increased mean fluorescence intensity (MFI) of 1057 vs 357, respectively. In contrast, almost identical frequencies and MFI of activated NK cells were found in the set of healthy twins (0.55% vs 0.54% and 153 vs 153, respectively). NK cells of FL patient exhibited elevated degranulation compared to the healthy twin in response to stimulation by either target cell: LAMP-1 staining MFI 1907 vs 1395, respectively for 721.221 target cells and 1394 vs 1122, respectively for K562 cells, whereas no difference was detected in non-stimulated NK cells (MFI 536 vs 506, respectively). In addition, Killer Cell Immunoglobulin-like Receptor (KIR) analysis revealed a deficit in the percentage of NK cells staining with an antibody recognizing KIR2DL1/S1 in the patient, but not in her healthy twin (7.0% vs 15.1% of NK cells, respectively), whereas no other differences in KIR receptor expression profiles were found for other KIR or in comparing the set of healthy twins. Analysis of frequencies of circulating Tregs revealed no difference between FL patient and her healthy twin: CD4+CD25+FOXP3+ cells represented 4.92% vs 5.78%, respectively of total CD4 cells and CD8+CD25+FOXP3+ cells represented 1.25% vs 1.37%, respectively of total CD8 cells. Analysis of T cell subsets revealed that Tregs in FL patient and in her twin were mainly of effector memory phenotype: CCR7-/CD45RA-/CD45RO+ (82.6% vs 74.4%, respectively) and central memory phenotype: CCR7+/CD45RA-/CD45RO+ (10.7 vs 14.3%, respectively). Conclusions NK cell studies of FL patient revealed increased numbers of activated CD69+ NK cells which correlated with increased degranulation response to tumor target cells and a deficit in the NK cell repertoire, as noted by the deficiency in NK cells expressing KIR2DL1/S1 in the patient compared to the healthy twin, while no differences in frequencies of circulating Tregs or Treg phenotypes were identified. Although the current results are based upon a single sampling, due to limited availability, the observed potentiation of NK cell activity in the patient with FL suggest a potentially important role of NK cells in tumor control during spontaneous partial remission. Follow-up studies of persisting remission, temporary flare-up or at disease progression will be of interest. Disclosures No relevant conflicts of interest to declare.

Pseudoexpression of Glucocorticoid-Induced TNF-Related (GITR) Ligand Upon Coating of Cancer Cells by Platelets Impairs NK Cell Anti-Tumor Reactivity

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3193-3193 ◽  
Author(s):  
Theresa Placke ◽  
Lothar Kanz ◽  
Helmut R. Salih ◽  
Hans-Georg Kopp
Keyword(s):  
Nk Cells ◽  
Tumor Cells ◽  
Nk Cell ◽  
Conflicts Of Interest ◽  
Immune Surveillance ◽  
Substantial Reduction ◽  
Cell Activity ◽  
Target Cells ◽  
Tumor Immune Escape ◽  
Tumor Spread

Abstract Abstract 3193 NK cells as part of the innate immune system substantially contribute to cancer immune surveillance. They prevent tumor progression and metastasis due to their ability to mediate cellular cytotoxicity and to produce cytokines like IFN-γ, which, among others, stimulates subsequent adaptive immune responses. NK reactivity results from an integrative response emerging upon recognition of multiple ligands for activating and inhibitory NK cell receptors including various members of the TNFR family. Apart from the direct interaction with their target cells, NK cell activity is further influenced by the reciprocal interplay with various other hematopoietic cells like e.g. dendritic cells. Metastatic tumor spread in experimental animals is dramatically reduced in thrombopenic mice. Additional depletion of NK cells reverses this effect, indicating that platelets may impair NK anti-tumor reactivity. However, the underlying mechanisms have not been fully elucidated, especially in humans. Recently, we demonstrated that NK anti-tumor immunity is impaired by platelet-derived TGF-β, which is released upon interaction of platelets with tumor cells (Kopp et al., Cancer Res. 2009). Here we report that the ligand for the TNFR family member GITR (GITRL) is upregulated on megakaryocytes during maturation resulting in substantial GITRL expression by platelets. Since we recently identified GITR as inhibitory NK receptor involved in tumor immune escape (e.g., Baltz et al., Blood 2008, Baessler et al., Cancer Res. 2009) we investigated how platelet-derived GITRL influences platelet function and NK immune surveillance. Signaling via GITRL into platelets upon interaction with NK-expressed GITR or recombinant GITR-Ig fusion protein did not alter platelet activation as revealed by analysis of the activation marker CD62P and release of TGF-β. Interestingly, we found that GITRL-negative tumor cells rapidly get coated by platelets, which confers a seemingly GITRL-positive phenotype. “GITRL pseudoexpression” on tumor cells caused a substantial reduction of NK cell cytotoxicity and cytokine production. This reduced NK reactivity was not due to induction of apoptosis via GITR and could be restored by addition of a blocking GITR antibody. Thus, coating of tumor cells by platelets inhibits NK reactivity, which is in part mediated by platelet-derived GITRL. Our data provide a functional basis for the previously observed finding that platelets increase metastasis i.e. by enabling evasion of tumor cells from NK-mediated immune surveillance. Disclosures: No relevant conflicts of interest to declare.

