The Role of Her2/Neu in ALL: Long Term Clinical Follow-up of Surface-Positive Patients and Induction of NK Cell ADCC by Trastuzumab in Vitro

Abstract Abstract 1421 In about one third of patients, acute lymphoblastic leukemia (ALL) cells express Her2/neu (p185Her-2). In epithelial malignancies Her2/neu contributes to oncogenic transformation and metastatic potential, and overexpression often is associated with poor prognosis. Previous reports also suggested an inferior prognosis in patients with Her2/neu-positive ALL, but as of now no study has performed survival analyses. In breast cancer patients, targeting of Her2/neu with the monoclonal antibody Trastuzumab results in improved disease outcome, and induction of antibody dependent cellular cytotoxicity (ADCC) and cytokine release of NK cells contributes to the same. Most recently, application of Trastuzumab in patients with relapsed or refractory ALL was shown to yield promising results, but the mechanisms by which Trastuzumab mediates its efficacy have not been studied so far. Here, we studied patient records and flow cytometry data on Her2/neu expression of patients treated for ALL at our hospital between 2000 and 2011 and determined the effect of Trastuzumab and/or Rituximab on NK cell reactivity against ALL blasts in vitro. In 57 patients (37 men, 20 women, median age at diagnosis 42 years, range 17–83 years) data on Her2/neu expression were available. Her2/neu expression was detected in 15/57 patients (26%). Clinical follow up was assessed for all 57 patients. Median follow-up was 44 months (range 0.5–356 months) until death or last follow-up visit. Overall, 60% of the patients had died at the end of follow-up (25 of 42 Her2/neu-negative and 9 of 15 Her2/neu-positive patients, respectively). Median survival times were 43 (Her2/neu-negative, range 0.5–356 months) and 41 months (Her2/neu-positive, range 3.5–138 months; p = 0.81. Kaplan Meyer regression analysis). Also, median time to relapse was comparable in both groups (22.5 months vs. 15.5 months; p = 0.77). In functional analyses with NK cells, incubation of Her2/neu-positive CD20-positive ALL blasts with Trastuzumab or Rituximab comparably induced ADCC and cytokine release of NK cells. Only minor additional effects were observed upon combined application of both antibodies. When blasts from Her2/neu-negative ALL patients were employed (phentotype CD20-positive Her2/neu-negative or CD20-negative Her2/neu-negative), no effect of Trastuzumab was observed, and Rituximab exerted effects solely with blasts from CD20-positive ALL patients. Taken together, in our patient cohort Her2/neu expression on ALL blasts was not associated with time to relapse or overall survival and thus did not appear to be an additional risk factor. Rather, Her2/neu is a promising target for antibody therapy, especially in patients with Her2/neu-positive CD20-negative ALL, as treatment with Trastuzumab is suitable to induce ADCC and cytokine production of NK cells also against Her2/neu-positive CD20-negative ALL blasts. Disclosures: No relevant conflicts of interest to declare.

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Natural Killer Cells In Pediatric Acute Lymphoblastic Leukemia Patients At Diagnosis Demonstrate An Inhibitory Phenotype and Reduced Cytolytic Capacity

Blood ◽

10.1182/blood.v122.21.1397.1397 ◽

2013 ◽

Vol 122 (21) ◽

pp. 1397-1397 ◽

Cited By ~ 1

Author(s):

Rayne H. Rouce ◽

Takuya Sekine ◽

Gerrit Weber ◽

Claude Chew ◽

Katayoun Rezvani ◽

...

