scholarly journals Full Spectrum Flow Cytometry for High-Dimensional Immunophenotyping of Murine Innate Lymphoid Cells

2022 ◽  
Author(s):  
Kyle T Mincham ◽  
Robert J Snelgrove

This 25-parameter, 22-colour full spectrum flow cytometry panel was designed and optimised for the comprehensive enumeration and functional characterisation of innate lymphoid cell (ILC) subsets in murine tissues (Table 1). The panel presented here allows the discrimination of ILC progenitors (ILCP), ILC1, ILC2, NCR+ ILC3, NCR- ILC3, CCR6+ ILC3 and mature natural killer (NK) cell populations. Further characterisation of ILC and NK cell functional profiles in response to stimulation is provided by the inclusion of subset-specific cytokine markers, and proliferation markers. Development and optimisation of this panel was performed on freshly isolated cells from adult BALB/c lungs and small intestine lamina propria, and ex vivo stimulation with phorbol 12-myrisate 13-acetate, ionomycin, brefeldin A and pro-ILC activating cytokines.

2017 ◽  
Author(s):  
Yetao Wang ◽  
Kyle Gellatly ◽  
Sean McCauley ◽  
Pranitha Vangala ◽  
Kyusik Kim ◽  
...  

HIV-1-infected people who take medications that suppress viremia, preserve CD4+ T cells, and prevent AIDS, have chronic inflammation with increased cardiovascular mortality. To investigate the etiology of this inflammation, the effect of HIV-1 on innate lymphoid cells (ILCs) and NK cells was examined. Homeostatic ILCs in blood and intestine were depleted permanently. NK cells were skewed towards a memory subset. Cytokines that are elevated during HIV-1 infection reproduced both abnormalities ex vivo. Pseudotime analysis of single NK cell transcriptomes revealed a developmental trajectory towards a subset with expression profile, chromatin state, and biological function like memory T lymphocytes. Expression of TCF7, a WNT transcription factor, increased over the course of the trajectory. TCF7 disruption, or WNT inhibition, prevented memory NK cell induction by inflammatory cytokines. These results demonstrate that inflammatory cytokines associated with HIV-1 infection irreversibly disrupt homeostatic ILCs and cause developmental shift towards TCF7+ memory NK cells.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3090-3090 ◽  
Author(s):  
Folashade Otegbeye ◽  
Nathan Mackowski ◽  
Evelyn Ojo ◽  
Marcos De Lima ◽  
David N. Wald

