scholarly journals Memory-Like Natural Killer Cells

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. SCI-8-SCI-8 ◽  
Author(s):  
Melissa M Berrien-Elliott ◽  
Julia A Wagner ◽  
Amanda F Cashen ◽  
Todd A Fehniger

Abstract Natural killer (NK) cells, classically considered to be part of the innate immune system, are specialized for rapid responses that protect the host against pathogens and eliminate malignant cells. These functional responses are multi-faceted, and include not only direct target cell killing, but also production of cytokines and chemokines, proliferative expansion, and cross-talk with various immune cells to help orchestrate cellular immunity. NK cell recognition of a target cell is controlled by the integration of signals from germline-DNA encoded activating, inhibitory, and cytokine receptors. NK cell tolerance toward healthy host cells arises via education or licensing that requires self-inhibitory receptor engagement. Over the past decade, it has become clear that NK cells have the capacity to remember prior activation events, including hapten-exposure,1 viral infection,2 and combined cytokine stimulation.3 These studies have defined "memory", "adaptive", and "memory-like" responses by NK cells within both murine and human immune systems, which can result in long-lived NK cell populations with enhanced effector functionality.4-6 While certain types of NK cell "memory" can be specific to the original stimulation, other types of "memory-like" responses are non-specific, providing flexibility in the enhanced response to subsequent activating triggers.7 Cytokine-induced memory-like NK cells were originally discovered in mice, following a brief exposure to the potent activating combination of IL-12, IL-15 and IL-18.3 After this activation, murine memory-like NK cells differentiated in vivo, and demonstrated enhanced IFN-γ recall responses to IL-12 and IL-15 re-stimulation, even after extensive cell division. Subsequent studies identified human IL-12/15/18-induced memory-like NK cells that displayed enhanced function after re-stimulation via cytokine receptors, activating receptors, or tumor targets.8 Adoptive transfer of murine memory-like NK cells into syngeneic or immunodeficient mice resulted in an enhanced ability to control lymphomas and solid tumors in vivo,9 as well as the ability to persist in the recipient for months. In addition, memory-like NK cell differentiation restored the anti-tumor function of unlicensed NK cells, demonstrating that cytokine receptor signals can overcome a lack of NK cell education.10 Other studies showed that memory-like NK cells can ignore inhibitory receptor signals, and have enhanced anti-leukemia responses.11 Based on these pre-clinical findings, we translated allogeneic memory-like NK cells into the clinic in a first-in-human adoptive cell therapy trial for patients with relapsed/refractory (rel/ref) myeloid malignancies. This study demonstrated that rel/ref AML patients were able to safely receive IL-12/15/18-activated donor NK cells (up to 10x106/kg) without developing cytokine release syndrome, neurotoxicity, or graft-versus-host disease. Immune monitoring revealed that memory-like NK cells expanded, trafficked to the bone marrow, and exhibited enhanced anti-leukemia function ex vivo. Clinical responses (CR/CRi) were observed in >50% of patients with active rel/ref AML.11 Ongoing studies are exploring memory-like NK cell adoptive immunotherapy in a phase 2 trial for rel/ref AML, combined with same-donor allogeneic hematopoietic cell transplantation (HCT), and for relapse after allogeneic HCT. Active areas of investigation in memory-like NK cell biology and therapeutics include defining mechanisms that regulate memory-like differentiation and enhanced function, elucidating memory-like NK cell checkpoints, evaluating autologous memory-like NK cell responses against cancers, and developing strategies to enhance memory-like NK cell targeting of resistant malignancies. O'Leary JG, Goodarzi M, Drayton DL, Yu H, von Andrian UH. T cell- and B cell-independent adaptive immunity mediated by natural killer cells. Nat Immunol. 2006;7(5):507-16. Sun JC, Beilke JN, Lanier LL. Adaptive immune features of natural killer cells. Nature. 2009;457(7229):557-61. Cooper MA, Elliott JM, Keyel PA, et al. Cytokine-induced memory-like natural killer cells. Proc Natl Acad Sci USA. 2009;106(6):1915-9. Rölle A, Pollmann J, Cerwenka A. Memory of Infections: An Emerging Role for Natural Killer Cells. PLoS Pathog. 2013;9(9):1-3. Schlums H, Cichocki F, Tesi B, et al. Cytomegalovirus Infection Drives Adaptive Epigenetic Diversification of NK Cells with Altered Signaling and Effector Function. Immunity. 2015;42(3):443-456. Lee J, Zhang T, Hwang I, et al. Epigenetic Modification and Antibody-Dependent Expansion of Memory-like NK Cells in Human Cytomegalovirus-Infected Individuals. Immunity. 2015;42(3):431-442. Fehniger TA, Cooper MA. Harnessing NK Cell Memory for Cancer Immunotherapy. Trends Immunol. 2016;Epub Oct 2:10.1016/j.it.2016.09.005. Romee R, Schneider SE, Leong JW, et al. Cytokine activation induces human memory-like NK cells. Blood. 2012;120(24):4751-4760. Ni J, Miller M, Stojanovic A, Garbi N, Cerwenka A. Sustained effector function of IL-12/15/18-preactivated NK cells against established tumors. J Exp Med. 2012;209(13):2351-2365. Wagner JA, Berrien-Elliott MM, Rosario M, et al. Cytokine-Induced Memory-Like Differentiation Enhances Unlicensed NK Cell Anti-Leukemia and FcγRIIIa-Triggered Responses. Biol. Blood Marrow Transplant. 2016;dx.doi.org: Romee R, Rosario M, Berrien-Elliott MM, et al. Cytokine-induced memory-like natural killer cells exhibit enhanced responses against myeloid leukemia. Sci. Transl. Med. 2016;8(357):357:doi: 10.1126/scitranslmed.aaf2341. Figure. Figure. Disclosures Fehniger: Altor BioScience: Research Funding; Cyto-Sen Therapeutics: Consultancy; Celgene: Research Funding; NIH/NCI: Other: R01 CA205239, P50CA171963; Affimed: Research Funding.

