scholarly journals A Novel Method to Study the in Vivo Trafficking and Homing of Adoptively Transferred NK Cells in Rhesus Macaques and Humans

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 659-659 ◽  
Author(s):  
Jan Davidson-Moncada ◽  
Noriko Sato ◽  
Robert F Hoyt ◽  
Robert N Reger ◽  
Marvin Thomas ◽  
...  

Abstract Adoptive transfer of allogeneic or autologous natural killer (NK) cells is now being developed for therapy of both hematological and solid malignancies. The efficacy of NK immunotherapy to mediate anti-tumor effects will ultimately be dependent on their ability to traffic and home to the tumor microenvironment. Recent data suggest expanded NK cells are ineffective at homing to the bone marrow (BM) and lymph nodes (LN) where hematological malignancies reside. A variety of techniques to maintain and/or enforce expression of homing receptors in NK cells are now being explored in preclinical models to improve their localization to the BM and LN. Historically, xenogeneic human into mouse or mouse into mouse models have been utilized for preclinical development of adoptive NK transfer. These experiments often use fluorescent dye-labeled NK cells and require repeated invasive biopsies, which can be confounded by sampling error, or the requirement for post mortem analysis. Here we present a method to track in real time and in vivo adoptively infused zirconium-89 (89Zr) labelled NK cells by PET imaging. A rhesus macaque (RM) model was used for these preclinical experiments as RM and human NK cells have similar expansion kinetics, and have greater similarity than mice in their phenotype, function, and homing receptors and ligands. PBMCs collected from the PB of 13 RMs were enriched for NK cells by CD3+ T-cell depletion and were then expanded for 14 days by culturing with irradiated human EBV-LCL cells in X-VIVO 20 media containing 10% human AB serum and 500 IU/μl of human IL-2. RM NK cells expanded a mean 145±41 fold and contained >99% pure CD3- and CD56+ cells. The phenotype and tumor cytotoxicity of RM NK cells were similar to NK cells expanded from humans (n=3) using similar expansion cultures; at a 10:1 E:T ratio, 67% and 73% of K562 cells were lysed by RM and human NK cell respectively. To label NK cells, 89Zr was conjugated to oxine, which readily permeabilized the cellular membrane and was retained in the cells. Expanded NK cells from both humans and RM showed no changes in CD16 or CD56 expression for up to 6 days following radiolabeling. Human and RM NK cell viability 0 to 24 hours following radiolabelling was 60-100% then declined to 20-30% after 6 days. 89Zr retention by both human and RM NK cells was 75-80% in the first 24 hours of culture but gradually declined with time, decreasing to 20-30% after 7 days of culture. Culturing radiolabeled human NK cells for 24-36 hours with different cellular populations including Ramos and Raji cell lines and normal human PBMCs revealed no significant transfer of radioactivity (max 2% above baseline), establishing that 89Zr was not transferred from labeled to unlabeled cells. Oxine labeling did not alter the cytotoxicity of human or RM NK cells vs K562 cells compared to unlabeled controls. 89Zr-oxine labeling of expanded RM NK cells is currently being used to quantify NK cell trafficking and survival following adoptive transfer in autologous macaques. In these experiments, RM recipients of adoptively infused 89Zr labeled NK cells receive concurrent deferoxamine to chelate and then enhance renal excretion of any free 89Zr that is released from dead cells. In the experiments shown below, 13 x 107 autologous ex vivo expanded 89Zr-labeled RM NK cells were injected IV into a 5.7 kg RM and tracked by sequential PET/CT imaging for 7 days. Up to 1-hour post infusion, most NK cell activity was restricted to the lungs. By 4 hours, NK cells began to traffic from the lungs to the liver and spleen. By 2 days, NK cells were no longer detectable in the lungs and resided largely in the liver and spleen, where they remained for the remainder of the 7 day imaging period. During the entire observation period, little to no NK cell radioactivity was detected in the LN or BM. In conclusion, 89Zr oxine labelling of NK cells followed by PET/CT imaging represents a powerful tool to track the in vivo fate of adoptively transferred NK cells. The RM model presented here provides a method to evaluate and optimize various strategies aimed at altering the phenotype of NK cells, with the goal of improving their homing to the BM and LN where hematological cancers reside. These preclinical in vitro and in vivo data suggest this technology could be safely extended to humans and could be applied to other cellular populations besides NK cells. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1912-1912
Author(s):  
Susann Szmania ◽  
Natalia Lapteva ◽  
Tarun K. Garg ◽  
Joshuah D Lingo ◽  
Amy D Greenway ◽  
...  