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Nk Cells ◽

Nk Cell ◽

Lymphoblastic Leukemia ◽

Target Cells ◽

Healthy Controls ◽

Cytokine Release ◽

Absolute Count ◽

Flow Cytometric ◽

Pediatric All

Abstract Background Natural killer (NK) cells are a key component of innate immunity, with the potential to recognize and kill transformed malignant cells without prior sensitization. A balance between activating and inhibitory signals from cell surface receptors determines NK cell cytotoxicity and cytokine release. Therapeutic approaches to augmenting NK cell function are being explored in various malignancies. Little is known about NK phenotype and function in patients with childhood acute lymphoblastic leukemia (ALL), the most common childhood cancer. Here we describe an inhibitory phenotype and impaired cytolytic function in NK cells from pediatric ALL patients at diagnosis, compared with healthy pediatric controls. Restoring NK function may be a useful therapeutic approach in ALL. Methods Peripheral blood mononuclear cells (PBMCs) were isolated from 25 patients with newly diagnosed B-ALL, age 1-16 years, and 7 healthy controls, age 2-13 years, in order to compare NK cell frequency, immunophenotype, and functional activity. NK frequency was assessed by flow cytometric staining for CD56+CD3- cells. NK phenotype was assessed by surface expression of activating receptors NKp30, NKp44, NKp46 and NKG2D and inhibitory receptors KIR2DL1/S1, KIR2DL2/S2, KIR3DL1 and NKG2A. Functional activity was determined by incubation of NKs with target cells, followed by flow cytometric measurement of degranulation (surface CD107a) and cytokine release (intracellular IFNg and TNFa). Targets included the MHC class I deficient K562 cell line and, where available, autologous ALL blasts. Results ALL patients demonstrated significantly lower absolute NK cell counts compared with healthy controls (mean absolute count 168 vs. 406 cells/uL, p = 0.0002). They also exhibited significantly fewer NK cells expressing the activating marker NKp46 (mean absolute count 70 vs. 165, p = 0.016); and a significantly higher percentage of cells expressing the inhibitory marker NKG2A (mean 20.5% vs. 1.95% in controls, p = 0.012) (Fig 1A). In co-culture assays with K562 target cells, ALL patients' NK cells demonstrated inferior degranulation and cytokine release compared to healthy controls (representative data in Fig 1B; mean IFNγ production of 1.2% vs. 4.8%, p = 0.02; mean TNFα production of 1.8% vs. 3.8%, p = 0.06; and mean surface CD107a of 5.4% vs. 15.1%, p = 0.08). ALL samples (n = 3) demonstrated little to no cytokine release when incubated with autologous blasts compared with the response elicited by PMA-ionomycin (representative data in Fig 1C; mean CD107a 0.92% vs. 7.85%, p = 0.04; mean IFNγ 0.26% vs 40.47%, p = 0.10; mean TNFα 0.2% vs 41%, p = 0.008). Conclusion At diagnosis, pediatric ALL patients exhibit a lower frequency of NK cells, an inhibitory phenotype, and decreased cytolytic activity compared to healthy pediatric controls, particularly against autologous leukemic blasts. These results suggest that augmentation of the NK response may be useful therapeutically to improve outcomes in childhood ALL. Disclosures: No relevant conflicts of interest to declare.

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Costimulatory Effects of Interleukin-18 (IL-18) on Human Natural Killer (NK) Cells Activated through Fc Receptors for Immunoglobulin (IgG)

Blood ◽

10.1182/blood.v116.21.2780.2780 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2780-2780

Author(s):

Shivani Srivastava ◽

Hailin Feng ◽

Menggang Yu ◽

David Pelloso ◽

Michael Robertson

Keyword(s):

Monoclonal Antibodies ◽

Nk Cells ◽

Cell Function ◽

Nk Cell ◽

Conflicts Of Interest ◽

Fc Receptors ◽

Cytolytic Activity ◽

Mitogen Activated Protein Kinase ◽

Target Cells

Abstract Abstract 2780 NK cells play an important role in innate and adaptive immune responses. Most human NK cells express CD16, an Fc receptor for IgG that mediates lysis of antibody-coated target cells and costimulates interferon (IFN)-g production in response to cytokines. IL-18 is an immunostimulatory cytokine with antitumor activity in preclinical animal models. The effects of IL-18 on human NK cell function were examined. Here we show that NK cells stimulated with immobilized IgG in vitro secreted IFN-g; such IFN-g production was partially inhibited by blocking CD16 with monoclonal antibodies. IL-18 augmented IFN-g production by NK cells stimulated with immobilized IgG or CD16 antibodies (Figure 1). NK cell IFN-g production in response to immobilized IgG and/or IL-18 was inhibited by chemical inhibitors of Syk, extracellular signal-related kinases (ERK), p38 mitogen-activated protein kinase (MAPK), and phosphatidylinositol 3-kinase (PI3-K). Stimulation with IL-18 or immobilized IgG could augment IL-12-induced IFN-g production by STAT4-deficient lymphocytes obtained from lymphoma patients after autologous stem cell transplantation (Figure 2). IL-18 also augmented the in vitro lysis of rituximab-coated Raji cells by human NK cells (Figure 3). These observations that IL-18 can co stimulate IFN-g production and cytolytic activity of NK cells activated through Fc receptors makes it an attractive cytokine to combine with monoclonal antibodies for treatment of cancer. Disclosure: No relevant conflicts of interest to declare.

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Obinutuzumab (GA101) Significantly Enhances Cell Death and ADCC Compared to Rituximab Against CD20+ sensitive and Rituximab Resistant B-Cell Non-Hodgkin Lymphoma (NHL) and Lymphoblastic Leukemia (BLL)

Blood ◽

10.1182/blood.v120.21.4865.4865 ◽

2012 ◽

Vol 120 (21) ◽

pp. 4865-4865 ◽

Cited By ~ 1

Author(s):

Aradhana Awasthi Tiwari ◽

Janet Ayello ◽

Carmella van de Ven ◽

Danielle Glassman ◽

Anthony Sabulski ◽

...