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2918-2918
Author(s):  
Tarun K. Garg ◽  
Junaid Khan ◽  
Susann Szmania ◽  
Amy D Greenway ◽  
Joshuah D Lingo ◽  
...  

Abstract Abstract 2918 Natural killer cells (NK) have the unique ability to kill target cells without priming. While their therapeutic potential against various malignancies is becoming more apparent, it has been restricted to the allogeneic setting; NK cells are inhibited by autologous targets by engaging killer immunoglobulin-like receptors with their ligands. Another major challenge to the clinical utility of NK cells is obtaining a sufficient number of NK cells for infusion. Co-culture of blood mononuclear cells (PBMNC) with the leukemic cell line K562, genetically modified to express membrane-bound IL15 and the co-stimulatory molecule 41BBL (K562mbIL15-41BBL) in the presence of IL2 results in robust expansion and activation of NK cells. To determine if NK cells derived from myeloma (MM) patients can be used therapeutically in the autologous setting, we explored the expansion of NK cells from MM patients, their gene expression profiles (GEP), and their ability to kill autologous and allogeneic MM cells from high-risk patients in vitro and in vivo, and compared these to NK cells from healthy donors (HD). PBMNC from MM patients (N=30) co-cultured with irradiated K562mbIL15-41BBL cells expanded a median of 351 fold (range20–10, 430), comparable to the expansion of HD-derived NK cells (N=15, median 803, range 127–1, 727; p=0.5). GEP of MM non-exp-NK differed from HD non-exp-NK in the expression of only one gene (PRKCi), underexpessed in MM (false discovery rate (FDR) <0.05, p-value <3×10−10). GEP of exp-NK cells from both MM patients and HD was very different from non-exp-NK cells (8 pairs each, 10, 639 differentially overexpressed and 26, 057 underexpressed probe sets, FDR <0.05). Genes associated with proliferation, cytolytic activity, activation, adhesion, migration and cell cycle regulation were highly up-regulated in exp-NK cells. Standard chromium release assays demonstrated that MM exp-NK cells killed both allogeneic and autologous primary MM cells more efficiently compared to non-exp-NK cells, via a perforin mediated mechanism. Blocking studies revealed that the natural cytotoxicity receptors, activating receptors, and DNAX accessory molecule (DNAM-1) played a central role in target cell lysis. The killing ability of MM patient and HD derived exp-NK cells was very similar against allogeneic targets, while primary MM targets were more resistant to killing by autologous exp-NK. The anti-MM activity of allogeneic and autologous exp-NK cells was further examined in vivo. NOD/SCID/IL2R γ-null mice were implanted subcutaneously with a human fetal bone, and primary MM cells or luciferase-transfected OPM2 MM cell line were engrafted into the bone. The tumor burden was determined by ELISA for human Ig and/or bio-imaging. The mice were randomized to control and exp-NK treatment groups. A total of 160 ×106 exp-NK cells, in 4 doses 48 hrs apart, were injected in the exp-NK treatment group via tail vein injection. The mice were administered 1000U of IL2 