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.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1117-1117 ◽  
Author(s):  
Maximillian Rosario ◽  
Rizwan Romee ◽  
Stephanie E Schneider ◽  
Jeffrey W Leong ◽  
Ryan P Sullivan ◽  
...  

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.


Blood ◽  
2012 ◽  
Vol 119 (19) ◽  
pp. 4349-4357 ◽  
Author(s):  
Fanny Guimont-Desrochers ◽  
Geneviève Boucher ◽  
Zhongjun Dong ◽  
Martine Dupuis ◽  
André Veillette ◽  
...  

Abstract The cell lineage origin of IFN-producing killer dendritic cells (IKDCs), which exhibit prominent antitumoral activity, has been subject to debate. Although IKDCs were first described as a cell type exhibiting both plasmacytoid DC and natural killer (NK) cell properties, the current view reflects that IKDCs merely represent activated NK cells expressing B220, which were thus renamed B220+ NK cells. Herein, we further investigate the lineage relation of B220+ NK cells with regard to other NK-cell subsets. We surprisingly find that, after adoptive transfer, B220− NK cells did not acquire B220 expression, even in the presence of potent activating stimuli. These findings strongly argue against the concept that B220+ NK cells are activated NK cells. Moreover, we unequivocally show that B220+ NK cells are highly proliferative and differentiate into mature NK cells after in vivo adoptive transfer. Additional phenotypic, functional, and transcriptional characterizations further define B220+ NK cells as immediate precursors to mature NK cells. The characterization of these novel attributes to B220+ NK cells will guide the identification of their ortholog in humans, contributing to the design of potent cancer immunotherapies.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3928-3928
Author(s):  
Michele Levin ◽  
Janet Ayello ◽  
Frances Zhao ◽  
Andrew Stier ◽  
Lauren Tiffen ◽  
...  

Abstract Abstract 3928 Background: NK cells play a role in reducing relapse in hematological malignancy following AlloSCT (Dunbar et al, Haematologica, 2008). NK cell limitations include lack of tumor recognition and/or limited numbers of viable and functional NK cells (Shereck/Cairo et al, Ped Bld Can, 2007). NK ACI provide safe and effective therapy against tumor relapse; yet NK cells are limited to specific cancer types and not all patients demonstrate optimal response (Ruggieri et al. Science, 2002; Ljunggren et al. Nat Rev Immuno, 2007). To circumvent these limitations, methods to expand and activate PBMNCs with genetically engineered K562 cells expressing membrane bound IL-15 and 41BB ligand (K562-mbIL15-41BBL [modK562]; Imai/Campana et al, Blood, 2005) have shown to significantly increase NK cells in number and maintain heterogeneous KIR expression (Fusaki/Campana et al BJH, 2009). We have shown that CB NK cells can be activated/expanded and exhibit enhanced cytolytic activity when cultured in a cytokines/antibody cocktail (Ayello/Cairo et al, BBMT, 2006; Exp Heme, 2009). Objective: To evaluate CBNK expansion, activation, cytolytic mechanism and function against Burkitt lymphoma (BL) tumor target and its influence on NK cell mediated in-vitro and in-vivo cytotoxicity in NOD-SCID mice following stimulation with modK562 cells (generously