Abstract Introduction: A crucial component of the innate immune response system, natural killer (NK) cells are uniquely competent to mediate anti-myeloid leukemia responses. NKG2D is an activating receptor on the surface of NK cells that engages stress ligands MICA and MICB, typically upregulated on myeloid leukemia cells. Adoptive transfer of NK cells is a promising treatment strategy for AML. Strategies to optimize the anti-leukemia effect of NK cell adoptive transfer are an area of active research. These include attempts to enhance NK cell activity and to maintain the activation status and proliferation of the NK cells in vivo. Traditionally, IL-2 has been used to maintain the in vivo proliferation of adoptively transferred NK cells, but it leads to unwanted proliferation of regulatory T cells and suboptimal NK cell proliferation. IL-15 may be superior to IL-2, without the effects on T regulatory cells. The IL-15 superagonist, ALT-803 exhibits >25 fold enhancement in biological activity as compared to IL-15. ALT-803 is a fusion protein of an IL-15 mutant and the IL-15Rα/Fc complex that has recently entered clinical trials as a direct immunomodulatory agent in cancer clinical trials We hypothesized ALT-803 would augment the activity and/or proliferation of adoptively transferred NK cells in vitro and in a mouse model system.. Methods: Human NK cells were isolated from healthy donor peripheral blood and were expanded over a 21-day period in co-culture with irradiated K562 cells genetically modified to express membrane-bound IL-21. (Somanchi et al. 2011 JoVE 48. doi: 10.3791/2540) The NK cells were expanded with IL-2 (50mU/mL) and/or ALT-803 (200ng/mL). On Day 21, NK cells were examined for cytotoxicity against AML cells as well as by flow cytometry for expression of known activating receptors. An NSG murine xenograft model of human AML was developed to test the in vivo function of NK cells expanded above. Briefly, NSG mice (n=5 per group) were non-lethally irradiated and each injected IV with 5 x106 OCI-AML3 leukemic cells. Two days later, each mouse received weekly NK cell infusions for 2 weeks. Mice that received NK cells expanded with IL2 got cytokine support with IL-2 (75kU IP three times a week). Mice infused with ALT-803 expanded cells (alone or in combination with IL2) received ALT-803 (0.2mg/kg IV weekly). One control group received OCI cells but were infused weekly only with 2% FBS vehicle, no NK cells. Leukemic burden in each mouse was assessed by flow cytometry of bone marrow aspirates on day 28 following start of NK cell infusions). This time point was chosen as the control mice appeared moribund. Results: ALT-803 did not have any differential effect on the proliferation of the NK cells ex vivo as compared to IL-2. However, the presence of ALT-803 either alone or in combination with IL-2 resulted in a significant increase (30% increase, p<0.0001) in the cytotoxic activity of the NK cells against leukemia cells as compared with IL-2 alone in vitro (figure 1). In addition, the percentages of NK cells that express the activating receptor NKG2D as well as CD16 were significantly higher (p<0.001 for both) after ALT-803 exposure (figure 1). Finally, in the murine xenograft AML model, ALT-803 expanded NK cells, which were also supported in vivo with ALT-803, resulted in an 8-fold reduction in disease burden in the bone marrow (p<0.0001). Importantly the efficacy of NK cells in the ALT-803 injected mice was significantly higher (3-fold, p= 0.0447) than IL-2 treated mice (figure 2). Discussion: Our results suggest that the presence of ALT-803 during ex-vivo expansion of NK cells results in increased activation and cytotoxicity against AML cells. In addition our results using a murine model of human AML show that the use of ALT-803 in combination with adoptively transferred NK cells provides a significant anti-leukemic benefit as compared to IL-2. Future studies to test larger panels of leukemia cells as well as other cancer cell lines are currently in progress. It is hoped that this work will lead to an improvement in the efficacy of adoptively transferred NK cells for AML patients due to an improvement in survival and activity of the NK cells. Disclosures Wald: Invenio Therapeutics: Equity Ownership.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2916-2916
Author(s):  
Jan Spanholtz ◽  
T. M. de Witte ◽  
Marleen Tordoir ◽  
Harry Dolstra

Abstract Alloreactive donor Natural Killer (NK) cells, displaying a KIR-ligand mismatch with the recipient play a pivotal role in graft-versus-leukemia (GVL) reactivity without significant graft-versus-host disease (GVHD) following haploidentical stem cell transplantation. Therefore, infusions of haploidentical NK cells are suggested to become an attractive approach for cancer immunotherapy. So far, difficulties in isolation and expansion of peripheral NK cells resulted in only limited data about safety and clinical efficacy of purified NK cell infusions. Therefore, we have developed a novel culture system without the use of feeder cells for the ex vivo generation of NK cells from CD34+ hematopoietic progenitor cells (HPCs) isolated from cord blood (CB) or bone marrow (BM). It is based on a two-step procedure using an expansion and a differentiation step. The NK cell generation system uses mainly cytokines such as SCF, TPO, Flt3-L, IL-2, IL-7 and IL-15 and specific modified glycosaminoglycans (GAGs) to direct and control the two phases. The developmental phase and the final NK cell product is controlled and characterized by immunophenotyping using multi-colour flow cytometry and CFSE-based cytotoxicity assays against various tumor cells. Our system generates a homogeneous final cell product of CD56+/CD3- cells with a purity of &gt;99%. A total cell expansion of more than 5×10^4 fold allows to generate 5×10^10 NK cells from 1×10^6 CB CD34+ stem and progenitor cells within 4–5 weeks of culture. For BM cells an expansion rate of more than 1×10^4 fold was detected after a 5–6 week cell culture period. During the two week expansion phase step,we expand UCB CD34+ cells more than 100 fold. Phenotypic analysis showed a decrease of stem cell-specific antigens such as CD34 and CD117 during the first three weeks, whereas antigens specific for NK cell progenitors and mature NK cells such as CD56, CD94 and CD161 are up-regulated after initiating differentiation at day 14. Furthermore, distinct cell populations can be detected reflecting NK cell developmental stages in vitro. Effective differentiation of the expanded progenitor cells into mature NK cells is characterized by the expression of NK cell-specific antigens including CD56, CD94, NKG2A, NKG2D and NCRs as well as homing receptors such as CD62L, CXCR4 and CCR7. The final NK cell product shows high expression levels of inhibitory and activating receptors as well the intrinsic capability to express KIR, which is detected by flow cytometry after 6–7 weeks of culture. Cytotoxicity assays demonstrated robust lysis of more than 90% against AML as well as melanoma tumor cell lines. This system, with its huge expansion potential to generate highly activated NK cells with homing capability, is the basis for a first clinical trial in 2009, to infuse haploidentical NK cells generated from CD34+ cells in poor-risk AML patients. The use of our defined culture conditions enables new prospects in NK cell research, regarding NK cell development and NK cell maturation, as well as new aspects for the clinical use of NK cell products derived from HPCs.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4499-4499 ◽  
Author(s):  
Toshihiro Onishi ◽  
Maria Berg ◽  
Robert Reger ◽  
Leonard Miller ◽  
Steve Wolpe ◽  
...  