Keyword(s):

Cell Death ◽

B Cell ◽

Nk Cells ◽

Cell Lines ◽

Caspase 3 ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Dismal Prognosis

Abstract Abstract 4865 Background: Patients who relapse with CD20+ B-NHL and B cell lymphoblastic leukemia (B-LL) have a dismal prognosis, often associated with chemotherapy resistance (Cairo et al. JCO, 2012,Mils/Cairo et al. BJH,2012) and often require alternative therapeutic strategies. Rituximab (RTX) in combination with FAB 96 chemotherapy is a safe, well-tolerated treatment that is associated with > 90% EFS in children with newly diagnosed and advanced mature B-Cell NHL (Cairo M.S. et al. ASCO, 2010). Resistance to RTX, however, may predispose patients with CD20+ NHL to an increase risk of relapse and or disease progression (Barth/Cairo et al. BJH, 2012; Tsai et al. Cl. Can. Res, 2012). Obinutuzumab (GA101), a novel type II glycoengineered CD20 antibody of the IgG1 isotype, mediates enhanced cell death vs RTX and has a glycoengineered Fc region that induces significantly enhanced ADCC (Mössner et al. Bld, 2010; Niederfellner G. et al. Bld, 2011; Bologna L et al. JI, 2012). Objective: To evaluate the in-vitro efficacy of GA101 compared to RTX against RTX sensitive and resistant CD20+ B-NHL and B-LL cell lines. Methods: Raji (CD20+,ATCC, Manhass, VA), U698-M (CD20+, DSMZ, Germany), Loucy cells (CD20−) (T-ALL) (ATCC, Manhass, VA) and Raji-2R and Raji-4RH (generously supplied by M. Barth, Roswell Park Cancer Institute) were cultured in RPMI with 10% FBS and incubated with GA101 and/or RTX at 100 μg/ml for 24 hrs (n=6), 48 and 72 hrs (n=5). Cell death was evaluated by staining with AnnexinV/7AAD and flow-cytometry. Loucy cells (CD20−) were used as the negative control. The caspase 3/7 activity was measured by FAM caspase 3/7 assay kit by FLICA™ methodology. RSCL, RRCL, U698-M and Loucy were incubated with GA101 and RTX treatment for 24, 48 and 72 hrs, and caspase3/7 activity was detected by FACS using 488 nm excitation and emission filter (n=3). ADCC were performed with K562-IL-15–41BBL expanded NK cells (Ayello/Cairo et al. ASH, 2010) as well as IL-2 expanded NK cells, at 20:1 effector: target ratio (E: T, n=3) using europium release assay (Perkin-Elmer). Results: GA101 induced significantly more cell death compared to RTX in B-NHL and BLL cell lines. (Table-1) GA101 vs RTX shows a significantly increase in caspase 3/7 activity in Raji 16.92±0.84% vs 11.76±0.08% compared to Raji2R 6.7±0.62% vs 2.8±0.7%, Raji4RH 5.8±0.35% vs 2.0±0.3% and U698-M 12.54±0.44% vs 9.6±0.95% compared to Loucy 3.22±0.45% vs 2.59±0.05%, respectively, at 24 hrs of treatment (p<0.0001). GA101 vs RTX also elicited a significant increase a ADCC with K562-IL15–41BBL expanded NK cells, in Raji 73.8±8.1% vs 56.81±4.6% compared to Raji-2R 38.0±2.0% vs 21.6±1.2%, Raji-4RH 40.0±1.6% vs 0.5±1.1% and U698-M 70.0±1.6% vs 45.56±0.1%, compared to Loucy 21.67±0.48% vs 15.92±0.52%, respectively (p<0.001) at day 7.The IL-2 alone expanded Hu-NK cells demonstrated a reduction of 10–20% cytotoxicity compared to K562-IL15–41BBL Hu-NK cells at day 7 against BLL, RSCL and RRCL, in-vitro. Conclusion: Obinutuzumab compared to RTX significantly enhanced cell death, caspase3/7 activity and NK mediated ADCC in sensitive and RTX resistant B-NHL and B-LL. Obinutuzumab represents a promising candidate for treating RTX sensitive and resistant CD20+ B-Cell Lymphomas and lymphoblastic leukemia. Further studies will investigate the combination of activated NK cells or chemotherapy that may enhance or synergize with the efficacy of GA101 (Obinutuzumab) both in -vitro and in-vivo in xenografted NOD/SCID mice. Disclosures: No relevant conflicts of interest to declare.

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41BBL-Based Activation and Expansion of Autologous Natural Killer Cells Results in Enhanced Activity Against Leukemia Including ALL

Blood ◽

10.1182/blood.v124.21.2293.2293 ◽

2014 ◽

Vol 124 (21) ◽

pp. 2293-2293

Author(s):

Ekta Kapadia ◽

Elad Jacoby ◽

Mark Kohler ◽

Waleed Haso ◽

Christopher Daniel Chien ◽

...