supplied by D.Campana, St Jude's Children's Hospital, Memphis, Tx). Methods: Following 100GY irradiation, modK562cells were incubated 1:1 with CBMNCs in RPMI+IL-2 (10IU/ml) for 7 days in 5%CO2, 37°C. NK activation marker (LAMP-1), perforin and granzyme B were determined by flow cytometry. Cytotoxicty was determined via europium assay at 20:1 E:T ratio with Ramos (BL) tumor targets (ATCC). The mammalian expression construct (ffLucZeo-pcDNA (generously supplied by L.Cooper, MD, PhD) was transfected to BL cells using lipofectin and selected by zeocin for stable transfection. Six week old NOD-SCID mice received 5×106 BL cells subcutaneously. Upon engraftment, xenografted NOD-SCID mice were divided in 5 groups: injected with PBS (control), BL only, 5×106 wildtype (WT) K562 expanded (E) CBNK cells, modK562 expanded (E) CB NK cells (5×106) and modK562 expanded (E) CBNK cells (5×107). Ex-vivo ECBNK cells were injected weekly for 5 weeks and xenografted NOD-SCID mice were monitored by volumetric measurement of tumor size (Tomayko/Reynolds, Can Chemother Pharmac, 1989), bioluminescent imaging (Inoue et al Exp Heme, 2007) and survival. The survival distribution for each group was estimated using the Fisher exact test. Results: On Day 0, NK cells (CD56+/3-) population was 3.9±1.3%. After 7 days, modK562 expanded CBNK cells was significantly increased compared to WTK562 and media alone (72±3.9 vs 43±5.9 vs 9±2.4%, p<0.01). This represented a 35-fold or 3374±385% increase of the input NK cell number. This was significantly increased compared to WTK562 (1771±300%, p<0.05). ModK562 ECBNK cells demonstrated increased perforin and granzyme B expression compared to WTK562 (42±1.5 vs 15±0.5%,p<0.001; 22±0.5 vs 11±0.3%,p<0.001, respectively). Cytotoxicity was against BL tumor targets was significantly increased (42±3 vs 18±2%,p<0.01), along with NK activation marker expression, CD107a (p<0.05). At 5 weeks, in-vivo studies demonstrated increased survival of NOD-SCID mice receiving both 5×106 and 5×107 modK562 ECBNK cells when compared to those with no treatment (p=0.05, p=0.0007, respectively). There was no difference in survival when comparing mice that received 5×106 vs 5×107 modK562 ECBNK cells (p=0.0894) at 5 weeks. Tumor volume of mice receiving either dose of modK562 ECBNK cells was significantly less than those receiving WTK562 ECBNK cells (1.92±0.57 and 0.37±0.05 vs 3.41±0.25, p=0.0096 and p=0.0001, respectively). Conclusions: CBMNCs stimulated and expanded with modK562 cells results in significant expansion of CBNK cells with enhanced in-vitro cytotoxicity, significant receptor expression of NK activation marker (LAMP-1), and perforin and granzyme B. Furthermore, modK562 ECBNK cells leads to increased survival and lower tumor burden of NOD-SCID mice xenografted with BL. Future directions include modK562 ECBNK cells to be genetically modified to express chimeric antigen receptor CD20 (MSCV-antiCD20-41BB-CD3 ζ) against CD20+ hematologic malignancies for future studies to evaluate whether targeting enhances in-vitro and in-vivo cytotoxicity. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 355-355 ◽  
Author(s):  
Sarah Cooley ◽  
Bree Foley ◽  
Michael R Verneris ◽  
David McKenna ◽  
Xianghua Luo ◽  
...  