Introduction The ability of adoptively infused NK cells to home and traffic to the microenvironment where the tumor resides may be a critical determinant of their ability to mediate clinically meaningful anti-tumor effects. The initial step in leukocyte emigration from post-capillary venules, referred to as “tethering”, is a low-affinity interaction between leukocyte ligands with selectins expressed on endothelial cells. Since E-selectin is constitutively expressed on endothelium of skin and bone marrow in humans, leukocyte recruitment to bone marrow is thought to be largely dependent on E-selectin-binding. Among E-selectin ligands, only ligands bearing sialyl Lewis X with a terminal fucose (fucosylated) are functional forms that actively bind to E-selectin. One of the pitfalls of ex vivo NK cell expansion for adoptive infusion in humans is that expanded NK cells express predominantly non-fucosylated E-selectin ligands. We hypothesized that ex vivo fucosylation could enhance the binding capacity of E-selectin ligands on NK cells improving their homing into bone marrow where hematological malignancies reside. Methods CD56+/CD3- NK cells were isolated from normal human subjects by immuno-magnetic bead selection and were expanded ex vivo over 7-21 days by co-culturing with irradiated EBV-LCL feeder cells in IL-2 containing medium. Expanded NK cells were incubated for 30 minutes at room temperature with GDP-fucose and alpha1,3 fucosyltransferase-VI (ASC-101). The levels of fucosylation were determined by CLA surface expression measured by flow cytometry using the antibody HECA-452. After fucosylation, NK cells were analyzed by flow cytometry to assess for phenotype changes, viability and stability of fucosylation. Chromium release assays were performed to assess NK cell cytotoxicity against tumor cells. To determine whether fucosylated NK cells had enhanced binding to E-selectin, the binding capacity of NK cells to human recombinant E-selectin/Fc Chimera protein was evaluated by flow cytometry. Results Expanded human NK cells had low levels of baseline fucosylation, ranging from only 10-25%. Expanded NK cells were successfully fucosylated with ASC-101 in a dose-dependent manner (figure); the MFI of CLA on NK cells peaked at 25 ug/ml of ASC-101, with nearly 100% of NK cells being fucosylated (CLA positive). Fucosylation did not affect NK cell viability nor was it associated with changes in NK cell phenotype including surface expression of CD16, CD56, KIR2DL1, KIR2DL2/3, KIR3DL1, NKG2A, NKG2D, TRAIL, perforin, or granzymes A/B. Ex vivo cell culture showed fucosylation was sustained at nearly 100% for 48 hours, but then rapidly declined returning to baseline levels by 96 hours. NK cell cytotoxicity against tumor targets including K562 cells and myeloma cells was preserved and unaffected by fucosylation. Fucosylation significantly enhanced the binding capacity of NK cells to human E-selectin. Further, NK cell binding to recombinant human E-selectin/Fc chimera protein directly correlated with the degree of NK cell fucosylation (figure), which was dose-dependent on the ASC-101 concentration. The effects of forced fucosylation on the ability of human NK cells to home to the bone marrow following adoptive transfer into immuno-deficient mice is currently being explored. Conclusion Expanded NK cells primarily express non-glycosylated ligands for E-selectin, potentially limiting their ability to home to the bone marrow following adoptive transfer in humans with hematological malignancies. Ligands for E-selectin on the surface of expanded NK cells can be glycosylated ex vivo rapidly and to high degrees using ASC-101, significantly enhancing their ability to bind E-selectin. These data suggest forced fucosylation of NK cells could be used as a novel approach to improve the antitumor effects of adoptive NK cell infusions in patients with hematological malignancies. Disclosures: Miller: America Stem Cell Inc: Employment. Wolpe:American Stem Cell, Inc: Employment. Koh:America Stem Cell Inc: Employment.