Keyword(s):

Nk Cells ◽

Natural Killer ◽

Nk Cell ◽

Conflicts Of Interest ◽

Ex Vivo ◽

Lymphoblastic Leukemia ◽

Myelogenous Leukemia ◽

Hematopoietic Stem ◽

Enhanced Activity

Abstract Childhood leukemia is the most common pediatric malignancy. There are now excellent cure rates for these patients, however outcomes remain poor for those with refractory disease and for those who relapse after standard salvage therapies, with a disease recurrence of approximately 50%. Therefore, development of novel cellular therapies is essential to treat these refractory patients. Natural Killer (NK) cells generated from an allograft contribute to improved disease free survival after Hematopoietic Stem Cell Transplantation for leukemia when there is a KIR mismatch. This effect appears to be particularly potent in the setting of Acute Myelogenous Leukemia (AML) with less benefit demonstrated in Acute Lymphoblastic Leukemia (ALL). Preclinical studies have also suggested that activation and expansion of resting NK cells can enhance NK cell cytotoxicity and eliminate the need for KIR mismatch due to up-regulation of activating receptors. We are currently testing this approach in the clinic following a fully matched allogeneic transplant platform for leukemia. Our aim is to explore whether 41BB ligand (41BBL) and recombinant IL-15 (rIL-15) mediated ex vivo expansion of autologous NK cells results in enhanced activity against AML and ALL. The activation/expansion process may allow for the use of autologous NK cell infusions, thus eliminating the need for allogeneic NK cell donors. To test this hypothesis, we ex vivo expanded and activated NK cells derived from C57BL/6J (B6) mice using artificial Antigen Presenting Cells (aAPCs) containing 41BBL and rIL-15 for 7-14 days. NK cells were co-cultured with murine AML cells (C1498) and murine ALL cells (E2A-PBX) – both on B6 background. Controls included YAC cells (murine T-cell lymphoma cell line sensitive to NK cell killing) as well as Phorbol Myristate Acetate (PMA)/ionomycin. All cells were co-cultured for 5 hours prior to functional assessment of NK cells via CD107a degranulation. NK cells cultured with 41BBL aAPCs and rIL-15 had a 30-fold expansion in numbers (Figure 1) and an increase in purity to approximately 95-98% (NK1.1+, CD3–) by Day 7. In the absence of cytokine or aAPCs, cultured NK cells underwent rapid apoptosis. Functionally, although resting NK cells (harvested prior to assessment) expressed CD107a when cultured with YAC cells and PMA, only minimal degranulation was observed in the presence of autologous AML cells or ALL cells. In contrast, activated and expanded autologous NK cells displayed enhanced activity against ALL, AML, as well as YAC cells, while only minimal levels of CD107a were seen in the absence of targets (Figure 2). In vivo experiments with a single injection of activated and expanded NK cells did not result in prolonged survival of mice bearing either AML or ALL. Assessment of adoptively transferred NK cells demonstrated very transient persistence (<2 days) with no in vivo expansion, suggesting that repeated injections may be necessary for leukemia eradication. Future murine experiments will investigate the effect repeated injections of activated/expanded NK cells and/or the administration of rIL-15 will have on survival and leukemia eradication. In addition, the ability to activate and expand NK cells in culture provides an opportunity for lentiviral-based transduction with chimeric antigen receptor (CAR) vectors. We are currently testing this with a murine CD19 CAR. These experiments suggest that autologous activated and expanded NK cells may serve as a viable cellular therapy for pediatric patients with refractory/relapsed leukemia. As demonstrated in these in vitro experiments, autologous activated/expanded NK cells still show increased targeting of mouse AML and ALL cell lines despite the lack of KIR mismatch. Thus, they may serve as a potential platform for leukemia therapy, including ALL, which appear to be poor targets for resting NK cells. In addition, these cells demonstrate transient persistence in vivo, a potential advantage in the context of redirected cytotoxicity using CAR constructs that target antigens with broader expression in the hematopoietic compartment. Figure 1: <![if !vml]><![endif]> Figure 1:. <![if !vml]><![endif]> Figure 2: Figure 2:. Disclosures No relevant conflicts of interest to declare.