subcu daily to support the NK cells. The mice were bled on days 7, 14, 21 & 28 for the assessment of human Ig by ELISA and enumerating circulating NK cells by flow cytometry. Exp-NK treated mice had a significantly reduced MM burden by ELISA (p<0.04) on day 21, and exp-NK could be detected in the murine blood up to day 28 post-administration in both primary MM and OPM2 tumor bearing mice. The mice were sacrificed and the tumors were harvested after 4 weeks. A noticeable reduction in tumor burden in the exp-NK cell treated mice was confirmed by histology. NK cells were detected by immunohistochemistry (CD57 or CD16) in the hu-bone implants harvested 28 days after infusion. In conclusion, MM patient-derived NK cells have a similar expansion potential, and MM exp-NK cells have cytolytic activity against allogeneic targets similar to those of HD exp-NK cells, and somewhat reduced activity against autologous targets. These exp-NK cells have significant activity against the aggressive cell line OPM2 and high-risk autologous primary MM cells in vivo. Exp-NK cells trafficked to MM tumors and persisted in the myelomatous hu bone microenvironment for 4 weeks. The anti-MM activity of autologous exp-NK cells is exciting and avails a new therapeutic avenue for patients with GEP-defined high-risk disease. A phase II clinical trial of allogeneic and autologous exp-NK cell therapy for relapsed/refractory high-risk MM is in progress at our institution. Disclosures: No relevant conflicts of interest to declare.


2016 ◽  
Vol 213 (11) ◽  
pp. 2249-2257 ◽  
Author(s):  
Luhua H. Zhang ◽  
June Ho Shin ◽  
Mikel D. Haggadone ◽  
John B. Sunwoo

A tissue-resident population of natural killer cells (NK cells) in the liver has recently been described to have the unique capacity to confer immunological memory in the form of hapten-specific contact hypersensitivity independent of T and B cells. Factors regulating the development and maintenance of these liver-resident NK cells are poorly understood. The aryl hydrocarbon receptor (AhR) is a transcription factor modulated by exogenous and endogenous ligands that is important in the homeostasis of immune cells at barrier sites, such as the skin and gut. In this study, we show that liver-resident NK (NK1.1+CD3−) cells, defined as CD49a+TRAIL+CXCR6+DX5− cells in the mouse liver, constitutively express AhR. In AhR−/− mice, there is a significant reduction in the proportion and absolute number of these cells, which results from a cell-intrinsic dependence on AhR. This deficiency in liver-resident NK cells appears to be the result of higher turnover and increased susceptibility to cytokine-induced cell death. Finally, we show that this deficiency has functional implications in vivo. Upon hapten exposure, AhR−/− mice are not able to mount an NK cell memory response to hapten rechallenge. Together, these data demonstrate the requirement of AhR for the maintenance of CD49a+TRAIL+CXCR6+DX5− liver-resident NK cells and their hapten memory function.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A137-A137
Author(s):  
Hadia Lemar ◽  
Anmol Vohra ◽  
Ming-Hong Xie ◽  
Ivan Chan ◽  
Sasha Lazetic ◽  
...  