2021 ◽  
Vol 2 (1) ◽  
pp. 100262
Author(s):  
Pamela Wong ◽  
Julia A. Wagner ◽  
Melissa M. Berrien-Elliott ◽  
Timothy Schappe ◽  
Todd A. Fehniger

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 869-869 ◽  
Author(s):  
Melissa M Berrien-Elliott ◽  
Margery Gang ◽  
Nancy M Marin Agudelo ◽  
Lynne M Marsala ◽  
Mark Foster ◽  
...  

NK cells are cytotoxic innate lymphoid cells that mediate anti-tumor responses and traffic to most tissues. NK cells activated briefly with IL-12, IL-15, and IL-18 differentiate into memory-like (ML) NK cells with enhanced anti-tumor effects, which has been translated into clinical trials for patients with leukemia. Adoptive cellular therapy with donor ML NK cells were safe and induced CR/CRi in &gt;50% of rel/ref AML patients in a first-in-human phase 1 clinical trial at Washington University (PMID27655849). In preliminary results, donor ML NK cells expand and can persist for months in an immune-compatible recipients during or after allogeneic hematopoietic cell transplantation (HCT), and maintain potent effector function. However, NK cell recognition of many cancer types is limited, since they depend on expression of stress-induced activating receptor ligands. We hypothesized that ML NK cells engineered with chimeric antigen receptors (CAR) would demonstrate improved anti-tumor responses against classically NK-resistant targets. To test this idea, ML NK cells were engineered to express an anti-CD19-CAR, and responses against NK-resistant B-cell malignancies evaluated in vitro and in vivo. CAR-modified primary human ML NK cells (CAR-ML) were transduced with an anti-CD19-CD8a-41BB-CD3z-GFP (CD19-CAR-ML) lentivirus. This differentiation and transfection approach resulted in approximately 15-25% of ML NK cells transduced with the CAR construct, as determined flow cytometry staining for soluble CD19 and GFP. As an additional control, αCD33-CD8a-41BB-CD3z-GFP CAR-transduced ML NK cells and GFP- internal control ML NK cells were used. Here, in vitro functional assays were used to determine if CD19-CAR enhances ML NK cells in an antigen (CD19)-specific manner. CD19-CAR-ML (GFP+) and control ML NK (GFP-) cells were evaluated for functional responses to CD19-positive or CD19-negative tumor targets in vitro. CD19-CAR-ML NK cells demonstrated significantly increased IFN-γ production (44±4% vs. 15±3%, p&lt;0.001); mean ± SEM) and degranulation (31±4% vs. 5±1%, p&lt;0.001) against NK-resistant CD19+ Raji targets, compared to control GFP- and CD33-CAR ML NK cells. To understand the contributions of ML differentiation on the enhanced functionality of CD19-CAR modified NK cells, we compared CD19-CAR-ML NK cells to control CD19-CAR NK cells that were treated with IL-15 only. CD19-CAR-ML NK cells also exhibited significantly increased effector responses compared to control CAR NK cells against CD19+ targets (p&lt;0.01). CD19-CAR-ML NK cells responded similarly to GFP- ML NK cells against CD19-negative Kasumi leukemia targets. Finally, CD19-CAR-ML NK cells also exhibited significantly enhanced killing, degranulation, and IFN-γ production against primary CD19+ follicular lymphoma targets from patient lymph nodes (p&lt;0.01). To establish the translational utility of this approach, autologous CD19-CAR-ML NK cells generated from lymphoma patients demonstrated significantly increased IFN-γ production (p&lt;0.05) and degranulation (p&lt;0.01) against their own CD19+ lymphoma targets, compared to control ML NK cells (GFP-). These data confirm contributions of both ML differentiation and CAR expression in the enhanced antigen-specific, anti-tumor responses observed in CAR-ML NK cells. To test the expansion and persistence of ML NK cells transduced with CD19 or CD33-CAR were transferred into CD19+ Raji-bearing NSG mice and supported in vivo with IL-15. After three weeks, mice were sacrificed and NK (CD56) cell persistence and tumor (CD19) burden assessed by flow cytometry. CD19-CAR ML recipient mice had reduced tumor burden in the BM, spleen, and blood compared to CD33-CAR ML treated mice. Notably, CD19-CAR-ML (GFP+) were increased to &gt;70% of human NK cells from 20% in the CD33-CAR-ML recipient mice, suggesting antigen-specific CAR-expressing NK cells expand or survive better in vivo than non-transduced ML or non-specific CAR-ML NK cells in vivo. Thus, combining CAR with ML differentiation results in NK cells with enhanced responses to NK resistant tumors. These studies warrant continued CAR-ML development and provide the pre-clinical rationale for translating this combination NK cell therapy approach to the clinic. Figure Disclosures Fehniger: Cyto-Sen Therapeutics: Consultancy; Horizon Pharma PLC: Other: Consultancy (Spouse).