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Exploitation of natural killer cells for the treatment of acute leukemia

Blood ◽

10.1182/blood-2015-12-629055 ◽

2016 ◽

Vol 127 (26) ◽

pp. 3341-3349 ◽

Cited By ~ 58

Author(s):

Rupert Handgretinger ◽

Peter Lang ◽

Maya C. André

Keyword(s):

Cell Therapy ◽

Nk Cells ◽

Natural Killer ◽

Adoptive Transfer ◽

Nk Cell ◽

Lymphoblastic Leukemia ◽

Leukemia Cell ◽

Target Cells

Abstract Natural killer (NK) cells play an important role in surveillance and elimination of malignant cells. Their spontaneous cytotoxicity was first demonstrated in vitro against leukemia cell lines, and NK cells might play a crucial role in the therapy of leukemia. NK cell activity is controlled by an array of germ line–encoded activating and inhibitory receptors, as well as modulating coreceptors. This biologic feature can be exploited in allogeneic cell therapy, and the recognition of “missing-self” on target cells is crucial for promoting NK cell–mediated graft-versus-leukemia effects. In this regard, NK cells that express an inhibitory killer immunoglobulin-like receptor (iKIR) for which the respective major histocompatibility complex class I ligand is absent on leukemic target cells can exert alloreactivity in vitro and in vivo. Several models regarding potential donor–patient constellations have been described that have demonstrated the clinical benefit of such alloreactivity of the donor-derived NK cell system in patients with adult acute myeloid leukemia and pediatric B-cell precursor acute lymphoblastic leukemia after allogeneic stem cell transplantation. Moreover, adoptive transfer of mature allogeneic NK cells in the nontransplant or transplant setting has been shown to be safe and feasible, whereas its effectivity needs further evaluation. NK cell therapy can be further improved by optimal donor selection based on phenotypic and genotypic properties, by adoptive transfer of NK cells with ex vivo or in vivo cytokine stimulation, by the use of antibodies to induce antibody-dependent cellular cytotoxicity or to block iKIRs, or by transduction of chimeric antigen receptors.

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NKG2D Gene Polymorphism Is Associated with Disease Control of Chronic Myeloid Leukemia By Dasatinib

Blood ◽

10.1182/blood.v128.22.3091.3091 ◽

2016 ◽

Vol 128 (22) ◽

pp. 3091-3091

Author(s):

Ryujiro Hara ◽

Makoto Onizuka ◽

Erika Matsusita ◽

Eri Kikkawa ◽

Yoshihiko Nakamura ◽

...

Keyword(s):

Cell Proliferation ◽

Nk Cells ◽

Kinase Inhibitor ◽

Nk Cell ◽

Conflicts Of Interest ◽

Philadelphia Chromosome ◽

Molecular Response ◽

Proliferation Capacity ◽

Deep Molecular Response

Abstract Dasatinib (DA) is a tyrosine kinase inhibitor (TKI), and is approved for the treatment of naïve and relapsed/refractory Philadelphia chromosome positive leukemia. DA is a potent and multi-target TKI, and a part of patients treated with DA are reported to exhibit lymphocytosis and that is caused by a proliferation of NK cells or CD8 T cells. Nowadays, a lot of reports about the stop TKI trials suggested that treatment free remission of the CML after TKI discontinuation was significantly associated with NK cell proliferation in peripheral blood of the patients. So far, little is known about the individual differences in NK cell response among patients treated with Dasatinib. NKG2D is an activating receptor expressed on NK cells. Recently, functional SNP were identified between LNK1 and HNK1 haplotypes of the NKG2D gene. We analyzed the association between patient's NKG2D polymorphism and achievement of the deep molecular response by Dasatinib. We retrospectively investigated thirty-one patients who were treated with Dasatinib for the first-line treatment of CML at Tokai university school of medicine between 2011 and 2015. Patients with HNK1 haplotype tended to achieve MR4.5 more frequently (not significant), and these patients accomplished MR4.5significantly faster than others. Next, we harvested NK cells from healthy volunteers, and investigated NK cell responses by Dasatinib in vitro. There were differences in the degree of NK cell proliferation capacity among subjects after DA treatment in vitro. We found that NK cells with NKG2D LNK1/LNK1 haplotype exhibited significantly lower proliferation capacity than others in the population. NK cells of higher proliferation capacity exhibited Vav-1 Tyr174 phosphorylation, but they didn't show any differences in cytotoxicity capacity. In this study, our data suggest that DA may stimulate NK cells with NKG2D HNK1 haplotype more strongly than LNK1 haplotype, and therefore patients with HNK1 haplotype can achieve deep molecular response faster than others. So, personalized medicine according to their NKG2D haplotype may be useful to the treatment of CML, especially when they are considered to discontinue DA in stop TKI trials. Disclosures No relevant conflicts of interest to declare.

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Expanded Natural Killer (NK) Cells for Immunotherapy: Fresh and Made to Order

Blood ◽

10.1182/blood.v120.21.1912.1912 ◽

2012 ◽

Vol 120 (21) ◽

pp. 1912-1912

Author(s):

Susann Szmania ◽

Natalia Lapteva ◽

Tarun K. Garg ◽

Joshuah D Lingo ◽

Amy D Greenway ◽

...