Abstract Abstract 355FN2 We have previously shown that adoptive transfer of haploidentical natural killer (NK) cells can induce remissions in patients with refractory or relapsed acute myeloid leukemia (AML). We hypothesize that in vivo expansion of functional NK cells is required for therapeutic efficacy. To achieve the adequate host immune suppression required for expansion we added total body irradiation (TBI) to our lymphodepleting chemotherapy regimen, giving patients fludarabine (Flu) 25 mg/m2 × 5 days, cyclophosphamide (Cy) 60 mg/kg × 2 days, and 400 cGy of TBI. The NK cell product, a CD3- and CD19-depleted lymphapheresis from a haploidentical related donor, was incubated overnight in 1000 U/ml IL-2 and infused followed by 6 doses of alternate day subcutaneous IL-2 (10 million units) to promote in vivo expansion. Because of the increased myelosuppression following the TBI, a CD34-selected filgrastim-mobilized peripheral blood graft from the same donor (target dose >3 × 106 CD34 cells/kg) was given for hematopoietic rescue. Successful in vivo NK cell expansion was prospectively defined as >100 donor-derived NK cells/ml at 14 days after adoptive transfer (by analysis of STR chimerism, % NK and the clinical absolute lymphocyte count). In the 38 evaluable patients, robust in vivo expansion was induced in 50% (absolute donor NK count of 666 ± 134 cells/μL blood), a rate considerably higher than the 10% we observed in a cohort receiving Cy/Flu alone without TBI. Successful NK cell expansion correlated with leukemia clearance (<1% marrow blasts 14 days after NK cell infusion) and remission (leukemia free with donor neutrophil engraftment at day +30; 42 days after NK infusion). Of the 19 patients who achieved NK cell expansion, 89% cleared their leukemia compared to 42% of the non-expanders (p=0.002); and 84% achieved remission vs. 10% of non-expanders (p <.0001). The robust in vivo expansion of adoptively transferred NK cells gave us the unique opportunity to study their function. We studied blood collected from patients 14 days after NK cell infusion and compared it to paired donor samples obtained at steady state from the apheresis products prior to IL-2 stimulation. Using multi-color flow cytometry, we measured CD107a expression (a surrogate marker for NK cell cytotoxicity) on NK cells which we could subset by expression of single inhibitory killer cell immunoglobulin-like receptors (KIR) (CD158a, CD158b and CD158e) or NKG2A. We defined NK subsets as self-KIR+ or non-self KIR+ based on the cognate HLA ligands (C2, C1, Bw4) present in the donor or recipient. The bulk population of in vivo expanded donor NK cells exhibited hyperfunction with 62.4±4.4% degranulation in response to class I negative K562 targets compared to 36.6±3.0% in the donor product samples (N=15; p=0.0043). As expected, the most potent NK cells in the unstimulated donor product were the self-KIR+ subset, which expressed 39.5±3.0% CD107a after incubation with K562 (N=23) compared to either the non-self KIR+subset (13.1±4.0%, N=6; p=0.0001), or the uneducated KIR−/NKG2A− subset (12.4±5.8%, N=10; p<0.0001). Remarkably, all 3 subsets exhibited even greater degranulation activity after 14 days of in vivo expansion where they were exposed to homeostatic factors and the IL-2 administered to the patient. While all subsets expressed more CD107a, the rules of education were maintained. The subset expressing self-KIR that recognized donor HLA ligands degranulated significantly better than the non-self KIR+ subset (53.5±14.1% vs. 34.3±13.6%, p<0.01). Interestingly, the in vivo expanded NK cells with KIR recognizing cognate ligands unique to the recipient also functioned better (53.1±14.3% [recipient self KIR+] vs. 32.4±12.0% [non-self KIR+], N=25 and N=6; p<0.0045), showing that the education status of adult NK cells is dynamic, not fixed. Importantly, the KIR−/NKG2A− subset functioned better after in vivo expansion (39.5±115.3%, N=12), demonstrating that adoptively transferred NK cells can acquire function by two separate mechanisms: 1) acquisition of function through NK cell education; and 2) acquisition of function by homeostatic expansion and cytokine activation. These data suggest that while hyperfunctioning NK cells that expand in vivo after adoptive transfer partially overcome self tolerance, which may augment their anti-leukemic effects, they still follow the rules of NK cell education where self KIR+ cells kill better than non-self KIR+ cells. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4501-4501 ◽  
Author(s):  
Rizwan Romee ◽  
Jeffrey W Leong ◽  
Stephanie E Schneider ◽  
Ryan P Sullivan ◽  
Megan Cooper ◽  
...  