2021 ◽  
Author(s):  
Anna L Boss ◽  
Tanvi Damani ◽  
Lawrence W Chamley ◽  
Jo L James ◽  
Anna E S Brooks

Single-cell technologies (RNA-sequencing, flow cytometry) are critical tools to reveal how cell heterogeneity impacts developmental pathways. The placenta is a fetal exchange organ, containing a heterogeneous mix of mesenchymal cells (fibroblasts, myofibroblasts, perivascular, and progenitor cells) . Placental mesenchymal stromal cells (pMSC) are also routinely isolated, for therapeutic and research purposes. However, our understanding of the diverse phenotypes of placental mesenchymal lineages, and their relationships remain unclear. We designed a 23-colour flow cytometry panel to assess mesenchymal heterogeneity in first-trimester human placentae. . Four distinct mesenchymal subsets were identified; CD73+CD90+ mesenchymal cells, CD146+CD271+ perivascular cells, podoplanin+CD36+ stromal cells, and CD26+CD90+ myofibroblasts. CD73+CD90+ and podoplanin+CD36+ cells expressed markers consistent with cultured pMSCs, and were explored further. Despite their distinct ex-vivo phenotype, in culture CD73+CD90+ cells and podoplanin+CD36+ cells underwent phenotypic convergence, losing CD271 or CD36 expression respectively, and homogenously exhibiting a basic MSC phenotype (CD73+CD90+CD31-CD144-CD45-). However, some markers (CD26, CD146) were not impacted, or differentially impacted by culture in different populations. Comparisons of cultured phenotypes to pMSCs further suggested cultured pMSCs originate from podoplanin+CD36+ cells as the . This highlights the importance of detailed cell phenotyping to optimise therapeutic capacity, and ensure use of relevant cells in functional assays.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Xi Zhou ◽  
Li Yu ◽  
Min Zhou ◽  
Pengfei Hou ◽  
Long Yi ◽  
...  