Transfer of MHC Class I by Coating Platelets Enables Tumor Cells to Evade NK Cell Immune Surveillance by Conferring a “Pseudo Self” Phenotype

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 583-583 ◽  
Author(s):  
Theresa Placke ◽  
Hans-Georg Kopp ◽  
Martin Schaller ◽  
Gundram Jung ◽  
Lothar Kanz ◽  
...  
Keyword(s):  
T Cell ◽  
Nk Cells ◽  
Tumor Cells ◽  
Mhc Class I ◽  
Nk Cell ◽  
Immune Surveillance ◽  
Class I ◽  
Immunofluorescent Staining ◽  
Target Cells ◽  
Missing Self

Abstract Abstract 583 NK cells are a central component of the cytotoxic lymphocyte compartment capable of lysing tumor cells without prior immune sensitization of the host. The mechanisms leading to activation of NK reactivity are described by the principles of ‘missing-self' and ‘induced-self', which imply that cells with a low or absent expression of MHC class I (‘missing-self') and/or a stress-induced expression of ligands of activating NK receptors like e.g. NKG2D (‘induced-self') are preferentially recognized and eliminated by NK cells. Thus, a balance of various activating and inhibitory signals determines whether NK cell responses are initiated or not. Tumor cells often downregulate expression of MHC class I to evade T cell-mediated immune surveillance, which results in enhanced NK susceptibility. Besides the direct interaction with their target cells, NK activity is further influenced by the reciprocal interplay with various other hematopoietic cells. We and others demonstrated previously that thrombocytopenia inhibits metastasis in murine models, which is reversed by additional depletion of NK cells (e.g., Jin et al., Nature Med. 2006, Palumbo et al., Blood 2005). However, the mechanisms by which platelets impair NK-tumor interaction are largely unclear, especially in humans. Recently we reported that platelets release TGF-β upon interaction with tumor cells causing downregulation of NKG2D on NK cells, which impairs anti-tumor immunity by disturbing the principle of “induced self” (Kopp et al., Cancer Res. 2009). Here we demonstrate that platelets further enable tumor cells to evade NK cell immune surveillance by preventing detection of “missing self”: We found that tumor cells rapidly get coated in the presence of platelets, the latter expressing large amounts of MHC class I on their surface. In case of MHC class I-negative or -low cancer cells, this process results in MHC class I “pseudoexpression” on the tumor cell surface as revealed by flow cytometry, immunofluorescent staining, and electron microscopy. Platelet-derived MHC class I was found to inhibit the reactivity of autologous NK, both upon activation with cytokines and, most importantly, in cultures with platelet-coated tumor cells. Using constitutively MHC class I-negative/low tumor cells we found that blocking MHC class I restored NK cytotoxicity and IFN-γ production against platelet-coated tumor cells, but did not alter NK reactivity against the tumor cells in the absence of coating platelets. Taken together, our data indicate that platelets enable a molecular mimicry of tumor cells, allowing the latter to downregulate MHC class I in order to escape T cell immunity without inducing sufficient NK tumor immune surveillance due to conferred platelet-mediated “pseudo self”. Disclosures: No relevant conflicts of interest to declare.