Background Allogeneic NK cells are anti-leukemia immune effector lymphocytes, with evidence of activity in patients in adoptive transfer clinical studies. What is the optimal approach to prepare allogeneic NK cells for maximal effector function remains an open question for adoptive NK cell therapy. Recently described cytokine-induced memory-like (CIML) NK cells are generated following a brief (16 hour) pre-activation with a combination of IL-12+IL-15+IL-18 in both mice and humans. Following weeks or months of rest, CIML NK cells exhibit an enhanced recall IFN-g response when restimulated with K562 cells or cytokines. However, their anti-leukemic cytotoxic activity and identification of key supporting cytokines for survival and sustained functionality have not been reported. We hypothesized that CIML NK cells may have enhanced effector function against AML, providing a potential rationale for future clinical studies of CIML NK cells in AML patients. To test this hypothesis we investigated the CIML NK cell response to myeloid leukemia, including primary AML blasts, and evaluated their function following transfer into NSG mice. Methods Normal human donor NK cells (>95% purity) were cultured with low dose (1 ng/mL) IL-15 alone (control) or pre-activated with IL-12 (10 ng/ml) + IL-15 (1 ng/ml) + IL-18 (50 ng/ml) for 16 hours. After washing, the cells were cultured for 7 days in low dose IL-15 (to support survival). Following this prolonged rest period in vitro, NK cell responses were assessed after 6-hour re-stimulation with K562 leukemia cells or primary AML blasts. NK cell functional responses assessed include IFN-g production and cytotoxicity (using flow based killing assays). For adoptive transfer experiments, 5-8 x 106 human CIML NK cells or control cells were injected into sub-lethally irradiated NSG mice, and assessed for persistence, expansion and function of the adoptively transferred CIML NK or control NK cell. Additional experiments included evaluating CIML NK cells for cytokine receptor expression and effector proteins after the 7 day rest period. Results As described previously, CIML NK cells had a significantly increased IFN-g response to K562 leukemia cells (15.5 ± 3% vs. 7 ± 1%, P=0.03). CIML NK cells also exhibited a more potent IFN-g response to primary blasts from untreated, newly diagnosed AML patients (N=4 AML samples, P< 0.0001). Further, CIML NK cells demonstrated a significantly greater cytotoxic response, compared to control NK cells, upon co-incubation with K562 leukemia cells (Figure 1). Consistent with this enhanced cytotoxicity, CIML NK cells had significantly increased expression of granzyme A (P=0.005) and granzyme B (P=0.006) proteins. Further, we noted a marked induction of CD25 (IL-2Ra) after IL-12+IL-15+IL-18 pre-activation, which via the IL-2Rabg resulted in enhanced functional responses to picomolar concentrations of IL-2. This included enhanced cytotoxicity against leukemia cells, IFN-g production in response to co-stimulation with IL-12, and proliferation. To assess persistence and expansion upon adoptive transfer, NSG mice were injected with control or CIML NK cells. After 7 days (during which 75,000IU of IL-2 was injected qOD) there was a preferential expansion of the CIML NK cells in blood (11±2.6 vs. 5±1.3, P=0.01) and bone marrow (0.6±0.14 vs. 0.21±0.06, P= 0.03) in these mice as assessed by the ratio of human to mouse CD45 positive cells. Further, CIML NK cells supported in vivo in NSG mice exhibited enhanced IFN-g responses upon re-stimulation with K562 leukemia cells (10±1.5% vs. 2.5±1% IFN-g positive, P= 0.03) or IL-12+IL-15 (15±2% vs. 2±0.5%, P= 0.001). Conclusions Brief (16 hour) pre-activation with a combination of IL-12+IL-15+IL-18 results in the generation of CIML NK cells that have an enhanced IFN-g and cytotoxic response to K562 leukemia cells and primary allogeneic AML blasts. Further, CD25 is induced on CIML NK cells, which in the context of the high affinity IL-2Rabg confers selective responsiveness to low concentrations of IL-2 for proliferation, enhanced cytotoxicity, and enhanced IFN-g production. CIML NK cells may develop in vivo in NSG xenografts, and CIML NK cells appear to be selectively supported by exogenous low dose IL-2 in this context. These pre-clinical data support CIML NK cells as a novel optimization approach for NK cell adoptive immunotherapy. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3825-3825
Author(s):  
Jennifer A. Foltz ◽  
Melissa M. Berrien-Elliott ◽  
David A. Russler-Germain ◽  
Carly C. Neal ◽  
Jennifer Tran ◽  
...  