Abstract Background This study investigated the mechanisms underlying the preventive effect of dihydromyricetin (DHM) against liver fibrosis involving hepatic stellate cells (HSCs) and hepatic natural killer (NK) cells. Methods A carbon tetrachloride (CCl4)-induced liver fibrosis model was established in C57BL/6 mice to study the antifibrotic effect of DHM based on serum biochemical parameters, histological and immunofluorescence stainings, and the expression of several fibrosis-related markers. Based on the immunoregulatory role of DHM, the effect of DHM on NK cell activation ex vivo was evaluated by flow cytometry. Then, we investigated whether DHM-induced autophagy was involved in HSCs inactivation using enzyme-linked immunosorbent assays, transmission electron microscopy, and western blot analysis. Thereafter, the role of DHM in NK cell-mediated killing was studied by in vitro coculture of NK cells and HSCs, with subsequent analysis by flow cytometry. Finally, the mechanism by which DHM regulates NK cells was studied by western blot analysis. Results DHM ameliorated liver fibrosis in C57BL/6 mice, as characterized by decreased serum alanine transaminase and aspartate transaminase levels, decreased expressions of collagen I alpha 1 (CoL-1α1), collagen I alpha 2 (CoL-1α2), tissue inhibitor of metalloproteinases 1 (TIMP-1), α-smooth muscle actin (α-SMA) and desmin, as well as increased expression of matrix metalloproteinase 1 (MMP1). Interestingly, HSCs activation was significantly inhibited by DHM in vivo and in vitro. As expected, DHM also upregulated autophagy-related indicators in liver from CCl4-treated mice. DHM also prevented TGF-β1-induced activation of HSCs in vitro by initiating autophagic flux. In contrast, the autophagy inhibitor 3-methyladenine markedly abolished the antifibrotic effect of DHM. Surprisingly, the frequency of activated intrahepatic NK cells was significantly elevated by DHM ex vivo. Furthermore, DHM enhanced NK cell-mediated killing of HSCs by increasing IFN-γ expression, which was abolished by an anti-IFN-γ neutralizing antibody. Mechanistically, DHM-induced IFN-γ expression was through AhR-NF-κB/STAT3 pathway in NK cells. Conclusion These results demonstrated that DHM can ameliorate the progression of liver fibrosis and inhibition of HSCs activation by inducing autophagy and enhancing NK cell-mediated killing through the AhR-NF-κB/STAT3-IFN-γ signaling pathway, providing new insights into the preventive role of DHM in liver fibrosis.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A718-A718
Author(s):  
Md Faqrul Hasan ◽  
Alicja Copik

BackgroundNatural killer (NK) cells are innate immune cells that directly kill and coordinate responses against cancer prompting interest in using ex vivo expanded NK cells as an adoptive cell therapy for treatment of cancer. NK cells express a set of activating and inhibitory receptors that regulate their activity. Inhibitory receptor TIGIT (T cell Immunoreceptor with Ig and ITIM domain) is upregulated on intratumoral NK cells in some cancers, inhibits NK cell activity and promotes NK cell exhaustion. In this study, the effect of TIGIT blockade on the anti-tumor activities of ex vivo expanded NK cells was evaluated.MethodsNK cells were activated overnight with cytokines or ex vivo expanded with PM21-particles. Their TIGIT expression was determined with qRT-PCR and flow cytometry. Cytotoxicity was assessed by kinetic, imaging-based assay (Incucyte S3) against A549 and NCI-H1299 cells cultured in 3D. Cytotoxicity was calculated based on untreated controls at different time-points. Results from multiple donors were normalized to cytotoxicity of NK cells with isotype for individual donors and was compared to the cytotoxicity of NK cells with anti-TIGIT. Unpaired t test was used to determine statistical significance. K562 cells stably expressing Polio Virus Receptor (PVR), were used to restimulate A549 spheroid-exposed NK cells to measure IFNγ, TNFα and degranulation. Furthermore, phenotypic changes of NK cells upon TIGIT blockade were examined by analyzing a set of activating and inhibitory receptors by flow cytometry.ResultsThe effect of NK cell expansion/activation on TIGIT expression was assessed. TIGIT was upregulated on expanded and cytokine-activated NK cells both on mRNA and protein level. The effect of TIGIT blockade on NK cell cytotoxicity was examined by co-culturing PM21-NK cells with cancer cells in the presence of anti-TIGIT antibodies or respective isotypes. TIGIT blockade significantly increased cytotoxicity of PM21-NK cells against A549 (1.3 fold, P < 0.0001) and NCI-H1299 (1.3 fold, P = 0.0003) spheroids after 48 h. To access exhaustion, NK cells exposed to A549 spheroids for 7 days were restimulated with PVR+ K562 cells. TIGIT blockade prevented NK cell exhaustion resulting in increased expression of IFNγ, TNFα and surface CD107a on restimulated NK cells. TIGIT blockade did not result in changes to the surface phenotype of NK cells.ConclusionsTIGIT was highly expressed on expanded and cytokine-activated NK cells. TIGIT blockade improved anti-tumor activities of PM21-NK cells. Thus, PM21-NK cells and TIGIT antibodies have translational potential as a combination therapy to improve anti-tumor response.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 993-993
Author(s):  
Youssef Youssef ◽  
Ansel P. Nalin ◽  
Jesse Kowalski ◽  
Megan Broughton ◽  
Matthew Lordo ◽  
...  