Keyword(s):

High Risk ◽

Nk Cells ◽

Mononuclear Cells ◽

Nk Cell ◽

Conflicts Of Interest ◽

K562 Cells ◽

Clinical Grade ◽

Additional Advantage

Abstract Abstract 1912 Introduction Remarkable increases in the dose and activity of NK cells can be achieved by co-culture with the HLA class I deficient cell line K562 that has been genetically modified to express membrane-bound IL15 and the co-stimulatory molecule 41BB-ligand (K562-mb15-41BBL; Fujisaki et al. Cancer Res. 2009;69:4010–4017). We are conducting a clinical trial utilizing these ex-vivo expanded NK cells (ENK) which are produced at the Center for Cell and Gene Therapy (CAGT) at Baylor and then shipped to the University of Arkansas for Medical Sciences (UAMS) for infusion to high-risk relapsed multiple myeloma (MM) patients using the NHLBI-PACT mechanism. Here we report on the characteristics of the ENK cell products sent fresh versus frozen. Methods Apheresis products were collected from MM patients or healthy donors (HD), cryopreserved, and then shipped to CAGT for GMP grade production, as described (Lapteva et al. Cytotherapy 2012; in press). Briefly, mononuclear cells from thawed and ficolled apheresis products were cultured in Stem Cell Growth Medium (CellGenix) supplemented with 10% fetal bovine serum and 10 U/mL IL2 with stimulator cells at a ratio of 1 NK cell to 10 irradiated K562-mb15-41BBL cells (developed at St. Jude Children's Research Hospital, Memphis, TN). Cells were harvested on day 8–9; products from HD were CD3-depleted. Clinical-grade products were shipped to UAMS overnight either cryopreserved in a dry shipper (n=7) or fresh in 5% human serum albumin on cold packs at 1–11°C (n=4). Cell purity, expression of activating molecules, and viability by 7AAD exclusion was assessed by flow cytometry. Standard 4h chromium-release assays were used to assess potency against K562 cells at a 20:1 ENK: K562 ratio. Student's t-Test was used to determine significance. Results From 0.9–1.5×107 starting NK cells, the total number of ENK cells produced was 5.4×109 (range 1.8–24×109). The fold NK-cell expansion was significantly lower for MM patients (n=5, median 22, 12–70 fold) than for HD (n=6, median 95, 31–160 fold; p<0.05). At harvest, median CD3+/CD56+ NK cell purity was 70% (52–88); CD3 depletion of HD products increased CD3+/CD56+ purity to 93% (86–95) resulting in a median CD3+/CD56- T cell content of 0.02% (0.04–1.02). Overall, median viability was 93% (67–98) and potency (defined as lysis of K562 cells at a 20:1 E:T ratio) was 74% (26–92). One product derived from a patient with 21% CD138+ MM cells in the apheresis collection had low expansion (12-fold), viability (66.7%) and potency (26%). For cryopreserved products, viability immediately after thawing was acceptable (median 94%, 75–99) but recovery of viable cells varied from 61% to 100% and thawed ENK failed to lyse K562 cells unless rested overnight. Further, recovery was extremely poor after overnight incubation (median 16%, 10–21). We therefore validated shipment of fresh ENK products. In contrast with frozen NK cells, the median recovery for fresh clinical products post-shipping was 101% (87–151). We confirmed that NK purity, viability, potency and expression of the key activating molecules NKG2D, NKp30, NKp44 and CD226 were retained up to 48h after transfer. ENK further increased by 34% after 72h in vitro incubation in the presence of IL2. Significant in vivo expansion of ENK was observed after infusion of fresh ENK cell products (n=3) but not after infusion of thawed products (n=3, see separate abstract). An additional advantage was that the fresh cells arrived ready to infuse and changes in release criteria relying on rapid and in process testing significantly reduced the time from apheresis collection to ENK infusion, an important consideration when treating high-risk MM patients who can experience rapid disease progression. Conclusion We conclude that large numbers of clinical grade ENK cells can be generated from both MM patient and HD derived apheresis products by co-culture with IL2 and K562-mb15-41BBL although less vigorous expansion was observed with patient-derived cells. Upon thawing, cryopreserved ENK cells exhibited inferior recovery and potency, and survived poorly during further in vitro culture. In contrast, freshly formulated and shipped ENK cells have excellent recovery and retain cytolytic ability. Robust in vivo expansion was only seen after infusion of fresh ENK cells. Production assistance by CAGT allowed for the rapid implementation of a novel therapy utilizing fresh ENK cells for poor prognosis MM patients. Disclosures: No relevant conflicts of interest to declare.

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Human Cytokine-Induced Memory-like (CIML) NK Cells Are Active Against Myeloid Leukemia in Vitro and in Vivo

Blood ◽

10.1182/blood.v124.21.1117.1117 ◽

2014 ◽

Vol 124 (21) ◽

pp. 1117-1117 ◽

Cited By ~ 4

Author(s):

Maximillian Rosario ◽

Rizwan Romee ◽

Stephanie E Schneider ◽

Jeffrey W Leong ◽

Ryan P Sullivan ◽

...