Abstract Natural killer (NK) cells are innate lymphoid cells that mediate anti-tumor responses and exhibit innate memory following stimulation with IL-12, IL-15, and IL-18, thereby differentiating into cytokine-induced memory-like (ML) NK cells. ML NK cells have well-described enhanced anti-tumor properties; however, the molecular mechanisms underlying their enhanced functionality are not well-understood. Initial reports of allogeneic donor ML NK cellular therapy for relapsed/refractory (rel/ref) acute myeloid leukemia (AML) demonstrated safety and a 47% CR/CRi rate (PMID32826231). In this setting, allogeneic ML NK cells are rejected after 3 weeks by recipient T cells, which precludes long-term evaluation of their biology. To address this limitation, we conducted a clinical trial for rel/ref AML patients that added adoptive transfer of same-donor ML NK cells on day +7 of a reduced-intensity conditioning (RIC) MHC-haploidentical HCT, followed by 4 doses of IL-15 (N-803) over 2 weeks (NCT02782546). Since the ML NK cells are from the HCT donor, they are not rejected, but remain MHC-haploidentical to the patient leukemia. Using samples from these patients, we profiled the single cell transcriptomes of NK cells using multidimensional CITE-seq, combining scRNAseq with a custom NK panel of antibodies. To identify donor ML NK cells in an unbiased fashion, we developed a CITE-seq ML NK classifier from in vitro differentiated paired conventional NK (cNK) and ML NK cells. This classifier was applied via transfer learning to CITE-seq analyzed samples from the donor (cNK cells) and patients at days +28 and +60. This approach identified 28-40% of NK cells as ML at Day +28 post-HCT. Only 1-6% of donor peripheral blood NK cells and 4-7% of NK cells in comparator leukemia patients at day +28 after conventional haplo-HCT alone were identified as ML NK cells (Fig 1A). These ML NK cells had a cell surface receptor profile analogous to a previously reported mass cytometry phenotype. Within the CITE-seq data, ML NK cells expressed a transcriptional profile consistent with enhanced functionality (GZMK, GZMA, GNLY), secreted proteins (LTB, CKLF), a distinct adhesome, and evidence of prior activation (MHC Class II and interferon-inducible genes). ML NK cells had a unique NK receptor repertoire including increased KIR2DL4, KLRC1(NKG2A), CD300A, NCAM1(CD56) , and CD2 with decreased expression of the inhibitory receptor KLRB1(CD161). Furthermore, ML NK cells upregulated HOPX, a transcription factor implicated in memory T cells and murine CMV adaptive NK cells. Additionally, ML NK cells downregulated transcription factors related to terminal maturation (ZEB2) and exhaustion (NR4A2). We next sought to identify changes during ML differentiation in patients post-HCT from day +28 to +60 post-HCT. Trajectory analysis identified a ML NK cell state distinct from cNK cells that was present at least 60 days post-HCT (Fig 1B). The ML transcriptional phenotype continued to modulate during late differentiation, including downregulation of GZMK and NCAM1, and upregulation of maturation related transcription factors, while maintaining high expression of HOPX. ML NK cells retained their enhanced functionality during in vivo differentiation, as patient ML NK cells had significantly increased IFNγ production compared to cNK cells after restimulation with leukemia targets or cytokines using mass cytometry (Fig. 2). Subsequently, we confirmed the ML CITE-seq profile in an independent clinical trial treating pediatric AML relapsed after allogenic HCT with same-donor ML NK cells (NCT03068819). In this setting, ML NK cells expressed a similar transcriptional signature and persisted for at least 2 months in the absence of exogenous cytokine support. Thus, ML NK cells possess a distinct transcriptional and surface proteomic profile and undergo in vivo differentiation while persisting within patients for at least 2 months. These findings reveal novel and unique aspects of the ML NK cell molecular program, as well as their prolonged functional persistence in vivo in patients, assisting in future clinical trial design. Figure 1 Figure 1. Disclosures Foltz: Kiadis: Patents & Royalties: TGFbeta expanded NK cells; EMD Millipore: Other: canine antibody licensing fees. Berrien-Elliott: Wugen: Consultancy, Patents & Royalties: 017001-PRO1, Research Funding. Bednarski: Horizon Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Fehniger: Wugen: Consultancy, Current equity holder in publicly-traded company, Patents & Royalties: related to memory like NK cells, Research Funding; ImmunityBio: Research Funding; Kiadis: Other; Affimed: Research Funding; Compass Therapeutics: Research Funding; HCW Biologics: Research Funding; OrcaBio: Other; Indapta: Other.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2293-2293
Author(s):  
Ekta Kapadia ◽  
Elad Jacoby ◽  
Mark Kohler ◽  
Waleed Haso ◽  
Christopher Daniel Chien ◽  
...  