scholarly journals NK cells switch from granzyme B to death receptor–mediated cytotoxicity during serial killing

2019 ◽  
Vol 216 (9) ◽  
pp. 2113-2127 ◽  
Author(s):  
Isabel Prager ◽  
Clarissa Liesche ◽  
Hanna van Ooijen ◽  
Doris Urlaub ◽  
Quentin Verron ◽  
...  
Keyword(s):  
Cell Death ◽  
Nk Cells ◽  
Tumor Cells ◽  
Nk Cell ◽  
Granzyme B ◽  
Death Receptor ◽  
Death Receptors ◽  
Cell Contact ◽  
Cell Death Pathways ◽  
Serial Killing

NK cells eliminate virus-infected and tumor cells by releasing cytotoxic granules containing granzyme B (GrzB) or by engaging death receptors that initiate caspase cascades. The orchestrated interplay between both cell death pathways remains poorly defined. Here we simultaneously measure the activities of GrzB and caspase-8 in tumor cells upon contact with human NK cells. We observed that NK cells switch from inducing a fast GrzB-mediated cell death in their first killing events to a slow death receptor–mediated killing during subsequent tumor cell encounters. Target cell contact reduced intracellular GrzB and perforin and increased surface-CD95L in NK cells over time, showing how the switch in cytotoxicity pathways is controlled. Without perforin, NK cells were unable to perform GrzB-mediated serial killing and only killed once via death receptors. In contrast, the absence of CD95 on tumor targets did not impair GrzB-mediated serial killing. This demonstrates that GrzB and death receptor–mediated cytotoxicity are differentially regulated during NK cell serial killing.

scholarly journals 881 Enhanced antibody-mediated phagocytosis and antibody-mediated cell cytotoxicity using tetravalent, bispecific innate cell engagers (ICE®) in 3D spheroids

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A923-A923
Author(s):  
Sheena Pinto ◽  
Savannah Jackson ◽  
Julia Knoch ◽  
Christian Breunig ◽  
Arndt Schottelius ◽  
...  
Keyword(s):  
Nk Cells ◽  
Tumor Cells ◽  
Nk Cell ◽  
Target Cells ◽  
Innate Immune Responses ◽  
Patient Derived Xenograft ◽  
Programmed Death ◽  
Preclinical And Clinical Studies ◽  
Donor Pbmcs

BackgroundThe redirected optimized cell platform (ROCK®) enables the generation of customizable innate cell engagers (ICE®) of varying valency, affinity, and pharmacokinetic profiles. Preclinical and clinical studies have demonstrated the advantage and unique features of this first-in-class ICE® antibodies across a multitude of cancers and its differentiation to monoclonal antibodies. ICE® are tetravalent, bispecific antibodies that bivalently bind to a unique epitope on CD16A, which is selectively expressed on natural killer (NK) cells and macrophages, while the other domains target a tumor antigen. In addition to promoting antibody-dependent cellular cytotoxicity (ADCC) of NK cells, ICE® can also promote tumor targeting of macrophages eventually inducing antibody-dependent cellular phagocytosis (ADCP).MethodsADCP and ADCC assays were performed using monocyte-differentiated macrophages and NK cells derived from healthy donor PBMCs. Target tumor lines and patient-derived xenograft line-derived spheroids were labelled and co-cultured with macrophages or NK cells. Live-cell imaging (IncuCyte®) was used to measure ADCP and ADCC events.ResultsWe show that ICE® molecules can enhance ADCP of tumor cells mediated by various functional/phenotypic subsets of macrophages derived from in vitro differentiation of human monocytes. ICE®-induced ADCP of tumor target cells was seen across different macrophage subtypes (M1 and M2). We further investigated the expression of immune-suppressive checkpoint programmed death-ligand 1 (PD-L1) on macrophages upon ICE® treatment that could be a key anti-tumor molecule within the suppressive tumor microenvironment. Based on patient-derived xenograft line-derived spheroids (3D) generated from primary tumor samples of patients suffering from various malignancies, we could demonstrate robust ADCC and ADCP mediated by NK cells and macrophages, respectively.ConclusionsICE® molecules are able to mount robust NK cell- and macrophage-mediated anti-tumoral innate immune responses. This combined immune activity has the potential to not only fight tumor cells directly but also to initiate a full immune response comprised of innate and adaptive components of the immune system.