Keyword(s):

Bone Marrow ◽

Nk Cells ◽

Low Dose ◽

Nk Cell ◽

Conflicts Of Interest ◽

K562 Cells ◽

Lymphoid Cells ◽

Ifn Gamma

Abstract NK cells are innate lymphoid cells that mediate anti-leukemia responses. The ability of MHC-haploidentical NK cells to recognize and eliminate AML blasts have been established in the setting of stem cell transplantation and early phase adoptive NK cell immunotherapy trials. However, the optimal approach to prepare human NK cells for maximal anti-leukemia capacity is unclear. As one form of innate NK cell memory, cytokine-induced memory-like (CIML) NK cells are induced by a brief (16 hour) pre-activation of human NK cells with the combination of IL-12, IL-15, and IL-18, while control NK cells from the same donor are activated by IL-15 only. In published work, this combined IL-12, IL-15, and IL-18 pre-activation results in enhanced proliferation and augmented IFN-gamma responses to cytokine or activating receptor-based re-stimulation following a rest period of 1 – 6 weeks. We hypothesized that CIML NK cells exhibit improved anti-leukemia properties compared to control NK cells from the same individual. Purified primary human CIML NK cells [both CD56bright and CD56dim subsets] produce more IFN-gamma, compared to control NK cells, upon re-stimulation with K562 cells or primary AML blasts after 7 days of rest (p<0.05 and p<0.001, N=5). CIML NK cells also exhibit higher granzyme B protein expression (p<0.01; N=8), and increased cytotoxicity against K562 leukemia targets in vitro (p<0.001, 2.5:1 and 5:1 E:T ratios). We next established a NOD-SCID-gamma-c-/- (NSG) xenograft model to investigate primary human CIML NK cell responses in vivo, with survival supported by low dose IL-2 administered every other day. Seven days following injection of 4 million NK cells / mouse, human CIML NK cells traffic to the bone marrow, spleen, liver and blood, and exhibited better in vivo expansion and persistence, compared to control NK cells (p=0.05 in the blood and bone marrow). Further, the characteristic enhanced functionality of CIML compared to control NK cells when restimulated with K562 targets was retained when assessed ex vivo 7 days post-transfer (p<0.05). Next, we investigated the ability of CIML versus control NK cells from the same donor to clear K562 AML cells in vivo. First, luciferase expressing K562 cells (1 million / mouse) were engrafted into sub-lethally irradiated (250 cGy) NSG mice. On day 3 after K562 challenge, primary human CIML or control NK cells from the same donor (4 million / mouse) were injected, which were supported in vivo using low dose IL-2. CIML NK cells exhibited significantly improved in vivo leukemia clearance as evidenced by whole mouse bioluminescence imaging (see Figure, P=0.03, N=7 mice per group). Thus, human CIML NK cells exhibit enhanced in vitro and in vivo anti-leukemia effects, compared to control NK cells. Based on these findings, a first-in-human phase 1 study of CIML NK cells in relapsed/refractory AML is currently underway. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

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Human Natural Killer Cells Are Able to Kill Aspergillus Fumigatus but Not Via the Perforin - Granzyme Pathway.

Blood ◽

10.1182/blood.v114.22.1640.1640 ◽

2009 ◽

Vol 114 (22) ◽

pp. 1640-1640 ◽

Cited By ~ 2

Author(s):

Maria Bouzani ◽

Michael Ok ◽

Oliver Kurzai ◽

Hermann Einsele ◽

Juergen Loeffler

Keyword(s):