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.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3430-3430
Author(s):  
Sebastien Viel ◽  
Laurie Besson ◽  
Emily Charrier ◽  
Jacques Bienvenu ◽  
Emmanuel Disse ◽  
...  

Abstract The impact of adiposity on the immune system remains largely unexplored. While obesity has been suggested to be a predisposing or adverse prognostic factor in certain neoplastic diseases it is not yet clear to what extent this may involve the innate or adaptative immune systems. Adipose tissue produces a large number of secreted molecules, or adipocytokines, which may have immunomodulatory functions. This project aimed to determine whether phenotypical and/or functional properties of circulating natural killer (NK) cells were influenced by body mass index (BMI). In a preliminary study, 47 patients with no history of hematological malignancy were included, including 14 healthy volunteers with a normal BMI (18.5-25), 10 patients considered to be overweight (25 < BMI < 30), 11 patients considered as obese (BMI > 30) and 12 patients who were previously obese and had lost weight. Peripheral blood was analyzed by flow cytometry for the following markers: activating receptors (CD16, C161, DNAM-1, 2B4, NKG2C, NKG2D, NKp46, NKp30), inhibitor receptors (NKG2A, KIR2DL1, KIR2DL2, KIR3DL1), activation markers (CD69, granzyme B, NKG2C), maturation markers (CD56, CD57, CD94, CX3CR1) and cytotoxicity markers (perforin, NKG7). Moreover the capacity of NK cells to degranulate and to produce several cytokines (TNF, IFN-g) or chemokines (MIP1-b) in response to stimulation by K562 cells or Rituximab coated -tumor B cells was evaluated. Results showed a positive correlation between BMI and total number of circulating NK cells, with a significant difference between lean patients and obese patients. Immunophenotypic analyses showed that NKp46 and CD94 expression (measured by Mean Fluorescence Intensity) were both significantly reduced with increased BMI. NK cells from obese patients also show signs of activation, characterized by an elevation of the expression of CD69 and granzyme B and a reduction of the expression of CD16. The ability of NK cells to be activated in the presence of cell lines was also reduced in obese patients: NK cell secretion of IFN-g and MIP-1b in the presence of Granta cells or MIP-1b in the presence of K562 decreased linearly with increasing BMI. NK cell degranulation upon co-culture with K562 cells was also negatively correlated with BMI. In these different assays pre-obese and ex-obese patients scored intermediate between lean and obese patients. Overall these results suggest in vivo activation and exhaustion of NK cells in obese patients. These cells are thus potentially less likely to participate as effector cells in immunotherapeutic regimens. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4244-4244 ◽  
Author(s):  
Elena Cherkasova ◽  
Luis Espinoza ◽  
Ritesh Kotecha ◽  
Robert N. Reger ◽  
Maria Berg ◽  
...  