BackgroundNK cells expanded on membrane-bound (mb) IL-15 and 41BBL expressing K562 stimulatory cells (NKSTIM) for clinical use can be genetically modified to express activating chimeric receptors.1 2 3 NK cells activated in the presence of IL-12, IL-15 and IL-18 develop cytokine induced memory-like (CIML) phenotype and function; these cells have shown clinical promise.4 Additionally, HSCT AML transplants using NK KIR Haplotype Group B donors with better and best Group B profiles (≥2 activating genes) show better survival.5 6 Here we investigate whether KIR profiles impact healthy allogeneic donor NK cell function and phenotype when these cells are expanded on NKSTIM in the presence of IL-12 and IL-18 (12–18).MethodsHealthy donor PBMC NK were genotyped for HLA and KIR and expanded on K562-mbIL15-41BBL stimulatory cells with IL-2 alone or with IL-2 plus IL-12 and IL-18 (12–18). Expanded NK were transduced with CAR constructs including CD19, and then evaluated for NK cell expansion, cytokine secretion, RNA profiles, cytotoxicity against tumor lines, and cell surface phenotypes. Expanded CD19 NK donors with varying numbers of activating KIR vs inhibitory KIR were tested for effector function, and these donors were then tested for in vivo efficacy and pharmacokinetics. A KIR ranking score was developed by considering both the number of activating and inhibitory KIR genes expressed by each donor. This score was correlated with functional properties of CAR NK cells.ResultsAddition of 12–18 to the K562-mbIL15-41BBL stimulatory cells improves CD19-CAR NK potency 2-fold relative to the stimulatory cell line alone (P=.02) while NK cell expansion is unchanged. 12–18 also drove an increase in effector cytokine accumulation on exposure of CAR-NK to CD19 tumor. CIML CAR NK cells from donors with higher KIR scoring also had higher cytotoxicity (Pearson’s R=0.74, P=0.006); this correlation was not observed following expansion in the absence of 12–18. 12–18 also drove more potent in vivo activity against tumor with an increased presence of circulating NK cells over 4 weeks in the mice.ConclusionsCIML CAR NK cells derived from donors with favorable KIR scoring have greater cytotoxic activity, effector cytokine production, and in vivo pharmacokinetics and efficacy. These findings may provide an important criterion for donor selection in the development of more robust and potent engineered NK cells for clinical use.ReferencesLapteva N, Durett AG, Sun J, Rollins LA, Huye LL, Fang J, Dandekar V, Mei Z, Jackson K, Vera J, Ando J, Ngo MC, Coustan-Smith E, Campana D, Szmania S, Garg T, Moreno-Bost A, Vanrhee F, Gee AP, Rooney CM. Large-scale ex vivo expansion and characterization of natural killer cells for clinical applications. Cytotherapy 2012;14(9):1131–1143.Chihaya I, Iwamoto S, Campana D. Genetic modification of primary natural killer cells overcomes inhibitory signals and induces specific killing of leukemic cells. Blood 2005;106:376–383.Yang Y, Connolly J, Shimasaki N, Mimura K, Kono K, Campana D. A Chimeric Receptor with NKG2D Specificity Enhances Natural Killer Cell Activation and Killing of Tumor Cells. Cancer Res 2013;73(6):1777–1786.Romee R, Rosario M, Berrien-Elliott MM, Wagner JA, Jewell BA, Schappe T, Leong JW, Abdel-Latif S, Schneider SE, Willey S, Neal CC, Yu L, Oh ST, Lee YS, Mulder A, Claas F, Cooper MA, Fehniger TA. Cytokine-induced memory-like natural killer cells exhibit enhanced responses against myeloid leukemia. Sci Trans Med 2016;8(357): 357ra123.Cooley S, Weisdorf DJ, Guethlein LA, Klein JP, Wang T, Le CT, Marsh SGE, Geraghty D, Spellman S, Haagenson MD, Ladner M, Trachtenberg E, Parham P, and Miller JS. Donor selection for natural killer cell receptor genes leads to superior survival after unrelated transplantation for acute myelogenous leukemia. Blood 2010;116(14):2414–2419.Cooley S, Weisdorf DJ, Guethlein LA, Klein JP, Wang T, Marsh SGE, Spellman S, Haagenson MD, Saeturn K, Ladner M, Trachtenberg E, Parham P, and Miller JS. Donor Killer Cell Ig-like Receptor B Haplotypes, Recipient HLA-C1, and HLA-C Mismatch Enhance the Clinical Benefit of Unrelated Transplantation for Acute Myelogenous Leukemia. JI, 2014;192(10):4592–600.Ethics ApprovalAnimal studies were conducted with IACUC approval.