Abstract Natural killer (NK) cells are cytotoxic innate lymphoid cells (ILCs) whose development and anti-tumor functions can be critical for the successful treatment and long-term disease-free survival of patients with hematologic malignancies. In humans, NK cells derive from bone marrow resident hematopoietic progenitor cells that traffic to secondary lymphoid tissues (SLTs) where they complete their terminal differentiation and maturation through a series of developmental stages before returning to the blood as mature NK cells. Although major stages of human NK cell development in SLTs have been clearly defined according to the differential surface expression of CD34, CD117, CD94, NKp80, CD16, and CD57 among lineage antigen (Lin) negative lymphocytes, continued investigation has revealed additional phenotypic and functional heterogeneity at each developmental stage. Through extensive ex vivo single-cell RNA sequencing and flow cytometry analyses we have identified two subsets of tonsil-resident Lin -CD34 -CD117 +/-CD94 +NKp80 -CD16 -CD57 - stage 4A NK cells. These two subsets differ in their expression of the inhibitory receptor, CD200R1, which is not expressed by mature NK cells in the peripheral blood from healthy individuals. The majority of stage 4A cells expressed high amounts of surface CD200R1, which correlated with low gene and undetectable protein expression of intracellular cytolytic granules (perforin and granzymes A, B, K, and M), killer immunoglobulin-like receptors (KIRs), and transcription factors required for terminal NK cell maturation (EOMES, T-BET). In addition, upon ex vivo stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin, CD200R1 + stage 4A NKDIs did not produce interferon-gamma (IFN-g), a hallmark feature of mature NK cells. In contrast, many CD200R1 - stage 4A cells constitutively expressed perforin, granzymes, EOMES, and/or T-BET; many expressed KIRs; and many produced IFN-g upon ex vivo stimulation. Furthermore, the frequency of KIR + cells among CD200R1 - stage 4A cells was significantly higher than that among autologous tonsil stage 4B NK cells (Lin -CD34 -CD117 +/-CD94 +NKp80 +CD16 -CD57 -) (20.8 ± 1.65 vs. 8.12 ± 1.66; p &lt; 0.01; n = 14), suggesting that as a population CD200R1 - stage 4A cells are potentially out of sequence in terms of the linear NK cell developmental pathway. Based on these ex vivo findings, we hypothesized that CD200R1 + stage 4A cells represent NK cell precursors, whereas the CD200R1 - stage 4A population contains more mature NK cells that lack NKp80, CD16, and CD57. To further address this hypothesis and to determine their ex vivo potentials for NK cell and non-NK ILC differentiation, we cultured CD200R1 + and CD200R1 - stage 4A cells in vitro in the presence of OP9-DL1 stroma and recombinant human IL-7 and IL-15, conditions previously shown to support all human ILC and NK cell subset differentiation. Under these conditions, both stage 4A populations generated NKp80 + NK cells in bulk and single-cell clonal assays, whereas neither population gave rise to ILC2s (CD294 +) which precede stage 4A NK cells in the developmental scheme. However, while the majority of cultures derived from CD200R1 + stage 4A clones contained ILC3s (CD94 -NKp44 +), significantly fewer clones from CD200R1 - stage 4A cells produced ILC3s (7 of 26 CD200R1 - clones vs. 20 of 23 CD200R1 + clones; p = 0.000587). Moreover, none of the CD200R1 - stage 4A-derived clonal cultures that contained KIR + NK cells contained ILC3s, suggesting that the majority of CD200R1 - stage 4A cells are lineage committed NK cells. Collectively, these data further characterize the heterogeneity of the human tonsil stage 4A NK cell population and identify CD200R1 as a marker distinguishing uncommitted precursor cells from a minor population of cells with otherwise mature NK-associated phenotype and function. In light of the role of CD200R1 in regulating lymphocyte functions in the setting of cancer, further research is warranted to determine its potential role(s) in regulating human NK cell development. Disclosures Blachly: KITE: Consultancy, Honoraria; INNATE: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; AstraZeneca: Consultancy, Honoraria.


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