Abstract Daratumumab is a fully humanized monoclonal antibody (IgG1) that targets CD38 expressed on myeloma cells. Daratumumab kills myeloma cells through antibody dependent cellular toxicity (ADCC), compliment dependent cytotoxicity (CDC), and antibody dependent phagocytosis (ADCP). In early clinical trials, daratumumab has showed significant anti-myeloma activity in patients with treatment refractory disease. In vivo, daratumumab has been found to induce NK cell lymphopenia of unclear etiology. We found that NK cells isolated from the peripheral blood of healthy and cancer patients expressed variable surface levels of CD38 (Fig. 1A). Further, surface expression of CD38 increased substantially when NK cells underwent ex vivo cytokine activation by culturing cells overnight in IL-2 containing media or ex vivo expansion using irradiated EBV-LCL feeder cells (Fig. 1B). Remarkably, daratumumab induced apoptosis of expanded NK cells in a dose dependent manner, with substantial NK cell apoptosis occurring within 2 hours following in vitro exposure to daratumumab at a concentration of 1 and 10 ug/ml (Fig. 1C). Further, adoptive transfer of ex vivo expanded human NK cells into NSG mice that had been pre-treated with daratumumab showed daratumumab induced NK cell killing in vivo: the numbers of NK cells isolated from the lungs, blood, spleen and bone marrow of NSG mice 24 hours after infusion of expanded human NK cells was reduced by 90% in mice that were pretreated with 1 mg/kg of daratumumab i.p. compared to controls that had not received the antibody (Fig. 1D). In vitro experiments showed NK cell killing by daratumumab occurred as a consequence of ADCC and was dependent on NK cell CD16 expression; when CD56+ NK cells were sorted by FACS into CD16 positive and negative populations, only NK cells expressing CD16 were killed by daratumumab, with no effect on NK cell viability occurring in the CD16- NK cell. Further, we observed that NK cells obtained from donors who have high affinity FCgR3 as a consequence of a single nucleotide polymorphism in the FCGR3A gene resulting in an amino acid substitution at position 158 (F158V) in CD16 were more sensitive to daratumumab killing compared to NK cells isolated from donors carrying the low affinity CD16 polymorphism. Although NK cell counts and NK reduction in peripheral blood and bone marrow were not associated with daratumumab clinical response in myeloma studies, NK cells play an important role in mediating antitumor responses through ADCC following mAb therapy. In this regard, combining mAb therapy with adoptive transfer of ex vivo expanded NK cells could be utilized as a strategy to potentiate the antitumor effects of mAbs. To overcome daratumumab-mediated killing of adoptively transferred NK cells in daratumumab-treated patients, we blocked CD38 on the surface of NK cells by pretreating them with daratumumab F(ab')2 fragments. The F(ab')2 fragments that were generated using pepsin cleavage of daratumumab were confirmed to bind and block the CD38 epitope expressed on NK cells. Importantly, these F(ab')2 fragments remained bound to the surface of NK cells for at least 96 hours, did not induce NK cell apoptosis, protected NK cells from daratumumab-mediated NK cell killing, and bolstered their tumor cytotoxicity against daratumumab-treated myeloma targets. In vitro experiments showed NK cell tumor cytotoxicity vs myeloma cells in daratumumab-containing media was significantly higher by NK cells that had CD38 blocked with F(ab')2 fragments compared to unblocked controls (Fig. 1E). Importantly, pretreatment with daratumumab F(ab')2 fragments also protected human NK cells from daratumumab-mediated killing in vivo; expanded NK cells pretreated with F(ab')2 fragments prior to adoptive transfer into NSG mice that had been treated with daratumumab were detectable at significantly higher numbers in the blood compared to untreated NK cell controls (Fig. 1F). Conclusion: Expression of CD38 on activated NK cells makes them susceptible to killing by daratumumab, which could compromise the ability of adoptively transferred NK cells to bolster ADCC following treatment with this mAb. Pretreatment of ex vivo expanded NK cells with daratumumab F(ab')2 fragments protects cells from daratumumab-mediated killing, potentially offering a strategy to augment the anti-tumor effects of adoptively transferred NK cells in myeloma patients that have received daratumumab treatment. Disclosures No relevant conflicts of interest to declare.


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