2018 ◽  
Vol 17 ◽  
pp. 153601211879481 ◽  
Author(s):  
Mariya Shapovalova ◽  
Sean R. Pyper ◽  
Branden S. Moriarity ◽  
Aaron M. LeBeau

The recent success of autologous T cell-based therapies in hematological malignancies has spurred interest in applying similar immunotherapy strategies to the treatment of solid tumors. Identified nearly 4 decades ago, natural killer (NK) cells represent an arguably better cell type for immunotherapy development. Natural killer cells are cytotoxic lymphocytes that mediate the direct killing of transformed cells with reduced or absent major histocompatibility complex (MHC) and are the effector cells in antibody-dependent cell-mediated cytotoxicity. Unlike T cells, they do not require human leukocyte antigen (HLA) matching allowing for the adoptive transfer of allogeneic NK cells in the clinic. The development of NK cell-based therapies for solid tumors is complicated by the presence of an immunosuppressive tumor microenvironment that can potentially disarm NK cells rendering them inactive. The molecular imaging of NK cells in vivo will be crucial for the development of new therapies allowing for the immediate assessment of therapeutic response and off-target effects. A number of groups have investigated methods for detecting NK cells by optical, nuclear, and magnetic resonance imaging. In this review, we will provide an overview of the advances made in imaging NK cells in both preclinical and clinical studies.


2021 ◽  
Vol 12 ◽  
Author(s):  
Giorgio Santoni ◽  
Consuelo Amantini ◽  
Matteo Santoni ◽  
Federica Maggi ◽  
Maria Beatrice Morelli ◽  
...  

Natural killer (NK) cells are a main subset of innate lymphocytes that contribute to host immune protection against viruses and tumors by mediating target cell killing and secreting a wide array of cytokines. Their functions are finely regulated by a balance between activating and inhibitory receptors and involve also adhesive interactions. Mechanotransduction is the process in which physical forces sensed by mechanosensors are translated into chemical signaling. Herein, we report findings on the involvement of this mechanism that is mainly mediated by actin cytoskeleton, in the regulation of NK cell adhesion, migration, tissue infiltration and functions. Actin represents the structural basis for NK cell immunological synapse (NKIS) and polarization of secretory apparatus. NK-target cell interaction involves the formation of both uropods and membrane nanotubes that allow target cell interaction over long distances. Actin retrograde flow (ARF) regulates NK cell signaling and controls the equilibrium between activation versus inhibition. Activating NKIS is associated with rapid lamellipodial ARF, whereas lower centripetal actin flow is present during inhibitory NKIS where β actin can associate with the tyrosine phosphatase SHP-1. Overall, a better knowledge of mechanotransduction might represent a future challenge: Realization of nanomaterials tailored for NK cells, would be important to translate in vitro studies in in vivo new immunotherapeutic approaches.


2003 ◽  
Vol 197 (8) ◽  
pp. 967-976 ◽  
Author(s):  
Martin Prlic ◽  
Bruce R. Blazar ◽  
Michael A. Farrar ◽  
Stephen C. Jameson

While the specificity and development of natural killer (NK) cells have been intensely studied, little is known about homeostasis of the mature NK population. Here we show that mouse NK cells undergo homeostatic proliferation when transferred into NK-deficient Rag−/− γC−/− hosts. Normal NK functional activity is maintained during this process, although there are some changes in NK phenotype. Using cell sorting, we demonstrate that mature (Mac-1hi) NK cells undergo homeostatic proliferation in an NK-deficient environment, yet immature (Mac-1lo) NK cells also proliferate in such hosts. We find that mature NK cells survive but do not proliferate in hosts which possess an endogenous NK pool. However, we go on to show that mature NK survival is critically dependent on interleukin (IL)-15. Surprisingly, NK survival is also compromised after transfer of cells into IL-15Rα−/− mice, implying that IL-15 responsiveness by bystander cells is critical for NK maintenance. These data imply that, similar to T cells, homeostasis of the NK pool is much more dynamic than previously appreciated and this may be relevant to manipulation of NK cells for therapeutic purposes.