Gene Expression ◽

Immune System ◽

Aspergillus Fumigatus ◽

Nk Cells ◽

Innate Immune System ◽

Nk Cell ◽

Surface Expression ◽

Innate Immune ◽

Cytokine Release

Abstract Abstract 1640 Poster Board I-666 Introduction Natural killer (NK) cells are CD3- CD56+ lymphocytes demonstrating confirmed cytotoxicity against neoplastic and virus infected host cells. Increasing data provide evidence of a direct NK cell effect against extracellular pathogens, such as bacteria, parasites and yeasts, but there is a relative lack of data on their interaction with filamentous fungus and especially with Aspergillus fumigatus. Aspergillus is an omnipresent mold, living in close vicinity with humans, being constantly inhaled in the lungs and thereafter cleared by the innate immune system. Otherwise harmless for healthy people, it is at the origin of invasive Aspergillosis (IA), an extremely devastating disease for immunocompromised subjects. Host's innate immune system controls Aspergillus growth through a complex system of potent effector cells, mediating their antifungal activity mainly by phagocytosis. Our study aims to shed light for the first time on the direct interaction between human NK cells, mediators of extracellular cytotoxicity, and Aspergillus. Methods NK cells were isolated after magnetic depletion of the peripheral blood of healthy volunteers and they were used after 24h priming with 500 U/ml recombinant interleukin – 2 rhIL-2. To determine gene expression and cytokine release of interferon gamma (IFNg) and Tumor Necrosis Factor- a (TNF-a), NK cells were stimulated for 0, 3, 6 and 12h with different morphologies of Aspergillus: conidia and germlings. To evaluate the lethal impact of NK cells on Aspergillus, plate killing assays were performed at 0, 3 and 6h time points. To illustrate the role of antibody dependent cellular cytotoxicity, ADCC a monoclonal IgG antibody, against germlings, was tested. Transwell permeable membranes, with pores of 0,4 μm, prohibiting the direct contact of cells placed on their opposite sides, but allowing the free circulation of molecules, were used to estimate the effect of cell-fungal contact. To investigate the cytotoxic mechanism involved, NK cells were depleted from perforin and granzymes by treatment with strontium chloride and they had their death ligands, TNF- related apoptosis- inducing ligand (TRAIL) and FasL, neutralised by means of blocking antibodies. The release of cytotoxic granules was estimated by the NK cell surface expression of the marker of degranulation CD107a/b. Results Observing the in vitro interaction of NK cells with Aspergillus, fungal germinated morphologies (germlings) showed to be highly immunogenic towards NK cells, compared to conidia, inducing the gene expression and cytokine release of Th1 immune mediators such as IFN-g (p <0,05) and TNF-a.(p <0,1). NK cells demonstrated also a strong lethal impact against germlings (p <0,05). Moreover, the presence of antifungal antibody further potentiated both immunoregulatory and cytotoxic activities. Investigating the means engaged by NK cells to perceive and kill Aspergillus, direct effector–pathogen cell to cell contact was revealed as prerequisite; when this condition was not present there was neither cytokine induction, nor fungal damage (p <0,05). This finding was confirmed by the lack of surface expression of CD107a/b, after NK cell- Aspergillus co-incubation. Investigating the killing pathway we compared the effectiveness of perforin – granzymes depleted NK cells to this of intact cells against germlings and it was found equivalent (p =NS). In a similar way, neutralisation of TRAIL and FasL ligands did not alter the cytotoxic ability of NK cells towards Aspergillus. Conclusion Our data show that human NK cells are stimulated in vitro by Aspergillus germlings, which triggers an immunoregulatory Th1 orientated response and causes important fungal killing. NK cells are not aware of conidia, they are not stimulated by them and par consequence they do not kill them. Finally, we showed that NK cells do not mediate their cytotoxic effect via perforin – granzymes pathway, neither through the engagement of TRAIL, FasL death receptors, suggesting that another pathway is involved in NK cell – Aspergillus fumigatus interplay. We suggest that further investigation of these striking findings might offer a potent immunotherapeutic tool against IA. Disclosures No relevant conflicts of interest to declare.

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Glucose Oligosaccharide and Long-Chain Glucomannan Feed Additives Induce Enhanced Activation of Intraepithelial NK Cells and Relative Abundance of Commensal Lactic Acid Bacteria in Broiler Chickens

Veterinary Sciences ◽

10.3390/vetsci8060110 ◽

2021 ◽

Vol 8 (6) ◽

pp. 110

Author(s):

Nathalie Meijerink ◽

Jean E. de Oliveira ◽

Daphne A. van Haarlem ◽

Guilherme Hosotani ◽

David M. Lamot ◽

...

Keyword(s):

Immune System ◽

Nk Cells ◽

Relative Abundance ◽

Nk Cell ◽

Feed Additives ◽

Microbiota Composition ◽

In Ovo ◽

Long Chain

Restrictions on the use of antibiotics in the poultry industry stimulate the development of alternative nutritional solutions to maintain or improve poultry health. This requires more insight in the modulatory effects of feed additives on the immune system and microbiota composition. Compounds known to influence the innate immune system and microbiota composition were selected and screened in vitro, in ovo, and in vivo. Among all compounds, 57 enhanced NK cell activation, 56 increased phagocytosis, and 22 increased NO production of the macrophage cell line HD11 in vitro. Based on these results, availability and regulatory status, six compounds were selected for further analysis. None of these compounds showed negative effects on growth, hatchability, and feed conversion in in ovo and in vivo studies. Based on the most interesting numerical results and highest future potential feasibility, two compounds were analyzed further. Administration of glucose oligosaccharide and long-chain glucomannan in vivo both enhanced activation of intraepithelial NK cells and led to increased relative abundance of lactic acid bacteria (LAB) amongst ileum and ceca microbiota after seven days of supplementation. Positive correlations between NK cell subsets and activation, and relative abundance of LAB suggest the involvement of microbiota in the modulation of the function of intraepithelial NK cells. This study identifies glucose oligosaccharide and long-chain glucomannan supplementation as effective nutritional strategies to modulate the intestinal microbiota composition and strengthen the intraepithelial innate immune system.

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