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

2018 ◽  
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.

Artificial Antigen Presenting Cells (aAPC) Expanded NK-Mediated Enhanced Lysis of Allogeneic Tumor Cells Regardless of HLA Class I/KIR Mismatch and Its Implication of Use in Eradicating Acute Lymphoblastic Leukemia (ALL).

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3023-3023
Author(s):  
Hua Zhang ◽  
Bruce Levine ◽  
Nga Voong ◽  
Alan S. Wayne ◽  
Carl H. June ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Nk Cells ◽  
Natural Killer ◽  
Solid Tumors ◽  
Tumor Cells ◽  
Fusion Proteins ◽  
Nk Cell ◽  
Lymphoblastic Leukemia ◽  
Target Cells ◽  
Activating Receptors

Abstract Abstract 3023 Poster Board II-999 NK Killer cell immunoglobulin-like receptors (KIRs) and their human leukocyte antigen (HLA) ligands play critical roles in maintaining natural killer (NK) cell tolerance, while providing surveillance against pathogens and malignant transformation. Natural killer (NK) cells have been explored as tools for adoptive anti-tumor or leukemia immunotherapy and current models hold that a mismatch or absence of KIR ligands on target cells is essential for efficient NK cell mediated cytolysis. However, new approaches are now available to activate NK cells and the role for KIR mediated signaling in regulating cytotoxicity of activated NK cells has not been well studied. In this study, aAPCs comprising IL15Ra+K562 cells engineered to express 4-1BBL activated and expanded peripheral NK cells in the presence of exogenous IL15 up to 1000-fold in 3 weeks. Compared to resting NK cells, 4-1BBL/IL15-activated NK cells upregulated TRAIL and NKp30, 44, 46 expression, and showed significantly enhanced cytotoxicity against a multitude of tumor targets including K562, Daudi, Ewing's tumors, osteosarcoma, as well as autologous tumors (50%-90% killing vs. 0%-8% with non-activated NK cells). Meanwhile we could detect little to no influence of KIR signaling in regulating cytotoxicity by aAPC activated NK cells, since sorted CD158a+ and CD158b+ activated NK cells showed similar killing of tumor cells expressing HLA group C1 (CD158b ligand) and/or C2 (CD158a ligand) antigens. In contrast, killer activating receptors (KARs) were indispensable for the cytolysis of solid pediatric tumors by aAPC-activated NK cells, since the killing was significantly inhibited by fusion proteins binding to the ligands of NKG2D, NK p30, p44, p46, p80 (KARs). About 20-40% inhibition of the killing was accomplished when all four activating receptors were blocked, though other activating receptors have not been well defined. Although acute lymphoblastic leukemia (ALL) blasts were refractory to fresh NK cytotoxicity, 4-1BBL/IL15 activated NK cells demonstrated higher lytic activities (20%-50%) against ALL blasts from either patients or cell lines. ALL blast lysis could be completely or partially inhibited by KAR-blocking fusion proteins, indicating that expression levels of KAR ligands vary among ALL cases and other solid tumors. We conclude that KIR ligand mismatch or absence is not essential for effective NK cytotoxicities on either solid tumors or ALL when fully activated NK cells are utilized. This suggests that adoptive therapy with autologous aAPC-activated NK cells may prove effective in some clinical settings, such as ALL, AML, or certain solid tumors. Further studies to assess the impact of KAR ligand expression on aAPC-activated NK killing of ALL blasts are in progress. Percentage of Activated NK Killings vs. Fresh NK's with/without KAR-Ig Fusion Proteins Activated NK (E:T=2.5:1) Fresh NK (E:T=25:1) -KAR-Ig Fc +KAR-Ig Fc SB tumor (Ewing's) 48% 30% 0.5% HOS (Osteo sarcoma) 63% 36% 0.7% Daudi (B. lymphoma) 78% 46% 0.2% REH (ALL) 54% 8% 3% Disclosures No relevant conflicts of interest to declare.

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