2000 ◽  
Vol 191 (8) ◽  
pp. 1341-1354 ◽  
Author(s):  
Hamish R.C. Smith ◽  
Hubert H. Chuang ◽  
Lawrence L. Wang ◽  
Margarita Salcedo ◽  
Jonathan W. Heusel ◽  
...  

Murine natural killer cells (NK) express lectin-like activation and inhibitory receptors, including the CD94/NKG2 family of receptors that bind Qa-1, and the Ly-49 family that recognizes major histocompatibility complex class I molecules. Here, we demonstrate that cross-linking of NK cells with a new specific anti–Ly-49H mAb induced NK cell cytotoxicity and cytokine production. Ly-49H is expressed on a subset of NK cells and can be coexpressed with Ly-49 inhibitory receptors. However, unlike Ly-49 inhibitory receptors, Ly-49H is not detectable on naive splenic CD3+ T cells, indicating that Ly-49H may be an NK cell–specific activation receptor. In further contrast to the stochastically expressed Ly-49 inhibitory receptors, Ly-49H is preferentially expressed with the Ly-49D activation receptor, and expression of both Ly-49H and Ly-49D is augmented on NK cells that lack receptors for Qa-1 tetramers. On developing splenic NK1.1+ cells, Ly-49D and Ly-49H are expressed later than the inhibitory receptors. These results directly demonstrate that Ly-49H activates primary NK cells, and suggest that expression of Ly-49 activation receptors by NK cells may be specifically regulated on NK cell subsets. The simultaneous expression of multiple activation receptors by individual NK cells contrasts with that of T cell antigen receptors and is relevant to the role of NK cells in innate immunity.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 341-341
Author(s):  
Lucila Kerbauy ◽  
Mecit Kaplan ◽  
Pinaki P Banerjee ◽  
Francesca Lorraine Wei Inng Lim ◽  
Ana Karen Nunes Cortes ◽  
...  

Abstract Chimeric antigen receptors to redirect T cell specificity against tumor antigens have shown remarkable clinical responses against CD19+ malignancies. However, the manufacture of an engineered autologous T cell product is expensive and cumbersome. Natural killer (NK) cells provide an alternative source of immune effectors for the treatment of cancer. NK cell cytolytic function can be directed towards specific targets by exploiting their ability to mediate antibody-dependent cellular cytotoxicity (ADCC) through the NK cell Fc receptor, CD16 (FcγRIIIa). AFM13 is a tetravalent bispecific antibody construct based on Affimed's ROCK™ platform. AFM13 is bispecific for CD30 and CD16A, designed for the treatment of CD30 expressing malignancies. It binds CD16A on the surface of NK cells, thus activating and recruiting them to CD30 expressing tumor cells and mediating subsequent tumor cell killing. Since autologous NK effector function is impaired in many patients with malignancies, we propose to overcome this by the use of allogeneic NK cells in combination with AFM13. Cord blood (CB) is a readily available ("off-the-shelf") source of allogeneic NK cells that can be expanded to large, highly functional therapeutic doses. The feasibility and safety of therapy with allogeneic ex vivo expanded CB-derived NK cells have been shown by our group and others. In this study, we hypothesized that we can redirect the specificity of NK cells against CD30+ malignancies by preloading ex vivo activated and expanded CB-derived NK cells with AFM13 prior to adoptive infusion. Briefly, mononuclear cells were isolated from fresh or frozen CB units by ficoll density gradient centrifugation. CD56+ NK cells were cultured with rhIL-12, rhIL-18 and rhIL-15 for 16 hrs, followed by ex vivo expansion with rhIL-2 and irradiated (100 Gy) K562-based feeder cells expressing membrane-bound IL-21 and CD137-ligand (2:1 feeder cell:NK ratio). After 14 days, NK cells were loaded with serial dilutions of AFM13 (0.1, 1, 10 and 100 mg/ml). After washing twice with PBS, we tested the effector function of AFM13-loaded NK-cells (AFM13-NK) compared to expanded CB-NK cells without AFM13 against Karpas-299 (CD30 positive) and Daudi (CD30 negative) lymphoma cell lines by 51Cr release and intracellular cytokine production assays. AFM13-NK cells killed Karpas-299 cells more effectively at all effector:target ratios tested than unloaded NK cells (Figure 1) and produced statistically more INFγ and CD107a (P=0.0034; P=0.0031 respectively, n=4). In contrast, AFM13-NK cells and unloaded NK cells exerted similar cytotoxicity against Daudi cells. Next, we established the optimal concentration of AFM13 for loading (determined to be 100 μg/ml) and the optimal incubation time to obtain maximal activity (1 h) in a series of in vitro experiments. We also confirmed that the activity of AFM13-NK cells against Karpas-299 cells remains stable for at least 72h post-wash (Figure 2). Additionally, we characterized the phenotype of AFM13-NK vs. unloaded NK cells by flow cytometry using monoclonal antibodies against 22 markers, including markers of activation, inhibitory receptors, exhaustion markers and transcription factors. Compared to unloaded NK cells, AFM13-NK cells expressed higher levels of CD25, CD69, TRAIL, NKp44, granzyme B and CD57, consistent with an activated phenotype. We next tested the in vivo anti-tumor efficacy of AFM13-NK cells in an immunodeficient mouse model of FFluc-Karpas-299. Briefly, six groups of NOD/SCID/IL2Rγc null mice (n=5 per group) were transplanted by tail-vein injection with 1 x 10e5 FFluc-transduced Karpas cells. Group 1 and 6 received tumor alone or tumor + AFM13 and served as a control. Groups 2-4 receive Karpas FFLuc with either expanded NK cells or AFM13-NK cells (NK cells loaded with AFM13) or expanded NK cells and AFM13 injected separately. Group 5 received AFM13-NK cells without tumor. Initial studies confirm the antitumor activity of AFM13-NK cells. In summary, we have developed a novel premixed product, comprised of expanded CB-NK cells loaded with AFM13 to 'redirect' their specificity against CD30+ malignancies. The encouraging in vitro and in vivo data observed in this study, provide a strong rationale for a clinical trial to test the strategy of an off-the-shelf adoptive immunotherapy with AFM13-loaded CB-NK cells in patients with relapsed/refractory CD30+ malignancies. Disclosures Champlin: Sanofi: Research Funding; Otsuka: Research Funding. Koch:Affimed GmbH: Employment. Treder:Affimed GmbH: Employment. Shpall:Affirmed GmbH: Research Funding. Rezvani:Affirmed GmbH: Research Funding.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 551-551 ◽  
Author(s):  
Martin Felices ◽  
Alexander Lenvik ◽  
Sami Chu ◽  
Ron McElmurry ◽  
Sarah Cooley ◽  
...  

Abstract Natural Killer (NK) cells represent an exciting immunotherapeutic approach to treat cancer. We have shown that in vivo expansion and activation of donor NK cells supported by administration of IL-2 induces remission in patients with refractory AML. Recent clinical studies by our group have shown that IL-15 is superior to IL-2 to support NK cell persistence 14 days after adoptive transfer. However, only 36% of patients treated with 12 consecutive days of IL-15 had NK cell expansion to the level of ≥100 donor derived NK cells/µL blood compared to 10% in subjects treated with IL-2 (p=0.02). This leads us to conclude that we might not know the optimal route and interval to administer in vivo IL-15. We hypothesized that daily uninterrupted IL-15 dosing could lead to exhaustion or NK cellular stress. Therefore we designed an in vitro model system in which enriched NK cells are treated with three 3-day cycles of continuous IL-15 (IL-15cont) or were rested with a "gap" (skipping the middle cycle [IL-15gap]) before returning to the last cycle of IL-15. IL-15cont treatment yielded more proliferation and higher cell numbers compared to IL-15gap (4.8±0.44 vs. 1.9±0.26 million cells/ml, p < 0.0001) when cells were analyzed at the end of the three cycles (on day 9, where all in vitro measurements were taken). However, NK cell death, measured by flow cytometry, in the IL-15cont group was higher (18.9±2.2 vs 14.9±1.7 % cell death, p = 0.035) and this group also had an enrichment in genes involved in cell cycle checkpoint/ arrest, perhaps indicating more cellular stress in the IL-15cont. In an in vitro flow cytometric functional assay, the IL-15cont group had decreased activation when compared to the IL-15 gap group against K562 targets (43.6±2.1 vs 55.6±2.7 % CD107a [degranulation], p < 0.0001; 1.9±0.41 vs 7.1±0.93 % IFNg [inflammatory cytokine production], p = 0.0055). The decrease in NK cell activation correlated with a strong decrease in tumor target killing in an in vitro chromium release assay (Figure 1A) measuring killing of acute promyelocytic leukemia (HL-60) cell targets, in which the IL-15cont NK cells were potently outperformed by the IL-15gap cells (6.4±2.6 vs 51.5±4.8 % killing at 2.5:1 effector:target ratio, p < 0.0001). We used an in vivo xenogeneic model of AML, where conditioned NSG (NOD scid gamma) mice are engrafted with HL-60luc tumor targets 3 days prior to infusion with nothing, IL-15cont or IL-15gap human NK cells prepared within our 9 day culture system. Only the IL-15gap NK group mediated statistically significant tumor control when compared to tumor alone at two weeks following NK cell infusion (Figure 1B). To probe deeper into the functional defect we evaluated signaling after these treatments and noted decreased phosphorylation of several proteins in the IL-15cont group. These data led us to explore proteins involved in metabolism and we noted that CPT1A, a critical enzyme involved in fatty acid oxidation (FAO), was strongly increased in the IL-15gap treated NK cells (protein MFI of 15,759±2,603 [IL-15gap] vs 5,273±744 [IL-15cont], p = 0.009). Metabolic analysis using a Seahorse XFe24 analyzer showed an increased mitochondrial spare respiratory capacity (SRC) in the IL-15gap group, denoting better capability of the IL-15gap NK cells to respond to energetic demands (Figure 1C). In a separate experiment the groups were treated with etomoxir to inhibit CPT1A, and the SRC phenotype was reversed, with the IL-15gap group containing lower SRC than the IL-15cont group. To test these findings in a functional assay we repeated the IL-15cont treatment in combination with rapamycin, which can induce CPT1A through inhibition of mTORC1, and saw restoration of function to levels similar to IL-15gap (40.8±2.0 vs 49.3±2.9 % CD107a in the IL-15cont vs IL-15cont + rapamycin, p = 0.005; 2.4±0.47 vs 4.8±1.0 % IFNg in the IL-15cont vs IL-15cont + rapamycin, p = 0.03). These data indicate that NK cell functional exhaustion via continuous IL-15 signaling is mediated by a decrease in FAO. Intermittent IL-15 dosing or altering metabolism through other mechanisms may overcome this competition. These findings could impact ongoing clinical trials through simple alterations in dosing strategies in order to minimize NK cell exhaustion in the immunotherapeutic setting. Disclosures Cooley: Fate Therapeutics: Research Funding. Miller:Oxis Biotech: Consultancy, Other: SAB; Fate Therapeutics: Consultancy, Research Funding.


2016 ◽  
Vol 1 (3) ◽  
pp. 208-218 ◽  
Author(s):  
Rachel J. Bergerson ◽  
Robin Williams ◽  
Hongbo Wang ◽  
Ryan Shanley ◽  
Gretchen Colbenson ◽  
...  

Key Points Low numbers of reconstituting NK cells at D+28 after dUCBT are associated with inferior DFS. Patients with low NK cell numbers at D+28 have reduced phosphorylation of STAT5 upon IL-15 stimulation and less Eomes expression.


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